Difference between revisions of "Timeline of proteins"

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This is a '''timeline of FIXME'''.
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This is a '''timeline of {{w|protein}}s''', a class of macromolecules in the form of {{w|polymer chain}}s made of {{w|amino acid}}s. Proteins are essential nutrients for the human body. This timeline focuses on proteins from a nutritional perspective.
  
 
== Sample questions ==
 
== Sample questions ==
  
The following are some interesting questions that can be answered by reading this timeline:  
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The following are some interesting questions that can be answered by reading this timeline:
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* What are some notable scientific events related to the nutritional aspects of proteins?
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** Sort the full timeline by "Event type" and look for the group of rows with value "Scientific development".
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* What are some notable reviews expressed by experts and competent entities?
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** Sort the full timeline by "Event type" and look for the group of rows with value "Notable comment".
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** You will read reviews by both known experts in the field and organizations, such as the {{w|American Dietetic Association}}.
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* What are some notable recommendations of protein intake issued by competent entities?
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** Sort the full timeline by "Event type" and look for the group of rows with value "Recommendation".
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** You will see recommendations from both experts and important organizations, such as {{w|WHO}} ans {{w|FAO}}.
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* What are some notable publications specialized in proteins?
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** Sort the full timeline by "Event type" and look for the group of rows with value "Literature".
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* Other events are described under the following types: "Focus trend", "Notable report", "Policy", and "Program launch".
  
 
==Big picture==
 
==Big picture==
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{| class="wikitable"
 
{| class="wikitable"
 
! Time period !! Development summary !! More details
 
! Time period !! Development summary !! More details
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| 1920–1950 || Relegated attention || Around this time, nutritional research centers on the discovery of individual {{w|vitamin}}s and {{w|amino acid}}s, putting little interest in human protein requirements, or in the possibility of their not being met.<ref name="Carpenter"/>
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| 1950s–1960s || Mainstream focus || Protein again receives priority attention, with United Nations (UN) agencies being focused on protein malnutrition as the major worldwide nutritional problem.<ref name="fsfgfd"/> The "World Protein Gap" is considered the major cause of infant mortality and retarded development in the Third World but a problem that could be solved by the application of sophisticated technology.<ref name="Carpenter"/> From the 1950s to the mid-1970s, United Nations (UN) agencies were focused on protein malnutrition as the major worldwide nutritional problem.
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| 1970s || Focus decline || United Nations agencies start suspecting about a "protein gap". In the mid-decade, protein malnutrition is suddenly discarded, putting end to years of agencies and international conferences focusing on protein malnutrition.<ref name="fsfgfd">{{cite journal |last1=Semba |first1=Richard D. |title=The Rise and Fall of Protein Malnutrition in Global Health |journal=Annals of Nutrition & Metabolism |date=2016 |volume=69 |issue=2 |pages=79–88 |doi=10.1159/000449175 |url=https://pubmed.ncbi.nlm.nih.gov/27576545/ |issn=1421-9697}}</ref>
 
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{| class="sortable wikitable"
 
{| class="sortable wikitable"
! Year !! Month and date !! Event type !! Details
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! Year !! Event type !! Details
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| 1806 || Scientific development || French chemists {{w|Louis Nicolas Vauquelin}} and {{w|Pierre Jean Robiquet}} first isolate {{w|asparagine}} in a crystalline form from {{w|asparagus}} juice.<ref>{{cite journal |title=La découverte d'un nouveau principe végétal dans le suc des asperges |vauthors=Vauquelin LN, Robiquet PJ |journal=Annales de Chimie |year=1806 |volume=57 |pages=88–93 |language=fr|hdl=2027/nyp.33433062722578 }}</ref><ref>{{cite book | vauthors = Plimmer RH | veditors = Plimmer RH, Hopkins FG  |title= The chemical composition of the proteins |url= https://books.google.com/books?id=7JM8AAAAIAAJ&pg=PA112 |access-date= January 18, 2010 |edition= 2nd |series= Monographs on biochemistry |volume= Part I. Analysis |orig-year= 1908 |year= 1912 |publisher= Longmans, Green and Co. |location= London|page= 112}}</ref> A non-essential amino acid in humans<ref>{{cite web |title=Asparagine |url=https://pubchem.ncbi.nlm.nih.gov/compound/Asparagine#:~:text=Asparagine%20is%20a%20non%2Dessential,be%20eliminated%20from%20the%20body. |website=pubchem.ncbi.nlm.nih.gov |access-date=7 October 2021 |language=en}}</ref>, it is closely related to {{w|aspartic acid}}.<ref>{{cite web |title=asparagine {{!}} chemical compound |url=https://www.britannica.com/science/asparagine |website=Encyclopedia Britannica |access-date=7 October 2021 |language=en}}</ref> Research shows that L-asparagine is able to protect cancer cells from dying due to a loss of {{w|glutamine}}.<ref>{{cite web |title=Asparagus and Breast Cancer: Does Asparagus Help Fight or Spread It? |url=https://www.healthline.com/health/breast-cancer/asparagus-breast-cancer#how-it-works |website=Healthline |access-date=7 October 2021 |language=en |date=19 March 2019}}</ref> Rich food sources include dairy, whey, beef, poultry, eggs, fish, seafood, asparagus, potatoes, legumes, nuts, seeds, soy, and whole grains. Poor food sources include most fruits and vegetables.<ref>{{cite web |title=Low-Asparagine Diet Could Slow Breast Cancer’s Spread |url=https://www.genengnews.com/topics/omics/low-asparagine-diet-could-slow-breast-cancers-spread/ |website=genengnews.com |access-date=7 October 2021}}</ref>
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| 1810 || Scientific development || English chemist {{w|William Hyde Wollaston}} indirectly discovers {{w|cystine}}, when managing to isolate a crystalline substance from urinary calculi (kidney stones) and calls it “cystic oxide”.<ref>{{cite web |title=Cysteine: an Essential Inessential Amino Acid |url=https://www.eurpepsoc.com/wp-content/uploads/2017/01/Preston_Jan_2017.pdf#:~:text=Cysteine%20was%20discovered%20indirectly%20in,amino%20acid%20to%20be%20discovered. |website=eurpepsoc.com}}</ref> Cystine is the oxidized dimer form of the {{w|amino acid}} {{w|cysteine}} It is a non-essential amino acid important for making protein, and for other metabolic functions.<ref>{{cite web |title=Cysteine - Health Encyclopedia - University of Rochester Medical Center |url=https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=19&contentid=Cysteine |website=www.urmc.rochester.edu |access-date=2 October 2021}}</ref>
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| 1816 || Scientific development || French physiologist {{w|François Magendie}} demonstrates that dogs would die if fed nothing but {{w|carbohydrate}}s or fat, i.e., the principal nonnitrogenous food components.<ref name="Carpenter"/> 
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| 1819 || Scientific development || The discovery of {{w|leucine}} is attributed to French chemist {{w|Joseph Proust}} who reports its separation from fermented milk curds.<ref>{{cite web |title=Leucine |url=https://www.drugfuture.com/chemdata/Leucine.html#:~:text=Discovery%20of%20leucine%20is%20attributed,Greenberg%2C%20Ed. |website=www.drugfuture.com}}</ref> Leucine is one of the three branched-chain amino acids (BCAA), along with {{w|isoleucine}} and {{w|valine}}.<ref>{{cite journal |last1=Mero |first1=Antti |title=Leucine Supplementation and Intensive Training: |journal=Sports Medicine |date=1999 |volume=27 |issue=6 |pages=347–358 |doi=10.2165/00007256-199927060-00001}}</ref> Like valine, leucine is critical for protein synthesis and muscle repair.<ref>{{cite web |title=10 Healthy High Leucine Foods |url=https://www.healthline.com/nutrition/10-high-leucine-foods |website=Healthline |access-date=4 October 2021 |language=en |date=9 June 2021}}</ref> Rich food sources include {{w|chicken}}, {{w|beef}}, {{w|pork}}, {{w|fish}} ({{w|tuna}}), {{w|tofu}}, canned beans, {{w|milk}}, {{w|cheese}}, squash seeds, and {{w|egg}}s.<ref>{{cite web |title=Top 10 Foods Highest in Leucine |url=https://www.myfooddata.com/articles/high-leucine-foods.php |website=myfooddata |access-date=7 October 2021 |language=english}}</ref>
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| 1820 || Scientific development || {{w|Glycine}} is discovered by French chemist {{w|Henri Braconnot}} when he hydrolyzes {{w|gelatin}} by boiling it with {{w|sulfuric acid}}.<ref>{{Cite book |last=Plimmer |first=R.H.A. |url=https://books.google.com/books?id=7JM8AAAAIAAJ&pg=PA112 |title=The chemical composition of the proteins |publisher=Longmans, Green and Co. |year=1912 |editor-last=Plimmer |editor-first=R.H.A. |edition=2nd |series=Monographs on biochemistry |volume=Part I. Analysis |location=London |page=82 |access-date=January 18, 2010 |orig-year=1908 |editor-last2=Hopkins |editor-first2=F.G. }}</ref> Glycine is the main amino acid in {{w|collagen}}, the most abundant protein in the body.<ref>{{cite journal |last1=Razak |first1=Meerza Abdul |last2=Begum |first2=Pathan Shajahan |last3=Viswanath |first3=Buddolla |last4=Rajagopal |first4=Senthilkumar |title=Multifarious Beneficial Effect of Nonessential Amino Acid, Glycine: A Review |journal=Oxidative Medicine and Cellular Longevity |date=2017 |volume=2017 |pages=1–8 |doi=10.1155/2017/1716701}}</ref> It is structural of connective tissue, such as bone, skin, ligaments, tendons and cartilage.<ref>{{cite web |title=Top 9 Benefits and Uses of Glycine |url=https://www.healthline.com/nutrition/glycine |website=Healthline |access-date=4 October 2021 |language=en |date=12 December 2018}}</ref><ref>{{cite web |title=Collagen — What Is It and What Is It Good For? |url=https://www.healthline.com/nutrition/collagen |website=Healthline |access-date=4 October 2021 |language=en |date=5 May 2020}}</ref> Glycine is found in high-protein foods including {{w|meat}}, {{w|fish}}, {{w|egg}}s, {{w|dairy}} and {{w|legume}}s.<ref>{{cite web |last1=Breus |first1=Dr Michael |title=The Connection Between Glycine and Sleep |url=https://thesleepdoctor.com/2018/07/23/understanding-glycine/ |website=The Sleep Doctor |access-date=7 October 2021 |date=23 July 2018}}</ref>
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| 1827 || Scientific development || {{w|Aspartic acid}} (or aspartate) is first discovered by {{w|Auguste-Arthur Plisson}} and {{w|Étienne Ossian Henry}}.<ref>{{cite book |last1=Berzelius (friherre) |first1=Jöns Jakob |title=Traité de chimie |date=1839 |publisher=A. Wahlen et Cie. |url=https://books.google.com/books?id=szLPAAAAMAAJ |language=fr}}</ref> It is a non-essential amino acid, meaning that it is readily and naturally synthesized by mammals.<ref>{{cite web |title=Aspartic Acid - an overview {{!}} ScienceDirect Topics |url=https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/aspartic-acid|title=Amyloid |website=www.sciencedirect.com |access-date=7 October 2021}}</ref> D-aspartic acid (D-AA) regulates testosterone synthesis and may act on a stimulatory receptor (NMDA).<ref>{{cite web |last1=Frank |first1=Kurtis |last2=Patel |first2=Kamal |last3=Lopez |first3=Gregory |last4=Willis |first4=Bill |title=D-Aspartic Acid Research Analysis |url=https://examine.com/supplements/d-aspartic-acid/ |access-date=7 October 2021 |language=en |date=17 September 2019}}</ref>
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| 1827 || Scientific development || {{w|Taurine}} is first isolated from ox bile by German scientists {{w|Friedrich Tiedemann}} and {{w|Leopold Gmelin}}.<ref>{{cite journal |title=Einige neue Bestandtheile der Galle des Ochsen| vauthors = Tiedemann F, Gmelin L |journal=Annalen der Physik|volume=85|issue=2|pages=326–37|year=1827|url=https://zenodo.org/record/1423514|doi=10.1002/andp.18270850214}}</ref> It is a type of chemical called an amino sulfonic acid. It occurs naturally in the human body.<ref>{{cite web |title=TAURINE: Overview, Uses, Side Effects, Precautions, Interactions, Dosing and Reviews |url=https://www.webmd.com/vitamins/ai/ingredientmono-1024/taurine |website=www.webmd.com |access-date=9 October 2021 |language=en}}</ref> Taurine is found naturally in {{w|meat}}, {{w|fish}}, {{w|dairy}} products and {{w|human milk}}, and it's also available as a dietary supplement.<ref>{{cite web |title=Does your energy drink contain taurine? |url=https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/taurine/faq-20058177 |website=Mayo Clinic |access-date=8 October 2021 |language=en}}</ref>
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| 1833 || Scientific development || The {{w|empirical formula}} for {{w|asparagine}} is first determined by French chemists Antoine François Boutron Charlard and {{w|Théophile-Jules Pelouze}}. In the same year, German chemist [[w:Justus von Liebig|Justus Liebig]] provides a more accurate formula.<ref>{{cite journal |last1=Boutron-Charlard |last2=Pelouze |title=Ueber das Asparamid (Asparagin des Herrn Robiquet) und die Asparamidsäure |journal=Annalen der Chemie |date=1833 |volume=6 |pages=75–88 |url=https://babel.hathitrust.org/cgi/pt?id=uva.x002457885;view=1up;seq=467 |trans-title=On asparamide (the asparagine of Mr. Robiquet) and aspartic acid |language=de |doi=10.1002/jlac.18330060111}}  The empirical formula of asparagine appears on p. 80.</ref><ref>{{cite journal |last1=Liebig |first1=Justus |title=Ueber die Zusammensetzung des Asparamids und der Asparaginsäure |journal=Annalen der Physik und Chemie |date=1834 |volume=107 |issue=14 |pages=220–224 |doi=10.1002/andp.18341071405}}</ref>
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| 1846 || Scientific development || English industrial chemist {{w|Edmund Ronalds}} discovers {{w|taurine}} in human {{w|bile}}.<ref>{{cite journal | vauthors = Ronalds BF |date=2019|title=Bringing Together Academic and Industrial Chemistry: Edmund Ronalds' Contribution|journal=Substantia|volume=3|issue=1|pages=139–152}}</ref> 
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| 1846 || Scientific development || {{w|Tyrosine}} is first discovered by German chemist {{w|Justus von Liebig}} in the protein {{w|casein}} from cheese.<ref name="urltyrosine — Infoplease.com">{{cite encyclopedia | url = http://www.infoplease.com/ce6/sci/A0849873.html | title = Tyrosine  | year = 2007 | encyclopedia = The Columbia Electronic Encyclopedia, 6th ed | publisher = Infoplease.com — Columbia University Press  | access-date = 1 October 2021}}</ref><ref name="urlOnline Etymology Dictionary">{{cite web | url = http://www.etymonline.com/index.php?term=tyrosine | title = Tyrosine | vauthors = Harper D | year = 2001 | work = Online Etymology Dictionary | access-date = 2008-04-20}}</ref> It is one of the 20 standard [[w:proteinogenic amino acid|amino acid]]s that are used by [[w:cell (biology)|cells]] to [[w:protein biosynthesis|synthesize proteins]].<ref name="eeeee">{{cite web |title=Tyrosine: Benefits, Side Effects and Dosage |url=https://www.healthline.com/nutrition/tyrosine#:~:text=Tyrosine%20is%20a%20popular%20dietary,effects%20and%20interact%20with%20medications. |website=Healthline |access-date=4 October 2021 |language=en |date=1 February 2018}}</ref> Tyrosine is an essential amino acid.<ref>{{cite web |title=Amino Acids - Tyrosine |url=http://www.biology.arizona.edu/biochemistry/problem_sets/aa/tyrosine.html#:~:text=Tyrosine%20Y%20(Tyr)&text=Tyrosine%2C%20an%20essential%20amino%20acid,more%20soluble%20that%20is%20phenylalanine. |website=www.biology.arizona.edu |access-date=8 October 2021}}</ref> It is used to improve alertness, attention and focus.<ref name="eeeee"/> Sources include {{w|soy}} products, {{w|chicken}}, {{w|turkey}}, {{w|fish}}, {{w|peanut}}s, {{w|almond}}s, {{w|avocado}}s, {{w|banana}}s, {{w|milk}}, {{w|cheese}}, {{w|yogurt}}, cottage cheese, lima beans, {{w|pumpkin}} seeds, and {{w|sesame}} seeds.<ref>{{cite web |title=Tyrosine Information {{!}} Mount Sinai - New York |url=https://www.mountsinai.org/health-library/supplement/tyrosine#:~:text=Dietary%20Sources,pumpkin%20seeds%2C%20and%20sesame%20seeds. |website=Mount Sinai Health System |access-date=8 October 2021}}</ref>
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| 1858 || Scientific development || French chemist [[w:Auguste André Thomas Cahours|Auguste Cahours]] determines that {{w|glycine}} is an {{w|amine}} of {{w|acetic acid}}.<ref>{{Cite journal |last=Cahours |first=A. |date=1858 |title=Recherches sur les acides amidés |trans-title=Investigations into aminated acids |url=https://babel.hathitrust.org/cgi/pt?id=umn.31951d00008355e;view=1up;seq=1050 |journal=Comptes Rendus |language=fr |volume=46 |pages=1044–1047}}</ref> 
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| 1859 || Scientific development || German scientists {{w|Nikolaus Friedreich}} and {{w|Friedrich August Kekulé von Stradonitz}} demonstrate that, rather than consisting of cellulose, "{{w|amyloid}}" actually is rich in protein.<ref name="Sipe">{{cite journal | vauthors = Sipe JD, Cohen AS | title = Review: history of the amyloid fibril | journal = Journal of Structural Biology | volume = 130 | issue = 2–3 | pages = 88–98 | date = June 2000 | pmid = 10940217 | doi = 10.1006/jsbi.2000.4221 }}</ref>
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| 1865 || Scientific development || {{w|Serine}} is first obtained by Emil Cramer from {{w|silk}} protein, a particularly rich source. Its name is derived from the {{w|Latin}} for silk, ''sericum''.<ref>{{cite web |title='Journal für praktische Chemie : practical applications and applied chemistry ; covering all aspects of applied chemistry. 96. 1865' - Digitalisat {{!}} MDZ |url=http://reader.digitale-sammlungen.de/de/fs1/object/display/bsb10072519_00012.html |website=www.digitale-sammlungen.de |access-date=7 October 2021}}</ref> Serine comes in two forms: L-serine and D-serine.<ref>{{cite web |title=SERINE: Overview, Uses, Side Effects, Precautions, Interactions, Dosing and Reviews |url=https://www.webmd.com/vitamins/ai/ingredientmono-1615/serine |website=www.webmd.com |access-date=7 October 2021 |language=en}}</ref> D-serine is used for schizophrenia, cognitive function, and other conditions.<ref>{{cite web |title=SERINE: Overview, Uses, Side Effects, Precautions, Interactions, Dosing and Reviews |url=https://www.webmd.com/vitamins/ai/ingredientmono-1615/serine#:~:text=D%2Dserine%20is%20used%20for,)%2C%20and%20many%20other%20conditions. |website=www.webmd.com |access-date=8 October 2021 |language=en}}</ref> It is found in {{w|soybean}}s, {{w|nut}}s (especially {{w|peanut}}s, {{w|almond}}s, and {{w|walnut}}s), {{w|egg}}s, {{w|chickpea}}s, {{w|lentil}}s, {{w|meat}}, and {{w|fish}} (especially {{w|shellfish}}).<ref>{{cite web |title=Serine - an overview {{!}} ScienceDirect Topics |url=https://www.sciencedirect.com/topics/neuroscience/serine |website=www.sciencedirect.com |access-date=7 October 2021}}</ref> 
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| 1866 || Scientific development || {{w|Glutamic acid}} is discovered and identified by German chemist {{w|Karl Heinrich Ritthausen}}.<ref>{{cite book |author= R. H. A. Plimmer |editor1=R. H. A. Plimmer |editor2=F. G. Hopkins |title= The Chemical Constitution of the Protein |url= https://books.google.com/books?id=7JM8AAAAIAAJ&pg=PA114 |access-date= June 3, 2012 |edition= 2nd |series= Monographs on biochemistry |volume= Part I. Analysis |orig-year= 1908 |year= 1912 |publisher= Longmans, Green and Co. |location= London |page= 114}}</ref> It is a non-essential amino acid that occurs in plants and animals and is formed via protein metabolism.<ref>{{cite web |title=Glutamic acid |url=https://pubchem.ncbi.nlm.nih.gov/compound/Glutamic-acid |website=pubchem.ncbi.nlm.nih.gov |language=en}}</ref> 
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| 1869 || Scientific development || German scientists {{w|Johannes Wislicenus}} and {{w|Adolf Eugen Fick}} conduct an experiment in which they measure their urinary nitrogen during and after climbing a Swiss mountain, seeming to demonstrate conclusively that there is no apparent extra breakdown of protein that would be required to provide the energy used in the climb.<ref name="Carpenter"/> 
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| 1879 || Scientific development || German chemist [[w:Ernst Schulze (chemist)|Ernst Schulze]] and Johann Barbieri first identify {{w|phenylalanine}} as a constituent of plant proteins.<ref>{{cite book |title=Proteins, Enzymes, Genes: The Interplay of Chemistry and Biology |publisher=Yale University Press |isbn=978-0-300-15359-0 |url=https://books.google.com.ar/books?id=X6skaZlZNdsC&pg=PA179&lpg=PA179&dq=Ernst+Schulze+barbieri&source=bl&ots=OgPv3UOViv&sig=ACfU3U3maLbOgNn1AJfOdwokLynIZnSzog&hl=en&sa=X&ved=2ahUKEwidwc_KsrHzAhWrqZUCHfryCU8Q6AF6BAgUEAM#v=onepage&q=Ernst%20Schulze%20barbieri&f=false |language=en}}</ref><ref>{{cite journal |title=Phenylalanine hydroxylase and phenylketonuria |date=2016 |doi=10.13140/RG.2.1.3339.3529}}</ref><ref>{{cite book |title=Advances in Protein Chemistry |date=1 January 1955 |publisher=Academic Press |isbn=978-0-08-058183-5 |url=https://books.google.com.ar/books?id=91DSIOLUrRIC&pg=PA34&dq=phenylalanine+1879&hl=en&sa=X&ved=2ahUKEwjD-YHVsbHzAhVBFrkGHSgXABsQ6AF6BAgDEAI#v=onepage&q=phenylalanine%201879&f=false |language=en}}</ref> Phenylalanine is one of the nine {{w|essential amino acid}}s. It occurs naturally in many protein-rich foods, such as milk, eggs and meat.<ref>{{cite web |title=Phenylalanine in diet soda: Is it harmful? |url=https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/expert-answers/phenylalanine/faq-20058361 |website=Mayo Clinic |access-date=4 October 2021 |language=en}}</ref>   
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| 1882 || Scientific development || German chemists {{w|Emil Erlenmeyer}} and Andreas Lipp first synthesize {{w|phenylalanine}} from {{w|phenylacetaldehyde}}, {{w|hydrogen cyanide}}, and {{w|ammonia}}.<ref>{{cite book |last1=Thorpe |first1=Sir Edward |title=A Dictionary of Applied Chemistry (Volume III) |date=10 December 2019 |publisher=Alpha Editions |isbn=978-93-5395-007-1 |url=https://books.google.com.ar/books/about/A_Dictionary_of_Applied_Chemistry_Volume.html?id=d7O3zAEACAAJ&source=kp_book_description&redir_esc=y |language=en}}</ref> 
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| 1883 || Scientific development || German chemists Ernst Schulze and E. Bosshard isolate L-glutamine from the juice of sugarbeets. L-glutamine is the most common amino acid in human blood and a key component of proteins.<ref name="sdsa">{{cite web |title=L-Glutamine |url=https://www.acs.org/content/acs/en/molecule-of-the-week/archive/g/l-glutamine.html#:~:text=In%201883%2C%20German%20chemists%20Ernst,a%20key%20component%20of%20proteins. |website=American Chemical Society |access-date=2 October 2021 |language=en}}</ref> The most abundant free amino acid in the body, glutamine is produced in the muscles and is distributed by the blood to the organs that need it.<ref>{{cite web |title=GLUTAMINE: Overview, Uses, Side Effects, Precautions, Interactions, Dosing and Reviews |url=https://www.webmd.com/vitamins/ai/ingredientmono-878/glutamine |website=www.webmd.com |access-date=4 October 2021 |language=en}}</ref> 
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| 1886 || Scientific development || Ernst Schulze becomes the first to isolate L-arginine from lupin seedlings. L-arginine is an important amino acid in protein biosynthesis.<ref name="sdsa"/> 
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| 1889 || Scientific development || {{w|Lysine}} is first isolated by German biological chemist Ferdinand Heinrich Edmund Drechsel from the protein {{w|casein}} in milk.<ref>{{cite journal | vauthors = Drechsel E | title=Zur Kenntniss der Spaltungsprodukte des Caseïns|journal=Journal für Praktische Chemie|date=1889|volume=39|pages=425–429|url=https://babel.hathitrust.org/cgi/pt?id=osu.32435060196680;view=1up;seq=441|series=2nd series|trans-title=[Contribution] to [our] knowledge of the cleavage products of casein|language=de| doi=10.1002/prac.18890390135}}  On p. 428, Drechsel presented an empirical formula for the chloroplatinate salt of lysine – C<sub>8</sub>H<sub>16</sub>N<sub>2</sub>O<sub>2</sub>Cl<sub>2</sub>•PtCl<sub>4</sub> + H<sub>2</sub>O – but he later admitted that this formula was wrong because the salt's crystals contained ethanol instead of water. See:  {{cite journal | vauthors = Drechsel E | year = 1891 | title = Der Abbau der Eiweissstoffe | trans-title = The disassembly of proteins | language = de | journal = Archiv für Anatomie und Physiologie | pages = 248–278 }};  {{cite journal | vauthors = Drechsel E | title = Zur Kenntniss der Spaltungsproducte des Caseïns | trans-title = Contribution] to [our] knowledge of the cleavage products of casein | language = de | pages = 254–260 | url =  https://babel.hathitrust.org/cgi/pt?id=coo.31924056294253;view=1up;seq=268 | quote = From p. 256:]  ''" … die darin enthaltene Base hat die Formel C<sub>6</sub>H<sub>14</sub>N<sub>2</sub>O<sub>2</sub>.  Der anfängliche Irrthum ist dadurch veranlasst worden, dass das Chloroplatinat nicht, wie angenommen ward, Krystallwasser, sondern Krystallalkohol enthält, … "''  ( … the base [that's] contained therein has the [empirical] formula C<sub>6</sub>H<sub>14</sub>N<sub>2</sub>O<sub>2</sub>. The initial error was caused by the chloroplatinate containing not water in the crystal (as was assumed), but ethanol … ) }}</ref> An essential amino acid, lysine is important for normal growth and muscle turnover and used to form carnitine, a substance found in most cells of the body.<ref>{{cite web |title=4 Impressive Health Benefits of Lysine |url=https://www.healthline.com/nutrition/lysine-benefits |website=Healthline |access-date=8 October 2021 |language=en |date=6 October 2018}}</ref> 
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| 1896 || Scientific development || {{w|Histidine}} is first isolated by German physician {{w|Albrecht Kossel}} and {{w|Sven Gustaf Hedin}}.<ref>{{Cite journal|last1=Vickery|first1=Hubert Bradford|last2=Leavenworth|first2=Charles S.|title=On the Separation of Histidine and Arginine|date=1928-08-01|url=http://www.jbc.org/content/78/3/627.full.pdf|journal=Journal of Biological Chemistry|language=en|volume=78|issue=3|pages=627–635|doi=10.1016/S0021-9258(18)83967-9|issn=0021-9258|doi-access=free}}</ref> A semi-essential amino acid (children should obtain it from food)<ref>{{cite web |title=Health Topics A-Z |url=https://www.peacehealth.org/medical-topics/id/hn-2861001 |website=PeaceHealth |access-date=10 October 2021 |language=en}}</ref>, histidine is needed in humans for growth and tissue repair.<ref name="Histidine">{{cite web |title=Histidine |url=https://pubchem.ncbi.nlm.nih.gov/compound/l-histidine#:~:text=Histidine%20is%20a%20semi%2Dessential,metabolized%20to%20the%20neurotransmitter%20histamine. |website=pubchem.ncbi.nlm.nih.gov |access-date=8 October 2021 |language=en}}</ref> It is important for maintenance of myelin sheaths that protect nerve cells and is metabolized to the neurotransmitter histamine.<ref name="Histidine"/> Histidine is abundant in meat, fish, poultry, nuts, seeds, and whole grains.<ref>{{cite web |title=Essential amino acids: Definition, benefits, and foods |url=https://www.medicalnewstoday.com/articles/324229#incorporating-essential-amino-acids-into-the-diet |website=www.medicalnewstoday.com |access-date=10 October 2021 |language=en |date=21 January 2019}}</ref>
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| 1898 || Scientific development || The first use of the term "amino acid" in the English language dates from this year.<ref>{{cite web |title=amino- {{!}} Etymology, origin and meaning of prefix amino- by Etymonline |url=https://www.etymonline.com/word/amino- |website=www.etymonline.com |access-date=1 November 2021 |language=en}}</ref>
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| 1899 || Scientific development || {{w|Cystine}} is isolated from the [[w:Horn (anatomy)|horn]] of a {{w|cow}}.<ref>[http://www.britannica.com/eb/article-9028437 "cystine"]. ''Encyclopædia Britannica''. 2007. Encyclopædia Britannica Online. 27 July 2007</ref> 
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| 1890s || Scientific development || The {{w|United States Department of Agriculture}} recommends over 110 g dietary protein per day for working men.<ref name="Carpenter">{{cite journal |last1=Carpenter |first1=KJ |title=The history of enthusiasm for protein. |journal=The Journal of nutrition |date=July 1986 |volume=116 |issue=7 |pages=1364-70 |doi=10.1093/jn/116.7.1364 |pmid=3528432}}</ref>   
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| 1900 || Recommendation || The official {{w|United States Department of Agriculture}} recommendations around this time are concerned only with providing sufficient protein and energy and how these could be purchased economically.<ref name="Carpenter"/> 
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| 1900 || Scientific development || German chemist {{w|Richard Willstätter}} first isolates {{w|proline}}<ref>{{Citation |author= R.H.A. Plimmer |editor= R.H.A. Plimmer & F.G. Hopkins |title= The chemical composition of the proteins |url= https://books.google.com/books?id=7JM8AAAAIAAJ&pg=PA130 |access-date= September 20, 2010 |edition= 2nd |series= Monographs on biochemistry |volume= Part I. Analysis |orig-year= 1908 |year= 1912 |publisher= Longmans, Green and Co. |location= London|page= 130}}</ref> and publishes the synthesis of proline from phthalimide propylmalonic ester.<ref>{{cite web |title=Proline - Cas 147-85-3 - nonessential amino acid |url=https://web.archive.org/web/20151127055301/http://www.aminoacidsguide.com/Pro.html |website=web.archive.org |access-date=4 October 2021 |date=27 November 2015}}</ref> A nonessential amino acid<ref>{{cite web |title=Proline - an overview {{!}} ScienceDirect Topics |url=https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/proline |website=www.sciencedirect.com |access-date=4 October 2021}}</ref>, proline is helpful for repairing damage to the skin.<ref>{{cite web |title=The Amino Acid that Heals Wounds & Supports Digestion |url=https://draxe.com/nutrition/proline/ |website=Dr. Axe}}</ref> 
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| 1901 || Scientific development || German chemist {{w|Hermann Emil Fischer}} first isolates {{w|Valine}} from {{w|casein}}.<ref>{{cite encyclopedia |url=http://www.britannica.com/EBchecked/topic/622178/valine |title=Valine |encyclopedia=Encyclopædia Britannica Online |access-date=1 October 2021}}</ref> A branched-chain essential amino acid with stimulant activity, valine promotes muscle growth and tissue repair. It is a precursor in the penicillin biosynthetic pathway.<ref>{{cite web |title=Valine |url=https://go.drugbank.com/drugs/DB00161 |website=go.drugbank.com |access-date=4 October 2021}}</ref>  Valine is found mainly in protein food sources such as meats, fish, soy, and dairy.<ref>{{cite web |title=Valine - Health Encyclopedia - University of Rochester Medical Center |url=https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=19&contentid=Valine |website=www.urmc.rochester.edu |access-date=4 October 2021}}</ref>   
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| 1901 || Scientific development || British biochemists {{w|Frederick Gowland Hopkins}} and Sydney William Cole discover {{w|tryptophan}} in the milk derivative {{w|casein}}.<ref>{{cite web |title=L-Tryptophan |url=https://www.acs.org/content/acs/en/molecule-of-the-week/archive/t/tryptophan.html#:~:text=In%201901%2C%20British%20biochemists%20Frederick,for%20the%20discovery%20of%20vitamins.) |website=American Chemical Society |access-date=4 October 2021 |language=en}}</ref> An essencial amino acid, tryptophan is vital for a wide variety of metabolic functions that affect the mood, cognition, and behavior.<ref>{{cite web |title=Top Foods High in Tryptophan |url=https://www.webmd.com/diet/foods-high-in-tryptophan#1 |website=WebMD |access-date=4 October 2021 |language=en}}</ref> 
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| 1902 || Scientific development || The structure of {{w|serine}} is established.<ref>{{cite web |title=Serine {{!}} Encyclopedia.com |url=http://www.encyclopedia.com/topic/serine.aspx |website=www.encyclopedia.com |access-date=7 October 2021}}</ref> 
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| 1902 || Scientific development || German chemists [[w:Hermann Emil Fischer|Emil Fischer]] and Fritz Weigert determine lysine's chemical structure by synthesizing it.<ref>{{cite journal |last1=Fischer |first1=Emil |last2=Weigert |first2=Fritz |title=Synthese der α, ϵ-Diaminocapronsäure (Inactives Lysin) |journal=Berichte der deutschen chemischen Gesellschaft |date=July 1902 |volume=35 |issue=3 |pages=3772–3778 |doi=10.1002/cber.190203503211}}</ref> 
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| 1902 || Scientific development || [[w:Hermann Emil Fischer|Emil Fischer]] isolates {{w|hydroxyproline}} from hydrolyzed {{w|gelatin}}.<ref>{{cite book |author= R.H.A. Plimmer |editor1=R.H.A. Plimmer |editor2=F.G. Hopkins |title= The chemical composition of the proteins |url= https://books.google.com/books?id=7JM8AAAAIAAJ&pg=PA132 |access-date= January 18, 2010 |edition= 2nd |series= Monographs on biochemistry |volume= Part I. Analysis |orig-year= 1908 |year= 1912 |publisher= Longmans, Green and Co. |location= London|page= 132}}</ref> 
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| 1902 || Recommendation || W. O. Atwater recommends a dietary intake of 125 g protein per day for the average American adult, because he thinks that U.S. workmen generally work harder than Germans.<cite>W. O. Atwater, ''Principles of Nutrition and Nutritive Value of Food'', USDA Farmers’ Bull, no. 142, 1902</cite> 
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| 1903 || Scientific development || German chemist {{w|Felix Ehrlich}} discovers {{w|isoleucine}} in {{w|hemoglobin}}.<ref>{{cite web |title=Isoleucine Explained |url=http://everything.explained.today/Isoleucine/ |website=everything.explained.today |access-date=4 October 2021}}</ref> Isoleucine is an amino acid present in most common proteins.<ref>{{cite web |title=isoleucine {{!}} chemical compound |url=https://www.britannica.com/science/isoleucine |website=Encyclopedia Britannica |access-date=4 October 2021 |language=en}}</ref> It is an essential amino acid<ref>{{cite web |title=Amino Acids - Alanine |url=http://www.biology.arizona.edu/biochemistry/problem_sets/aa/isoleusine.html |website=www.biology.arizona.edu |access-date=4 October 2021}}</ref>, critical in physiological functions of the whole body, such as growth, immunity, protein metabolism, fatty acid metabolism and glucose transportation. It can improve the immune system, including immune organs, cells and reactive substances.<ref>{{cite journal |last1=Gu |first1=Changsong |last2=Mao |first2=Xiangbing |last3=Chen |first3=Daiwen |last4=Yu |first4=Bing |last5=Yang |first5=Qing |title=Isoleucine Plays an Important Role for Maintaining Immune Function |journal=Current Protein & Peptide Science |date=27 June 2019 |volume=20 |issue=7 |pages=644–651 |doi=10.2174/1389203720666190305163135}}</ref> Isoleucine is abundant in meat, fish, poultry, eggs, cheese, lentils, nuts, and seeds.<ref>{{cite web |title=Essential amino acids: Definition, benefits, and foods |url=https://www.medicalnewstoday.com/articles/324229 |website=www.medicalnewstoday.com |access-date=10 October 2021 |language=en |date=21 January 2019}}</ref>
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| 1905 || Scientific development || Synthetic {{w|isoleucine}} is originally reported by French chemist {{w|Louis Bouveault}}.<ref>{{cite web |last1=texte |first1=Académie des sciences (France) Auteur du |title=Comptes rendus hebdomadaires des séances de l'Académie des sciences / publiés... par MM. les secrétaires perpétuels |url=https://gallica.bnf.fr/ark:/12148/bpt6k30949/f1689.table |website=Gallica |language=EN |date=January 1905}}</ref><ref>{{cite web |title=[:it]Isoleucina: formula, storia, biosintesi, presenza in natura, funzioni[:] |url=https://antropocene.it/en/2020/11/30/isoleucina/ |website=Un Mondo Ecosostenibile |access-date=1 October 2021 |date=30 November 2020}}</ref>
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| 1909 || Literature || American biochemist [[w:Thomas Burr Osborne (chemist)|Thomas Burr Osborne]] publishes ''The Vegetable Proteins''.<ref>{{cite web |title=Thomas Burr Osborne |url=https://prabook.com/web/thomas_burr.osborne/3735974 |website=prabook.com |access-date=22 October 2021 |language=en-EN}}</ref>
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| 1912 || Scientific development || {{w|Felix Ehrlich}} demonstrates that {{w|yeast}} metabolizes the natural amino acids essentially by splitting off {{w|carbon dioxide}} and replacing the [[w:Amine|amino group]] with a [[w:hydroxyl|hydroxyl group]]. By this [[w:chemical reaction|reaction]], tryptophan gives rise to {{w|tryptophol}}.<ref>{{cite journal | url = http://www.jbc.org/content/88/3/659.full.pdf | title = A synthesis of tryptophol | vauthors = Jackson RW | journal = Journal of Biological Chemistry | volume = 88 | issue = 3 | pages = 659–662 | year = 1930 | doi = 10.1016/S0021-9258(18)76755-0 | doi-access = free }}</ref>
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| 1914 || Scientific development || {{w|Citrulline}} is first isolated from {{w|watermelon}} by [[w:Japan|Japanese]] researchers Yotaro Koga and Ryo Odake.<ref>{{Cite journal|last=Fragkos|first=Konstantinos C.|last2=Forbes|first2=Alastair|date=September 2011|title=Was citrulline first a laxative substance? The truth about modern citrulline and its isolation|journal=Nihon Ishigaku Zasshi. [Journal of Japanese History of Medicine]|volume=57|issue=3|pages=275–292|issn=0549-3323|pmid=22397107|url=http://discovery.ucl.ac.uk/1317394/1/1317394.pdf}}</ref> It is a naturally occurring amino acid.<ref>{{cite web |title=L-CITRULLINE: Overview, Uses, Side Effects, Precautions, Interactions, Dosing and Reviews |url=https://www.webmd.com/vitamins/ai/ingredientmono-1245/l-citrulline |website=www.webmd.com |access-date=7 October 2021 |language=en}}</ref> Two commonly seen forms of citrulline seen are citrulline malate and l-citrulline.<ref>{{cite web |title=Citrulline Malate: The Most Mis-Used Weapon in Aerobic and Anaerobic Performance |url=https://www.just-fly-sports.com/citrulline-malate-mis-used-weapon/ |website=Just Fly Sports Performance |access-date=7 October 2021}}</ref> L-citrulline boosts nitric oxide production in the body. Nitric oxide helps the arteries relax and work better.<ref>{{cite web |last1=Miller |first1=Kelli |title=L-citrulline: Uses and Risks |url=https://www.webmd.com/vitamins-and-supplements/l-citrulline-uses-and-risks#:~:text=L%2Dcitrulline%20boosts%20nitric%20oxide,treating%20or%20preventing%20some%20diseases. |website=WebMD |access-date=11 October 2021 |language=en}}</ref> ''{{w|Citrullus vulgaris}}'' (watermelon) is the main source.<ref>{{cite web |title=Citrulline Food Sources & Recommended Dietary Intake |url=https://nootriment.com/citrulline-foods/ |website=Nootriment - Health Supplement Reviews and Research |access-date=8 October 2021 |date=30 March 2016}}</ref> 
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| 1915 || Scientific development || Around this time, with advances in knowledge of vitamins, it begins to be understood that some of the virtues of foods come from their contribution of these accessory factors rather than from protein.<ref name="Carpenter"/>
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| 1921 || Scientific development || American scientist {{w|John Howard Mueller}} first isolates {{w|methionine}},<ref>{{Cite web |url=http://www.nasonline.org/publications/biographical-memoirs/memoir-pdfs/mueller-john.pdf |title=A Biographical Memoir of John Howard Mueller |date=1987 |publisher=National Academy of Sciences |location=Washington D.C. |vauthors=Pappenheimer AM}}</ref> an essential amino acid found in many proteins, including those in foods and those found in the tissues and organs of the body.<ref>{{cite web |title=Methionine: Functions, Food Sources and Side Effects |url=https://www.healthline.com/nutrition/methionine#what-it-is |website=Healthline |access-date=4 October 2021 |language=en |date=13 April 2018}}</ref><ref>{{cite journal |last1=Parker |first1=Stewart F. |last2=Funnell |first2=Nicholas P. |last3=Shankland |first3=Kenneth |last4=Kabova |first4=Elena A. |last5=Häußner |first5=Thomas |last6=Hasselbach |first6=Hans-Joachim |last7=Braune |first7=Sascha |last8=Kobler |first8=Christoph |last9=Albers |first9=Peter W. |title=Structure and spectroscopy of methionyl-methionine for aquaculture |journal=Scientific Reports |date=11 January 2021 |volume=11 |issue=1 |pages=458 |doi=10.1038/s41598-020-80385-z |url=https://www.nature.com/articles/s41598-020-80385-z |language=en |issn=2045-2322}}</ref> An antioxidant, {{w|methionine}} may help protect the body from damage caused by ionizing radiation.<ref>{{cite web |title=Methionine - Health Encyclopedia - University of Rochester Medical Center |url=https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=19&contentid=Methionine |website=www.urmc.rochester.edu |access-date=10 October 2021}}</ref> Methionine is abundant in [[w:Turkey (bird)|turkey]], {{w|beef}}, {{w|fish}}, {{w|pork}}, {{w|tofu}}, {{w|milk}}, {{w|cheese}}, {{w|nut}}s, {{w|bean}}s, and {{w|whole grain}}s like {{w|quinoa}}.<ref>{{cite web |title=Top 10 Foods Highest in Methionine |url=https://www.myfooddata.com/articles/high-methionine-foods.php |website=myfooddata |access-date=11 October 2021 |language=english}}</ref>
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| 1923 || Notable comment || {{w|Gregor Mendel}} refers to "the glorification of the albuminous substances" in earlier times, but at the time of writing "the pendulum of enthusiasm about the proteins has swung from one extreme to the other."<ref name="Carpenter"/>
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| 1924 || Scientific development || W. C. Rose and coworkers publish a series of landmark papers on amino acid nutrition and metabolism in rats and humans that further define amino acids as nutritionally essential or nonessential, based on nitrogen balance or growth.<ref>{{cite journal |last1=Hou |first1=Yongqing |last2=Wu |first2=Guoyao |title=Nutritionally Essential Amino Acids |journal=Advances in Nutrition |date=1 November 2018 |volume=9 |issue=6 |pages=849–851 |doi=10.1093/advances/nmy054}}</ref>
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| 1928 || Scientific development || Burger and Coen determine the structure of {{w|methionine}}.<ref>{{cite web |title=LYSINE AND METHIONINE CONTENTS OF DRY-MILLED GRAIN SORGHUM FRACTIONS ALTERED BY YEAST GROWTH |url=https://ttu-ir.tdl.org/bitstream/handle/2346/13196/31295015503419.pdf;sequence=1}}</ref>
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| 1930 || Recommendation || Fishberg recommends protein restriction for uremic patients.<ref name="Byham-Gray">{{cite book |last1=Byham-Gray |first1=Laura D. |last2=Burrowes |first2=Jerrilynn D. |last3=Chertow |first3=Glenn M. |title=Nutrition in Kidney Disease |date=15 May 2008 |publisher=Springer Science & Business Media |isbn=978-1-59745-032-4 |url=https://books.google.com.ar/books?id=uzkeieWipCAC&pg=PA18&lpg=PA18&dq=%22protein%22+%22nutrition%22+%22in+1930%22&source=bl&ots=4-Ht8ECzzb&sig=ACfU3U3tzASUGYzaw6McjqFY65SoFapU_w&hl=en&sa=X&ved=2ahUKEwissaLok_vzAhW0p5UCHVWuA0gQ6AF6BAgXEAM#v=onepage&q=%22protein%22%20%22nutrition%22%20%22in%201930%22&f=false |language=en}}</ref>
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| 1935 || Scientific development || {{w|Jamaica}}n {{w|pediatrician}} {{w|Cicely Williams}} introduces the term {{w|Kwashiorkor}} two years after publishing the disease's first formal description.<ref>{{cite journal |last1=Williams |first1=C D |title=Fifty years ago. Archives of Diseases in Childhood 1933. A nutritional disease of childhood associated with a maize diet. |journal=Archives of Disease in Childhood |date=1 July 1983 |volume=58 |issue=7 |pages=550–560 |doi=10.1136/adc.58.7.550}}</ref><ref>{{cite journal |last1=Williams |first1=CicelyD. |title=KWASHIORKOR |journal=The Lancet |date=November 1935 |volume=226 |issue=5855 |pages=1151–1152 |doi=10.1016/S0140-6736(00)94666-X}}</ref> Kwashiorkor is caused by a lack of protein in the diet.<ref>{{cite web |title=Kwashiorkor: Causes, Symptoms, and Diagnosis |url=https://www.healthline.com/health/kwashiorkor#:~:text=Kwashiorkor%20is%20caused%20by%20a,cells%20in%20this%20way%20constantly. |website=Healthline |access-date=4 October 2021 |language=en |date=15 August 2012}}</ref> 
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| 1936 || Scientific development || {{w|Threonine}} becomes the last of the 20 common {{w|proteinogenic}} amino acids to be discovered. It is discovered by {{w|William Cumming Rose}},<ref>{{Cite book|url=https://books.google.com/books?id=AtngooiwXikC&pg=PA459|title=A Dictionary of scientists.|date=1999|publisher=Oxford University Press|others=Daintith, John., Gjertsen, Derek.|isbn=9780192800862|location=Oxford|pages=459}}</ref> collaborating with Curtis Meyer. The amino acid is named threonine because it is found to be similar in structure to {{w|threonic acid}}, a four-carbon {{w|monosaccharide}} with {{w|molecular formula}} C<sub>4</sub>H<sub>8</sub>O<sub>5</sub><ref>{{cite journal |last1=Meyer |first1=Curtis |title=The Spatial Configuation of Alpha-Amino-Beta-Hydroxy-n-Butyric Acid |journal=Journal of Biological Chemistry |date=20 July 1936 |volume=115 |issue=3 |pages=721–729 |doi=10.1016/S0021-9258(18)74711-X |url=http://www.jbc.org/content/115/3/721.full.pdf}}</ref>
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| 1939 || Scientific development || Walter Kempner at Duke University introduces the {{w|rice diet}}, low-protein diet to treat kidney disease. It consists in a daily ration of 2,000 calories of moderate amounts of boiled rice, sucrose and dextrose, and a restricted range of fruit, supplemented with vitamins. Sodium and chloride are restricted to 150mg and 200mg respectively. The rice diet shows remarkable effects on control of {{w|edema}} and {{w|hypertension}}.<ref>{{cite journal |last1=Kempner |first1=Walter |title=Some Effects of the Rice Diet Treatment of Kidney Disease and Hypertension |journal=Bulletin of the New York Academy of Medicine |volume=22 |issue=7 |pages=358–70 |year=1946 |pmid=19312487 |pmc=1871537 }}</ref><ref>{{cite journal |last1=Kempner |first1=Walter |title=Treatment of hypertensive vascular disease with rice diet |journal=The American Journal of Medicine |volume=4 |issue=4 |pages=545–77 |year=1948 |pmid=18909456 |doi=10.1016/0002-9343(48)90441-0 }}</ref>
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| 1941 || Recommendation || The Recommended Dietary Allowance (RDA) for protein of 0.8g per kilogram of body weight for adults is established.<ref name="Rodriguez">{{cite journal |last1=Rodriguez |first1=Nancy R. |title=Role of Meat in Healthy Eating Patterns: Considerations for Protein Quantity and Protein Quality |journal=Meat and Muscle Biology |date=30 April 2021 |volume=4 |issue=2 |doi=10.22175/mmb.11687 |url=https://iastatedigitalpress.com/mmb/article/id/11687/ |issn=2575-985X}}</ref>
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| 1948 || Literature || Melville Sahyun publishes ''Proteins and Amino Acids in Nutrition'', an early book on the topic.<ref>{{cite book |last1=Sahyun |first1=Melville |title=Proteins and Amino Acids in Nutrition |date=1 March 2007 |publisher=Read Books |isbn=978-1-4067-4730-0 |url=https://books.google.com.ar/books/about/Proteins_and_Amino_Acids_in_Nutrition.html?id=34Ff1fXQIOEC&source=kp_book_description&redir_esc=y |language=en}}</ref>
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| 1948 || Scientific development || Borst reports that a protein-free, normal calorie, low salt diet improves {{w|uremia}} and edema in patients with advanced renal failure.<ref name="Byham-Gray"/>
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| 1949 || Scientific development || The first protein to be [[w:protein sequencing|sequenced]] is {{w|insulin}}, by {{w|Frederick Sanger}}, who correctly determines its amino acid sequence, thus conclusively demonstrating that proteins consist of linear polymers of amino acids rather than branched chains, {{w|colloid}}s, or {{w|cyclol}}s.<ref>{{cite journal |last1=Sanger |first1=F. |title=The terminal peptides of insulin |journal=Biochemical Journal |date=1 January 1949 |volume=45 |issue=5 |pages=563–574 |doi=10.1042/bj0450563}}</ref> Insulin helps regulate blood sugar levels.<ref>{{cite web |title=Diabetes treatment: Using insulin to manage blood sugar |url=https://www.mayoclinic.org/diseases-conditions/diabetes/in-depth/diabetes-treatment/art-20044084#:~:text=The%20role%20of%20insulin%20in%20the%20body&text=If%20you%20don't%20have,Glucose%20then%20enters%20the%20bloodstream. |website=Mayo Clinic |access-date=11 October 2021 |language=en}}</ref>
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| 1950 || Scientific development || Protein becomes a matter of nutritional concern as a result of study of the disease, kwashiorkor in young children (usually 6 mo to 2 yr old) first in Africa and then in Jamaica, Central America and else where. This disease, with a high mortality rate, occurs after weaning onto a bulky, low protein diet, and its onset usually follows a bout with diarrhea.<ref name="Carpenter"/>
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| 1950 || Scientific development || American biochemist {{w|William Cumming Rose}} identifies {{w|methionine}} and {{w|valine}} as nutritionally essential amino acids for young adults.<ref>{{cite journal |last1=Rose |first1=W C |title=II. The sequence of events leading to the establishment of the amino acid needs of man. |journal=American Journal of Public Health and the Nations Health |date=November 1968 |volume=58 |issue=11 |pages=2020–2027 |doi=10.2105/AJPH.58.11.2020}}</ref><ref name="Guoyao">{{cite journal |last1=Wu |first1=Guoyao |title=Dietary protein intake and human health |journal=Food & Function |date=2016 |volume=7 |issue=3 |pages=1251–1265 |doi=10.1039/C5FO01530H}}</ref>
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| 1950–1975 || Focus trend || Around this time, the work of the Nutrition Division of {{w|Food and Agriculture Organization}} is based on the assumption that "deficiency of protein in the diet is the most serious and widespread problem in the world".<ref name="Carpenter"/>
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| 1950–1975 || Focus trend || A downward trend in the successive estimates of protein requirements, particularly for children, occurs over this period.<ref name="Carpenter"/>
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| 1954 || Literature || {{w|Adelle Davis}} publishes ''Let's Eat Right to Keep Fit'', which describes the importance of combining "incomplete" proteins to make "complete" proteins, and advises that any incomplete proteins not complemented within one hour could not be used by the body.<ref>{{cite book|last1=Davis|first1=Adelle|title=Let's Eat Right to Keep Fit|date=1954|publisher=Harcourt, Brace|isbn=4-87187-961-5}}</ref>
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| 1959 || Literature || Anthony Albanese publishes ''Protein and Amino acid nutrition'', which describes the state of knowledge concerning the nutrition of proteins and amino acids.<ref>{{cite book |last1=Albanese |first1=Anthony |title=Protein and Amino acid nutrition |date=2 December 2012 |publisher=Elsevier |isbn=978-0-323-14445-2 |url=https://books.google.com.ar/books/about/Protein_and_Amino_Acid_Nutrition.html?id=4KzisJ39Uz0C&source=kp_book_description&redir_esc=y |language=en}}</ref>
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| 1959 || Scientific development || Mark Hegsted of the Harvard School of Public Health warns that estimated human protein requirements are excessively reliant on non-human animal studies.<ref name="The Conversation">{{cite web |last1=Webb |first1=Geoff |title=The protein gap – nutritional science's biggest error |url=https://theconversation.com/the-protein-gap-nutritional-sciences-biggest-error-76202 |website=The Conversation |access-date=3 November 2021 |language=en}}</ref>
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| 1960 || Recommendation || William C. Rose and Robert L. Wixon from {{w|University of Illinois at Urbana-Champaign}} establish minimum daily requirements of essential amino acids, a discovery made in individuals without kidney disease. This discovery would contribute to the understanding of amino acid metabolism.<ref name="Byham-Gray"/>
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| 1963 || Scientific development || Italian physician Carmelo Giordano applies the concept of high biological value (HBV) protein to the renal diet, in a time when only protein of animal origin is considered HBV. Giordano stresses the need for a specific quality of protein as well as quantity.<ref name="Byham-Gray"/>
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| 1967 || Notable report || The United Nations Advisory Committee on the Application of Science and Technology to Development presents a report to the UN Economic and Social Council entitled 'International action to avert the impending protein crisis'. The preface states that "world food production is falling behind population growth despite all current national, bilateral and international efforts to reverse this trend". Then adds that "adequate protein is also required for the normal maintenance of body tissue and functions, and additionally for growth, maturation, pregnancy, lactation and recovery from injury and disease". The statement continues: "Today there are over 300 million children, who, for lack of sufficient protein and calories suffer grossly retarded physical growth and development, and for many of these, mental development, learning and behaviour may be impaired as well. Protein-calorie deficiencies also directly affect the health and economic productivity of adult populations".<ref name="Gottschalk">{{cite book |last1=Gottschalk |first1=W. |last2=Müller |first2=H. P. |title=Seed Proteins: Biochemistry, Genetics, Nutritive Value |date=3 November 2011 |publisher=Springer Netherlands |isbn=978-94-009-6803-5 |url=https://books.google.co.il/books?id=SR4hnwEACAAJ&hl=iw&source=gbs_book_other_versions_r&cad=4 |language=en}}</ref>
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|-
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| 1968 || Notable prediction || It is predicted that, despite the promise of new technologies in the development of unconventional sources of protein food and feed, crops and livestock would continue to be the major sources of protein for human comsumption.<ref name="Gottschalk"/>
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|-
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| 1968 || Program launch || The {{w|Food and Agriculture Organization}} and the {{w|International Atomic Energy Agency}} establish an International Coordinated Research Program on the Use of Nuclear Techniques for Seed Protein Improvement, following recommendations of a panel of experts.<ref name="Gottschalk"/>
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|-
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| 1969 || Scientific development || Goldman et al. report that high protein intakes (from 6g/kg/day) in low birth weight infants are associated with a condition known as late metabolic acidosis.<ref name="Pencharz">{{cite journal |last1=Pencharz |first1=P B |title=Protein and energy requirements for ‘optimal’ catch-up growth |journal=European Journal of Clinical Nutrition |date=May 2010 |volume=64 |issue=S1 |pages=S5–S7 |doi=10.1038/ejcn.2010.39}}</ref><ref>{{cite journal |title=AMINO ACID REQUIREMENTS OF ADULT MAN |journal=Nutrition Reviews |date=27 April 2009 |volume=14 |issue=8 |pages=232–235 |doi=10.1111/j.1753-4887.1956.tb01591.x}}</ref>
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|-
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| 1971 || Literature || {{w|Frances Moore Lappé}} publishes ''{{w|Diet for a Small Planet}}'', which explains how essential amino acids might be obtained from complementary sources in {{w|vegetarian nutrition}}. This book becomes a {{w|bestseller}}.<ref>{{cite book |last1=Belasco |first1=Warren James |title=Appetite for change : how the counterculture took on the food industry, 1966-1988 |date=1989 |publisher=Pantheon Books |location=New York |isbn=0394543998 |edition=1st}}</ref>
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|-
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| 1971 || Recommendation || The United Nations publishes a document, analyzing the reasons for slow progress in protein food matters and suggesting strategies to avert the protein problem confronting developing countries. Some of these include efforts to balance negative effects of the spread of higher yielding cereal varieties by expanding the 'green revolution' to pulses and oil seed crops, and strengthening the breeding programs for better protein quantity and quality in all important cereals.<ref name="Gottschalk"/>
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|-
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| 1972 || Scientific development || The Protein Advisory Group of the United Nations convenes a symposium at the {{w|Food and Agriculture Organization}}
 +
headquarters in Rome bringing together experts of different fields to review nutritional and food use deficiencies, plant physiology, pathology, and production technology problems which need to be resolved in order to increase the supply of this valuable food item. Six food legumes (dry bean, pigeon pea, cow pea, chickpea, broad bean, pea) and two leguminous oil seeds (peanut, soybean) are identified as priority targets for international and national research efforts.<ref name="Gottschalk"/>
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|-
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| 1973 || Scientific development || {{w|Myosin}} (class I) is discovered in ''{{w|Acanthamoeba}}'' by Pollard and Korn.<ref>{{cite journal |last1=Oosawa |first1=Fumio |title=Discovery of myosin I and Pollard-san |journal=Biophysical Reviews |date=16 November 2018 |volume=10 |issue=6 |pages=1481–1482 |doi=10.1007/s12551-018-0485-5 |url=https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6297091/ |issn=1867-2450}}</ref> Myosin is a diverse superfamily of motor proteins responsible for actin-based motility and contractility in eukaryotic cells.<ref>{{cite journal |last1=Ouyang |first1=Zhaohui |last2=Zhao |first2=Shuangshuang |last3=Yao |first3=Su |last4=Wang |first4=Jing |last5=Cui |first5=Yanqin |last6=Wei |first6=Ke |last7=Jiu |first7=Yaming |title=Multifaceted Function of Myosin-18, an Unconventional Class of the Myosin Superfamily |journal=Frontiers in Cell and Developmental Biology |date=2021 |volume=9 |pages=2 |doi=10.3389/fcell.2021.632445 |url=https://www.frontiersin.org/articles/10.3389/fcell.2021.632445/full |issn=2296-634X}}</ref>
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|-
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| 1975 || Literature || Both [[w:Vogue (magazine)|Vogue]] and {{w|American Journal of Nursing}} carry articles describing the principles and practice of {{w|protein combining}}.<ref>Judith S. Stern (1975) "How to stay well on a vegetarian diet and save money too!", [[w:Vogue (magazine)|Vogue]] 165(2):150,1</ref><ref>Eleanor R. Williams (1975) [https://www.jstor.org/stable/3423700 Making Vegetarian Diets Nutritious], }}w|American Journal of Nursing}} 75(12):2168–73 from {{w|JSTOR}}</ref>
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|-
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| 1975 || Program launch || The {{w|Food and Agriculture Organization}} and the {{w|International Atomic Energy Agency}} jointly organize a seminar in {{w|Sri Lanka}} to specify the needs for grain legume improvement in {{w|South East Asia}} and to consider the contribution that could be expected from widening genetic variability through mutation induction. It is recognized that many of the currently cultivated legume species still possess a number of 'wild type' characteristics that were beneficial during past natural evolution, but hinder the upgrading of grain production under more intensive farming conditions. South East Asia is an area where many vegetarians rely upon pulses as their main protein source.<ref name="Gottschalk"/>
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|-
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| 1978 || Literature || The American Chemical Society Division of Agricultural and Foods Chemistry publishes ''Nutritional Improvement of Food and Feed Proteins''.<ref>{{cite book |last1=Ill.) |first1=Symposium on Improvement of Protein Nutritive Quality of Foods and Feeds (1977, Chicago |last2=Chemistry |first2=American Chemical Society Division of Agricultural and Foods |title=Nutritional Improvement of Food and Feed Proteins |date=October 1978 |publisher=Springer US |isbn=978-0-306-40026-1 |url=https://books.google.com.ar/books/about/Nutritional_Improvement_of_Food_and_Feed.html?id=DqkvAAAAYAAJ&source=kp_book_description&redir_esc=y |language=en}}</ref>
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|-
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| 1979 || Scientific development || Isner publishes a report of 17 deaths associated with low-quality liquid protein VLCD, due to heart-related causes.<ref>{{Cite journal|last1=Isner|first1=J M|last2=Sours|first2=H E|last3=Paris|first3=A L|last4=Ferrans|first4=V J|last5=Roberts|first5=W C|date=December 1979|title=Sudden, unexpected death in avid dieters using the liquid-protein-modified-fast diet. Observations in 17 patients and the role of the prolonged QT interval.|journal=Circulation|volume=60|issue=6|pages=1401–1412|doi=10.1161/01.CIR.60.6.1401|pmid=498466|issn=0009-7322}}</ref> 
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|-
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| 1982 || Scientific development || Rennie et al. (and later Bennet et al. in 1990<ref>{{cite journal |last1=Bennet |first1=W. M. |last2=Connacher |first2=A. A. |last3=Scrimgeour |first3=C. M. |last4=Rennie |first4=M. J. |title=The effect of amino acid infusion on leg protein turnover assessed by L-[15N]phenylalanine and L-[1-13C]leucine exchange |journal=European Journal of Clinical Investigation |date=1990 |volume=20 |issue=1 |pages=41–50 |doi=10.1111/j.1365-2362.1990.tb01789.x |url=https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2362.1990.tb01789.x |language=en |issn=1365-2362}}</ref>) demonstrate that a mixed macronutrient meal is capable of increasing rates of muscle protein synthesis above rates of muscle protein breakdown and that the amino acids contained within the meal are primarily responsible for this increase.<ref>{{cite journal |last1=Rennie |first1=M. J. |last2=Edwards |first2=R. H. T. |last3=Halliday |first3=D. |last4=Matthews |first4=D. E. |last5=Wolman |first5=S. L. |last6=Millward |first6=D. J. |title=Muscle Protein Synthesis Measured by Stable Isotope Techniques in Man: The Effects of Feeding and Fasting |journal=Clinical Science |date=1 December 1982 |volume=63 |issue=6 |pages=519–523 |doi=10.1042/cs0630519 |url=https://portlandpress.com/clinsci/article-abstract/63/6/519/72811/Muscle-Protein-Synthesis-Measured-by-Stable?redirectedFrom=fulltext |issn=0143-5221}}</ref>
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|-
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| 1989 || Literature || C.A. Barth and E. Schlimme publish ''Milk Proteins: Nutritional, Clinical, Functional and Technological Aspects'', which reviews the state of knowledge and progress of research on food proteins, and in particular, milk proteins.<ref>{{cite book |last1=Barth |first1=C. A. |last2=Schlimme |first2=E. |title=Milk Proteins: Nutritional, Clinical, Functional and Technological Aspects |date=1989 |publisher=Steinkopff |isbn=978-3-7985-0786-9 |url=https://books.google.com.ar/books/about/Milk_Proteins.html?id=FSZtAAAAMAAJ&source=kp_book_description&redir_esc=y |language=en}}</ref>
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|-
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| 1990 || Literature || Raul A. Wapnir publishes ''Protein Nutrition and Mineral Absorption'', which presents information regarding the mechanisms of protein absorption under normal and pathologic conditions, in addition to reviewing changes that occur at various stages of life.<ref>{{cite book |last1=Wapnir |first1=Raul A. |title=Protein Nutrition and Mineral Absorption |date=25 September 1990 |publisher=CRC Press |isbn=978-0-8493-5227-0 |url=https://books.google.com.ar/books/about/Protein_Nutrition_and_Mineral_Absorption.html?id=qfKdaCoZS18C&source=kp_book_description&redir_esc=y |language=en}}</ref>
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| 1993 || Policy || The {{w|Protein Digestibility Corrected Amino Acid Score}} (PDCAAS) is adopted by the US Food and Drug Administration (FDA) and the Food and Agricultural Organization of the United Nations/{{w|World Health Organization}} (FAO/WHO) as "the preferred 'best'" method to determine protein quality. These organizations suggest that other methods for evaluating the quality of protein are inferior.<ref name=FAO>[http://www.fao.org/docrep/U5900t/u5900t07.htm Boutrif, E., Food Quality and Consumer Protection Group, Food Policy and Nutrition Division, FAO, Rome: "Recent Developments in Protein Quality Evaluation" ''Food, Nutrition and Agriculture'', Issue 2/3, 1991]</ref>
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| 1994 || Scientific development || Vernon Young and Peter Pellett publish their paper that becomes the definitive contemporary guide to protein metabolism in humans. It also confirms that complementing proteins at meals is totally unnecessary. Thus, people who avoid consuming animal protein do not need to be at all concerned about amino acid imbalances from the plant proteins that make up their usual diets.<ref name="VRYoung">{{cite journal | author=Young VR, Pellett PL | title=Plant proteins in relation to human protein and amino acid nutrition | journal={{w|The American Journal of Clinical Nutrition}} | volume=59 | issue=5&nbsp;Suppl | year=1994 | pages=1203S–1212S | url = http://www.ajcn.org/content/59/5/1203S.long| pmid=8172124 | doi=10.1093/ajcn/59.5.1203s}}</ref>
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| 1994 || Literature || Zdzisław Sikorski, Bonnie Sun Pan, and Fereidoon Shahidi publish ''Seafood Proteins'', a presentation of the state of knowledge on seafood nitrogenous compounds.<ref>{{cite book |last1=SIKORSKI |first1=Zdzisław |last2=Pan |first2=Bonnie Sun |last3=Shahidi |first3=Fereidoon |title=Seafood Proteins |date=1994 |publisher=Springer US |isbn=978-0-412-98481-5 |url=https://books.google.com.ar/books/about/Seafood_Proteins.html?id=u3AZAQAAIAAJ&source=kp_book_description&redir_esc=y |language=en}}</ref> 
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| 1994 || Scientific development || The {{w|Arp2/3 complex}} (Actin Related Protein 2/3 complex) is named after being identified by affinity chromatography from ''[[w:Acanthamoeba|Acanthamoeba castellanii]]''.<ref>{{cite journal |last1=Machesky |first1=L M |last2=Atkinson |first2=S J |last3=Ampe |first3=C |last4=Vandekerckhove |first4=J |last5=Pollard |first5=T D |title=Purification of a cortical complex containing two unconventional actins from Acanthamoeba by affinity chromatography on profilin-agarose. |journal=Journal of Cell Biology |date=1 October 1994 |volume=127 |issue=1 |pages=107–115 |doi=10.1083/jcb.127.1.107}}</ref> The Arp2/3 complex is an essential component of the actin cytoskeleton in eukaryotic cells.<ref>{{cite journal |last1=Dyche Mullins |first1=R |last2=Pollard |first2=Thomas D |title=Structure and function of the Arp2/3 complex |journal=Current Opinion in Structural Biology |date=1 April 1999 |volume=9 |issue=2 |pages=244–249 |doi=10.1016/S0959-440X(99)80034-7 |url=https://www.sciencedirect.com/science/article/abs/pii/S0959440X99800347 |language=en |issn=0959-440X}}</ref> 
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| 1995 || Literature || Clarence B. Ammerman, David P. Baker, and Austin J. Lewis publish ''Bioavailability of Nutrients for Animals: Amino Acids, Minerals, Vitamins'', which attempts to provide information necessary to formulate diets with appropriate amounts of amino acids, minerals, and vitamins.<ref>{{cite book |last1=Ammerman |first1=Clarence B. |last2=Baker |first2=David P. |last3=Lewis |first3=Austin J. |title=Bioavailability of Nutrients for Animals: Amino Acids, Minerals, Vitamins |date=19 July 1995 |publisher=Elsevier |isbn=978-0-08-052787-1 |url=https://books.google.com.ar/books/about/Bioavailability_of_Nutrients_for_Animals.html?id=iWszTfQOpYAC&source=kp_book_description&redir_esc=y |language=en}}</ref>
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| 1995 || Scientific development || Biolo et al. report that {{w|insulin}} therapy improves protein metabolism.<ref>{{cite book |last1=Biolo |first1=G. |last2=Fleming |first2=R. Y. Declan |last3=Wolfe |first3=R. R. |title=Physiologic hyperinsulinemia stimulates protein synthesis and enhances transport of selected amino acids in human skeletal muscle. |date=1 February 1995 |pages=811–819 |url=https://www.jci.org/articles/view/117731 |language=en}}</ref> 
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| 1996 || Scientific development || Mahe et al. report that {{w|soy protein}} contains a greater proportion of nonessential amino acids than {{w|whey}} protein.<ref>{{cite journal |last1=Mahé |first1=S |last2=Roos |first2=N |last3=Benamouzig |first3=R |last4=Davin |first4=L |last5=Luengo |first5=C |last6=Gagnon |first6=L |last7=Gaussergès |first7=N |last8=Rautureau |first8=J |last9=Tomé |first9=D |title=Gastrojejunal kinetics and the digestion of [15N]beta-lactoglobulin and casein in humans: the influence of the nature and quantity of the protein |journal=The American Journal of Clinical Nutrition |date=1 April 1996 |volume=63 |issue=4 |pages=546–552 |doi=10.1093/ajcn/63.4.546}}</ref> 
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| 2000 || Scientific development || The term ''{{w|proteopathy}}'' is first proposed by {{w|Lary Walker}} and Harry LeVine.<ref name="Walker1">{{cite journal | vauthors = Walker LC, LeVine H | title = The cerebral proteopathies | journal = Neurobiology of Aging | volume = 21 | issue = 4 | pages = 559–61 | year = 2000 | pmid = 10924770 | doi = 10.1016/S0197-4580(00)00160-3 }}</ref> It refers to a disease characterized by the production of aberrant conformers of certain proteins that are misfolded and aggregate in a crystallization-like seeding mechanism—changes that lead to a disturbance of their cellular functions and disease.<ref>{{cite web |title=Proteopathy - an overview {{!}} ScienceDirect Topics |url=https://www.sciencedirect.com/topics/neuroscience/proteopathy#:~:text=Proteopathies%20are%20diseases%20characterized%20by,their%20cellular%20functions%20and%20disease. |website=www.sciencedirect.com |access-date=22 October 2021}}</ref>
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| 2000 || Scientific development || Brunton et al. show that the {{w|gut}} has a major effect on amino-acid metabolism.<ref name="Pencharz"/> 
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| 2000 || Scientific development || Bos et al. conclude that milk proteins are of excellent nutritional value as they have a high metabolic utilization by the organism.<ref>{{cite journal |last1=Bos |first1=Cécile |last2=Gaudichon |first2=Claire |last3=Tomé |first3=Daniel |title=Nutritional and Physiological Criteria in the Assessment of Milk Protein Quality for Humans |journal=Journal of the American College of Nutrition |date=1 April 2000 |volume=19 |issue=sup2 |pages=191S–205S |doi=10.1080/07315724.2000.10718068 |url=https://www.tandfonline.com/doi/abs/10.1080/07315724.2000.10718068 |issn=0731-5724}}</ref>
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| 2002 || Recommendation || The U.S. Institute of Medicine sets a Recommended Dietary Allowance (RDA) of 5 mg/kg body weight/day of {{w|Tryptophan}} for adults 19 years and over.<ref name="DRItext">{{cite book | last1 = Institute of Medicine | title = Dietary Reference Intakes for Energy, Carbohydrates, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids | chapter = Protein and Amino Acids | publisher = The National Academies Press | year = 2002 | location = Washington, DC | pages = 589–768 | doi = 10.17226/10490 | isbn = 978-0-309-08525-0 | chapter-url = https://www.nap.edu/read/10490/chapter/12 }}</ref> 
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| 2002 || Notable comment || American physician [[w:John A. McDougall|Dr. John McDougall]] writes a correction to the American Heart Association for a 2001 publication that questions the completeness of plant proteins, and further asserts that "it is impossible to design an amino acid–deficient diet based on the amounts of unprocessed starches and vegetables sufficient to meet the calorie needs of humans."<ref name="McDougall">{{cite journal|last1=McDougall|first1=J|title=Plant foods have a complete amino acid composition|journal=Circulation|date=25 Jun 2002|volume=105|issue=25|page=e197|pmid=12082008|doi=10.1161/01.CIR.0000018905.97677.1F}}</ref> 
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| 2004 || Literature || ''Rickey Y. Yada'' publshes ''Proteins in Food Processing'', which reviews how proteins may be used to enhance the nutritional, textural and other qualities of food products.<ref>{{cite book |last1=Yada |first1=Rickey Y. |title=Proteins in Food Processing |date=13 November 2017 |publisher=Woodhead Publishing |isbn=978-0-08-100729-7 |url=https://books.google.com.ar/books/about/Proteins_in_Food_Processing.html?id=boeZDgAAQBAJ&source=kp_book_description&redir_esc=y |language=en}}</ref>
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| 2005 || Notable comment || Dr. {{w|Joel Fuhrman}} writes:
 +
{{quote|...plant foods have plenty of protein and you do not have to be a nutritional scientist or dietitian to figure out what to eat and you don’t need to mix and match foods to achieve protein completeness.  Any combination of natural foods will supply you with adequate protein, including all eight essential amino acids as well as unessential amino acids.<ref>{{cite book|last1=Fuhrman|first1=Joel|title=Eat to Live|url=https://archive.org/details/eattoliverevolut00fuhr_975|url-access=limited|date=2005|publisher=Little Brown|page=[https://archive.org/details/eattoliverevolut00fuhr_975/page/n142 137]|isbn=9780316735506}}</ref>}}
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| 2005 || Scientific development || Bos et al. show that {{w|wheat}} proteins are the more gluconeogenic because of their high deamination rate and their high {{w|glutamine}} content.<ref>{{cite journal |last1=Bos |first1=Cécile |last2=Juillet |first2=Barbara |last3=Fouillet |first3=Hélène |last4=Turlan |first4=Lucie |last5=Daré |first5=Sophie |last6=Luengo |first6=Catherine |last7=N’tounda |first7=Rufin |last8=Benamouzig |first8=Robert |last9=Gausserès |first9=Nicolas |last10=Tomé |first10=Daniel |last11=Gaudichon |first11=Claire |title=Postprandial metabolic utilization of wheat protein in humans |journal=The American Journal of Clinical Nutrition |date=1 January 2005 |volume=81 |issue=1 |pages=87–94 |doi=10.1093/ajcn/81.1.87 |url=}}</ref> {{w|Gluconeogenesis}} is the metabolic process by which glucose is formed from noncarbohydrate sources, such as {{w|lactate}}, {{w|amino acid}}s, and {{w|glycerol}}.<ref>{{cite web |title=Gluconeogenesis - an overview {{!}} ScienceDirect Topics |url=https://www.sciencedirect.com/topics/neuroscience/gluconeogenesis |website=www.sciencedirect.com |access-date=10 December 2021}}</ref>
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| 2006 || Notable comment || Dr. {{w|T. Colin Campbell}} writes:
 +
{{quote|We now know that through enormously complex metabolic systems, the human body can derive all the essential amino acids from the natural variety of plant proteins that we encounter every day. It doesn’t require eating higher quantities of plant protein or meticulously planning every meal.<ref name="ChinaStudy">{{cite book|last1=Campbell|first1=T. Colin|last2=Campbell|first2=Thomas M.|title=The China Study|url=https://archive.org/details/chinastudymostco00iith|url-access=limited|date=2006|publisher=BenBella Books|isbn=1935251007|page=[https://archive.org/details/chinastudymostco00iith/page/n45 31]}}</ref>}}
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| 2007 || Recommendation || Isotope studies and reappraisal of nitrogen balance literature using nonlinear regression suggest that the WHO 2007 (Report of a Joint WHO/FAO/UNU Expert Consultation, 2007) estimates of adult protein requirements are too low, by a factor of around 30%.<ref name="Pencharz"/>   
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| 2007 || Recommendation || The World Health Organization 2007 Technical Report on protein and amino acid requirements in human nutrition states that the best estimate for a population average requirement is 105 mg nitrogen/kg body weight per day, or 0.66 g protein/kg body weight per day.<ref name="Schönfeldt"/>
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| 2007 || Scientific development || Bauchart et al. report having identified in the stomach effluent a large number of peptides deriving from {{w|actin}} and {{w|myosin}} (the main muscle proteins) after meat or fish consumption.<ref>{{cite journal |last1=Bauchart |first1=Caroline |last2=Morzel |first2=Martine |last3=Chambon |first3=Christophe |last4=Mirand |first4=Philippe Patureau |last5=Reynès |first5=Christelle |last6=Buffière |first6=Caroline |last7=Rémond |first7=Didier |title=Peptides reproducibly released by in vivo digestion of beef meat and trout flesh in pigs |journal=British Journal of Nutrition |date=December 2007 |volume=98 |issue=6 |pages=1187–1195 |doi=10.1017/S0007114507761810 |url=https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/peptides-reproducibly-released-by-in-vivo-digestion-of-beef-meat-and-trout-flesh-in-pigs/E81B5547C5557B6BE1E23F7ED2427F11 |language=en |issn=1475-2662}}</ref> 
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| 2008 || Scientific development || {{w|Pikachurin}} is first discovered in Japan by Shigeru Sato et al. and named after {{w|Pikachu}}, a species of the ''{{w|Pokémon}}'' franchise.<ref>{{cite journal |last1=Sato |first1=Shigeru |last2=Omori |first2=Yoshihiro |last3=Katoh |first3=Kimiko |last4=Kondo |first4=Mineo |last5=Kanagawa |first5=Motoi |last6=Miyata |first6=Kentaro |last7=Funabiki |first7=Kazuo |last8=Koyasu |first8=Toshiyuki |last9=Kajimura |first9=Naoko |last10=Miyoshi |first10=Tomomitsu |last11=Sawai |first11=Hajime |last12=Kobayashi |first12=Kazuhiro |last13=Tani |first13=Akiko |last14=Toda |first14=Tatsushi |last15=Usukura |first15=Jiro |last16=Tano |first16=Yasuo |last17=Fujikado |first17=Takashi |last18=Furukawa |first18=Takahisa |title=Pikachurin, a dystroglycan ligand, is essential for photoreceptor ribbon synapse formation |journal=Nature Neuroscience |date=August 2008 |volume=11 |issue=8 |pages=923–931 |doi=10.1038/nn.2160}}</ref> An {{w|extracellular matrix}}-like {{w|retina}}l {{w|protein}}, its name is inspired by Pikachu's "lightning-fast moves and shocking electric effects".<ref>{{cite journal |title=Lightning-Fast Vision Protein Named After Pikachu |journal=InventorSpot.com |url=http://inventorspot.com/articles/lightningfast_vision_protein_named_after_pikachu_16170 |access-date=10 December 2021 |language=en}}</ref>
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| 2009 || Notable comment || The [[w:Academy of Nutrition and Dietetics|American Dietetic Association]] writes:
 +
{{quote|Plant protein can meet protein requirements when a variety of plant foods is consumed and energy needs are met. Research indicates that an assortment of plant foods eaten over the course of a day can provide all essential amino acids and ensure adequate nitrogen retention and use in healthy adults, thus, complementary proteins do not need to be consumed at the same meal.<ref>{{cite journal|title=Position of the American Dietetic Association: Vegetarian Diets|journal=Journal of the American Dietetic Association|date=July 2009|volume=109|issue=7|pages=1267–1268|url=http://www.vrg.org/nutrition/2009_ADA_position_paper.pdf|access-date=13 January 2017|doi=10.1016/j.jada.2009.05.027|pmid=19562864 | last1 = Craig | first1 = WJ | last2 = Mangels | first2 = AR}}</ref> }}
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| 2010 || Scientific development || A study from the {{w|University of Copenhagen}} concludes that protein requirements should be based on criteria related to long-term health and well-being, rather than on nitrogen balance alone.<ref>{{cite journal |last1=Jakobsen |first1=Lene H. |last2=Kondrup |first2=Jens |last3=Zellner |first3=Maria |last4=Tetens |first4=Inge |last5=Roth |first5=Erich |title=Effect of a high protein meat diet on muscle and cognitive functions: A randomised controlled dietary intervention trial in healthy men |journal=Clinical Nutrition |date=June 2011 |volume=30 |issue=3 |pages=303–311 |doi=10.1016/j.clnu.2010.12.010}}</ref><ref name="Schönfeldt">{{cite journal |last1=Schönfeldt |first1=Hettie Carina |last2=Hall |first2=Nicolette Gibson |title=Dietary protein quality and malnutrition in Africa |journal=British Journal of Nutrition |date=August 2012 |volume=108 |issue=S2 |pages=S69–S76 |doi=10.1017/S0007114512002553 |url=https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/dietary-protein-quality-and-malnutrition-in-africa/B77459A0CE379BADA38C184AE518ACD7 |language=en |issn=0007-1145}}</ref>
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|-
 +
| 2011 || Scientific development || A review concludes that a "long-term effect of {{w|high-protein diet}}s is neither consistent nor conclusive."<ref>Lepe M, Bacardi Gascon M, Jimenez Cruz. (2011). ''A: Long-term efficacy of high-protein diets: a systematic review''. ''Nutr Hosp'' 26: 1256-1259.</ref> 
 +
|-
 +
| 2011 || Literature || G. O. Phillips and P. A. Williams publish their ''Handbook of Food Proteins'', which provides an overview of the characteristics, functionalities and applications of different proteins of importance to the food industry.<ref>{{cite book |last1=Phillips |first1=G. O. |last2=Williams |first2=P. A. |title=Handbook of Food Proteins |date=9 September 2011 |publisher=Elsevier |isbn=978-0-85709-363-9 |url=https://books.google.com.ar/books/about/Handbook_of_Food_Proteins.html?id=43pwAgAAQBAJ&source=kp_book_description&redir_esc=y |language=en}}</ref> 
 +
|-
 +
| 2011 || Scientific development || Rubinsztein et al. report that {{w|autophagy}} eliminates protein aggregates that are toxic to the cell, thus mediating {{w|cytoprotection}}.<ref>{{cite journal |last1=Rubinsztein |first1=David C. |last2=Mariño |first2=Guillermo |last3=Kroemer |first3=Guido |title=Autophagy and aging |journal=Cell |date=2 September 2011 |volume=146 |issue=5 |pages=682–695 |doi=10.1016/j.cell.2011.07.030 |url=https://pubmed.ncbi.nlm.nih.gov/21884931/ |issn=1097-4172}}</ref> 
 +
|-
 +
| 2012 || Scientific development || Study shows that exercise regulates {{w|protein synthesis}}.<ref>{{cite journal |last1=Pasiakos |first1=S. M. |last2=McClung |first2=H. L. |last3=McClung |first3=J. P. |last4=Margolis |first4=L. M. |last5=Andersen |first5=N. E. |last6=Cloutier |first6=G. J. |last7=Pikosky |first7=M. A. |last8=Rood |first8=J. C. |last9=Fielding |first9=R. A. |last10=Young |first10=A. J. |title=Leucine-enriched essential amino acid supplementation during moderate steady state exercise enhances postexercise muscle protein synthesis |journal=American Journal of Clinical Nutrition |date=1 September 2011 |volume=94 |issue=3 |pages=809–818 |doi=10.3945/ajcn.111.017061 |url=}}</ref> 
 +
|-
 +
| 2013 || Scientific development || Bollwein et al. report that protein intake may be more evenly distributed throughout the day in the frail elderly population than in healthy adults.<ref>{{cite journal |last1=Bollwein |first1=Julia |last2=Diekmann |first2=Rebecca |last3=Kaiser |first3=Matthias J. |last4=Bauer |first4=Jürgen M. |last5=Uter |first5=Wolfgang |last6=Sieber |first6=Cornel C. |last7=Volkert |first7=Dorothee |title=Distribution but not amount of protein intake is associated with frailty: a cross-sectional investigation in the region of Nürnberg |journal=Nutrition Journal |date=5 August 2013 |volume=12 |pages=109 |doi=10.1186/1475-2891-12-109 |url=https://pubmed.ncbi.nlm.nih.gov/23915061/ |issn=1475-2891}}</ref> 
 +
|-
 +
| 2014 || Scientific development || A review notes that high-protein diets from animal sources should be handled with caution.<ref>Schwingshackl, L., & Hoffmann, G. (2014). [https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0097656 ''Comparison of high vs normal/low protein diets on renal function in subjects without chronic kidney disease: a systematic review and meta-analysis'']. PLoS One 9(5): e97656.</ref> 
 +
|-
 +
| 2014 || Scientific development || Researchers report that resistance in older people to [[w:Prandial|postprandial]] anabolic stimulation by dietary protein can be overcome by supplying daily protein in the form of protein-rich meals.<ref>{{cite journal |last1=Paddon-Jones |first1=Douglas |last2=Rasmussen |first2=Blake B. |title=Dietary protein recommendations and the prevention of sarcopenia |journal=Current Opinion in Clinical Nutrition and Metabolic Care |date=January 2009 |volume=12 |issue=1 |pages=86–90 |doi=10.1097/MCO.0b013e32831cef8b |url=https://pubmed.ncbi.nlm.nih.gov/19057193/ |issn=1473-6519}}</ref><ref>{{cite journal |last1=Rodriguez |first1=Nancy R. |title=Protein-Centric Meals for Optimal Protein Utilization: Can It Be That Simple? |journal=The Journal of Nutrition |date=1 June 2014 |volume=144 |issue=6 |pages=797–798 |doi=10.3945/jn.114.193615 |url=}}</ref>
 +
|-
 +
| 2015 || Recommendation || Layman et al. recommend daily allowance for dietary protein intake by an adult person at 0.8 g/kg per day, irrespective of overall energy intake.<ref>{{cite journal |last1=Layman |first1=Donald K |last2=Anthony |first2=Tracy G |last3=Rasmussen |first3=Blake B |last4=Adams |first4=Sean H |last5=Lynch |first5=Christopher J |last6=Brinkworth |first6=Grant D |last7=Davis |first7=Teresa A |title=Defining meal requirements for protein to optimize metabolic roles of amino acids |journal=The American Journal of Clinical Nutrition |date=1 June 2015 |volume=101 |issue=6 |pages=1330S–1338S |doi=10.3945/ajcn.114.084053}}</ref> 
 +
|-
 +
| 2015–2020 || Recommendation || The ''2015–2020 Dietary Guidelines for Americans'' (DGA) recommends that men and teenage boys increase their consumption of fruits, vegetables and other under-consumed foods, and that a means of accomplishing this would be to reduce overall intake of protein foods.<ref>{{cite web |title=A Closer Look at Current Intakes and Recommended Shifts - 2015-2020 Dietary Guidelines - health.gov |url=https://web.archive.org/web/20160109170222/http://health.gov/dietaryguidelines/2015/guidelines/chapter-2/a-closer-look-at-current-intakes-and-recommended-shifts/ |website=web.archive.org |access-date=4 October 2021 |date=9 January 2016}}</ref>
 +
|-
 +
| 2016 || Notable comment || The {{w|American Heart Association}} states:
 +
{{quote|You don’t need to eat foods from animals to have enough protein in your diet. Plant proteins alone can provide enough of the essential and non-essential amino acids, as long as sources of dietary protein are varied and caloric intake is high enough to meet energy needs. Whole grains, legumes, vegetables, seeds and nuts all contain both essential and non-essential amino acids. You don’t need to consciously combine these foods (“complementary proteins”) within a given meal.<ref>[https://www.heart.org/HEARTORG/HealthyLiving/HealthyEating/NutritionDiets_UCM_306032_Article.jsp Vegetarian Diets] American Heart Association, Sep 26, 2016</ref>}}
 +
|-
 +
| 2017 || Scientific development || A review indicates that a high-protein diet may contribute to life-long risk of kidney damage, including {{w|chronic kidney disease}}.<ref>{{cite journal |last1=Kalantar-Zadeh |first1=Kamyar |last2=Fouque |first2=Denis |title=Nutritional Management of Chronic Kidney Disease |journal=New England Journal of Medicine |date=2 November 2017 |volume=377 |issue=18 |pages=1765–1776 |doi=10.1056/NEJMra1700312}}</ref> 
 +
|-
 +
| 2020 || Scientific development || A review finds that a high-protein diet does not significantly improve blood pressure and [[w:glucose|glycemic control]] in people with {{w|diabetes}}.<ref>{{cite journal |last1=Yu |first1=Zhangping |last2=Nan |first2=Fengwei |last3=Wang |first3=Leslie Yingzhijie |last4=Jiang |first4=Hua |last5=Chen |first5=Wei |last6=Jiang |first6=Yu |title=Effects of high-protein diet on glycemic control, insulin resistance and blood pressure in type 2 diabetes: A systematic review and meta-analysis of randomized controlled trials |journal=Clinical Nutrition |date=June 2020 |volume=39 |issue=6 |pages=1724–1734 |doi=10.1016/j.clnu.2019.08.008}}</ref> 
 +
|-
 +
|}
 +
 
 +
== Tabular and visual data  ==
 +
 
 +
The table below shows daily protein intake (g) by age, education, work, status, income and geographical region, in Chinese women from 1991 to 2015.<ref>{{cite journal |last1=Zhao |first1=Jian |last2=Su |first2=Chang |last3=Wang |first3=Huijun |last4=Wang |first4=Zhihong |last5=Wang |first5=Yun |last6=Zhang |first6=Bing |title=Secular Trends in Energy and Macronutrient Intakes and Distribution among Adult Females (1991–2015): Results from the China Health and Nutrition Survey |journal=Nutrients |date=24 January 2018 |volume=10 |issue=2 |pages=115 |doi=10.3390/nu10020115}}</ref>
 +
 
 +
{| class="sortable wikitable"
 +
!
 +
! 1991 Mean
 +
! 1991 SE
 +
! 1993 Mean
 +
! 1993 SE
 +
! 1997 Mean
 +
! 1997 SE
 +
! 2000 Mean
 +
! 2000 SE
 +
! 2004 Mean
 +
! 2004 SE
 +
! 2006 Mean
 +
! 2006 SE
 +
! 2009 Mean
 +
! 2009 SE
 +
! 2011 Mean
 +
! 2011 SE
 +
! 2015 Mean
 +
! 2015 SE
 +
|-
 +
| '''Age group (year):'''
 +
|-
 +
| 18-49 || 70.3 || 0.4 || 69.9 || 0.4 || 67.9 || 0.4 || 65.7 ||0.4 || 65.0 || 0.4 || 65.2 || 0.4 || 63.9 || 0.4 || 61.0 || 0.4 || 57.7 || 0.4
 +
|-
 +
| 50-64 || 67.7 || 0.7 || 66.3 || 0.9 || 63.6 || 0.8 || 63.9 || 0.7 || 64.8 || 0.7 || 64.6 || 0.6 || 62.4 || 0.6 || 59.0 || 0.5 || 56.2 || 0.4
 +
|-
 +
| '''Education level:'''
 +
|-
 +
| Primary/ illiterate || 69.6 || 0.5 || 68.9 || 0.5 || 66.0 || 0.5 || 63.7 || 0.5 || 64.1 || 0.5 || 64.5 || 0.5 || 62.7 || 0.5 || 58.0 || 0.5 || 57.0 || 0.5
 +
|-
 +
| Middle school || 69.9 || 0.6 || 69.8 || 0.7 || 67.9 || 0.6 || 66.3 || 0.6 || 64.2 || 0.6 || 65.6 || 0.6 || 63.9 || 0.5 || 60.8 || 0.5 || 58.2 || 0.6
 +
|-
 +
| High/above || 70.4 || 0.8 || 69.9 || 0.9 || 68.7 || 0.8 || 67.0 || 0.7 || 67.3 || 0.7 || 64.9 || 0.7 || 63.8 || 0.7 || 62.2 || 0.6 || 56.3 || 0.4
 +
|-
 +
| '''Income:'''
 +
|-
 +
| Low || 68.9 || 0.6 || 68.7 || 0.6 || 65.7 || 0.6 || 64.0 || 0.6 || 62.7 || 0.6 || 64.9 || 0.6 || 63.0 || 0.5 || 59.8 || 0.5|| 55.7 || 0.5
 +
|-
 +
| Medium || 70.0 || 0.6 || 69.1 || 0.6 || 67.7 || 0.6 || 64.9 || 0.6 || 66.2 || 0.6 || 65.2 || 0.6 || 63.1 || 0.6 || 59.4 || 0.5 || 55.9 || 0.5
 +
|-
 +
| High || 70.5 || 0.6 || 70.3 || 0.6 || 67.7 || 0.6 || 67.0 || 0.6 || 65.9 || 0.6 || 65.0 || 0.6 || 64.1 || 0.5 || 61.5 || 0.5 || 59.2 || 0.5
 +
|-
 +
| '''Region:''' 
 +
|-
 +
| Rural || 69.6 || 0.5 || 70.4 || 0.6 || 69.7 || 0.6 || 67.8 || 0.6 || 66.8 || 0.6 || 66.6 || 0.7 || 64.0 || 0.6 || 61.3 || 0.5 || 55.4 || 0.3
 +
|-
 +
| Urban || 69.9 || 0.4 || 68.8 || 0.4 || 65.8 || 0.4 || 64.1 || 0.4 || 64.1 || 0.4 || 64.3 || 0.4 || 63.2 || 0.4 || 59.7 || 0.3 || 59.5 || 0.4 
 +
|-
 +
| '''BMI category:'''   
 +
|-
 +
| Underweight || 64.9 || 1.1 || 67.3 || 1.2 || 63.8 || 1.2 || 63.5 || 1.4 || 63.9 || 1.5 || 62.5 || 1.4 || 59.2 || 1.1 || 59.0 || 1.2 || 56.3 || 1.0
 +
|-
 +
| Normal || 69.9 || 0.4 || 68.9 || 0.4 || 66.9 || 0.4 || 65.5 || 0.4 || 64.6 || 0.5 || 64.7 || 0.4 || 63.6 || 0.4 || 60.6 || 0.4|| 57.0 || 0.4 
 +
|-
 +
| Overweight/ obesity || 71.5 || 0.7 || 71.3 || 0.7 || 68.3 || 0.7 || 65.2 || 0.6 || 65.8 || 0.6 || 66.1 || 0.6 || 63.9 || 0.5 || 60.0 || 0.5 || 57.2 || 0.4 
 +
|-
 +
| Total || 69.8 || 0.3 || 69.3 || 0.4 || 67.1 || 0.3 || 65.3 || 0.3 || 64.9 || 0.4 || 65.0 || 0.3 || 63.4 || 0.3 || 60.3 || 0.3 || 57.0 || 0.3 
 +
|-
 +
|}
 +
 
 +
The table below shows changing views of the role of amino acids in human nutrition.<ref>{{cite journal |last1=Dupont |first1=Christophe |title=Protein requirements during the first year of life |journal=The American Journal of Clinical Nutrition |date=1 June 2003 |volume=77 |issue=6 |pages=1544S–1549S |doi=10.1093/ajcn/77.6.1544S}}</ref>
 +
 
 +
{| class="sortable wikitable"
 +
! 1954 Indispensable
 +
! 1994 Indispensable
 +
! 1994 Conditionally indispensable
 +
! 1954 Dispensable
 +
! 1994 Dispensable
 +
|-
 +
| {{w|Valine}} || {{w|Valine}} || {{w|Glycine}} || {{w|Glycine}} || {{w|Glutamic acid}} 
 +
|-
 +
| {{w|Isoleucine}} || {{w|Isoleucine}} || {{w|Cystine}} || {{w|Cystine}} || {{w|Alanine}} 
 +
|-
 +
| {{w|Leucine}} || {{w|Leucine}} || {{w|Glutamine}} || {{w|Glutamic acid}} || {{w|Serine}}
 +
|-
 +
| {{w|Lysine}} || {{w|Lysine}} || {{w|Tyrosine}} || {{w|Tyrosine}} || {{w|Aspartic acid}} 
 +
|-
 +
| {{w|Methionine}} || {{w|Methionine}} || {{w|Proline}} || {{w|Proline}} || {{w|Asparagine}}
 +
|-
 +
| {{w|Phenylalanine}} || {{w|Phenylalanine}} || {{w|Arginine}} || {{w|Arginine}} ||
 +
|-
 +
| {{w|Threonine}} || {{w|Threonine}} || {{w|Taurine}} || {{w|Alanine}} ||
 +
|-
 +
| {{w|Tryptophan}} || {{w|Tryptophan}} || || {{w|Serine}}  ||
 +
|-
 +
| || {{w|Histidine}} || || {{w|Aspartic acid}} ||
 +
|-
 +
| || || || {{w|Histidine}} ||
 +
|-
 +
| || || || {{w|Hydroxyproline}} ||
 +
|-
 +
| || || || {{w|Citrulline}} ||
 +
|-
 +
 
 +
|}
 +
 
 +
 
 +
The table below shows estimates made at different times of the protein and energy requirements of children at 1 year of age.<ref name="Carpenter"/>
 +
 
 +
{| class="sortable wikitable"
 +
! Year
 +
! Protein
 +
! Energy
 +
! Protein energy
 +
! Source
 +
|-
 +
| || g/kg body wt || kcal/kg body wt || % of total energy ||
 +
|-
 +
| 1948 || 3.3 || 100 || 13.2 || {{w|USA}}
 +
|-
 +
| 1957 || 2.0 || 100 || 8.0 || {{w|FAO}}
 +
|-
 +
| 1964 || 2.5 || 100 || 10.0 || {{w|USA}}
 +
|-
 +
| 1965 || 1.1 || 100 || 4.4 || {{w|FAO}}/{{w|WHO}}
 +
|-
 +
| 1968 || 1.8 || 100 || 7.2 || {{w|USA}}
 +
|-
 +
| 1969 || 1.3 || 110 || 4.7 || {{w|UK}}
 +
|-
 +
| 1973 || 1.27 || 105 || 4.8 || {{w|FAO}}/{{w|WHO}}
 +
|-
 +
| 1974 || 1.35 || 100 || 5.4 || {{w|USA}}
 
|-
 
|-
 
|}
 
|}
 +
 +
=== Google Schoolar ===
 +
 +
The following table summarizes per-year mentions on Google Scholar as of October 3, 2021.
 +
 +
{| class="sortable wikitable"
 +
! Year
 +
! "protein"
 +
|-
 +
| 1900 || 405
 +
|-
 +
| 1910 || 925
 +
|-
 +
| 1920 || 1,910
 +
|-
 +
| 1930 || 3,360
 +
|-
 +
| 1940 || 5,070
 +
|-
 +
| 1950 || 9,590
 +
|-
 +
| 1960 || 21,100
 +
|-
 +
| 1970 || 64,500
 +
|-
 +
| 1980 || 170,000
 +
|-
 +
| 1990 || 472,000
 +
|-
 +
| 2000 || 1,110,000 
 +
|-
 +
| 2010 || 1,600,000
 +
|-
 +
| 2020 || 274,000
 +
|-
 +
|}
 +
 +
[[File:Protein gsch.png|thumb|center|700px]]
 +
 +
The table below shows dietary requirements of protein (g per kg body weight per day).<ref name="Dietfoo">{{cite web |last1=Wu |first1=Guoyao |title=Dietary protein intake and human health |url=https://pubs.rsc.org/en/content/articlehtml/2016/fo/c5fo01530h#cit18 |website=Food & Function |access-date=19 October 2021 |pages=1251–1265 |language=en |doi=10.1039/C5FO01530H |date=2016}}</ref>
 +
 +
{| class="sortable wikitable"
 +
! Group
 +
! Age (Years)
 +
! IOM 2005
 +
! FAO/ WHO/ UNU 1985
 +
! FAO/ WHO/ UNU 2007
 +
|-
 +
| Infants || 0.3-0.5 || 1.52 || 1.75 || 1.31
 +
|-
 +
| || 0.75-1.0 || 1.50 || 1.57 || 1.14
 +
|-
 +
| Children || 1-3 || 1.10 || 1.18 || 1.02
 +
|-
 +
| || 4-8 || 0.95 || 1.05 || 0.92
 +
|-
 +
| Adolescents || 9-13 || 0.95 || 0.99 || 0.90
 +
|-
 +
| || 14-18 (boys) || 0.85 || 0.97 || 0.87
 +
|-
 +
| || 14-18 (girl) || 0.85 || 0.94 || 0.85
 +
|-
 +
| Adults || >19 || 0.80|| 0.75 || 0.83
 +
|-
 +
|}
 +
 +
 +
The table below shows dietary requirements of essential amino acids by healthy human adults.<ref name="Dietfoo"/>
 +
 +
{| class="sortable wikitable"
 +
! EAA
 +
! Estimates from N balance experiments Men
 +
! Estimates from N balance experiments Women
 +
! MIT values (tracer studies) (2000)
 +
! IOM (2005)
 +
! FAO/ WHO UNU (2007)
 +
|-
 +
| His || - || - || - || 14 || 10
 +
|-
 +
| Ile || 10 || 9.17 || 23 || 19 || 20
 +
|-
 +
| Leu || 15.7  || 12.1 || 40 || 42 || 39
 +
|-
 +
| Lys || 11.4 || 9.07 || 30 || 38 || 30
 +
|-
 +
| Met || 2.36 || 3.23 || - || - || -
 +
|-
 +
| Met+Cys || 15.7 || 11.7 || 13 || 19 || 15
 +
|-
 +
| Phe || 4.29 || 4.30 || - || - || -
 +
|-
 +
| Phe+Tyr || 15.7 || - || 39 || 33 || 25
 +
|-
 +
| Thr || 7.14 || 6.25 || 15 || 20 || 15
 +
|-
 +
| Trp || 3.57 || 2.80 || 6 || 5 || 4
 +
|-
 +
| Val || 11.4 || 10.4 || 20 || 24 || 26
 +
|-
 +
| Total || 90.6 || 65.8 || 186 || 214 || 184
 +
|-
 +
|}
 +
 +
 +
 +
=== Google Trends ===
 +
 +
The comparative chart below shows {{w|Google Trends}} data for Protein (Nutrient) and Protein (Topic) from January 2004 to October 2021, when the screenshot was taken. Interest is also ranked by country and displayed on world map.<ref>{{cite web |title=Protein |url=https://trends.google.com/trends/explore?date=all&q=%2Fm%2F0b7mvf3,%2Fm%2F05wvs |website=Google Trends |access-date=3 October 2021}}</ref>
 +
 +
[[File:Protein gt.png|thumb|center|600px]]
 +
 +
=== Google Ngram Viewer ===
 +
 +
The comparative chart below shows {{w|Google Ngram Viewer}} data for Protein, amino acid and calorie from 1800 to 2019.<ref>{{cite web |title=Protein, amino acid and calorie |url=https://books.google.com/ngrams/graph?content=protein%2Camino+acid%2C+calorie&year_start=1800&year_end=2019&corpus=26&smoothing=3&direct_url=t1%3B%2Cprotein%3B%2Cc0%3B.t1%3B%2Camino%20acid%3B%2Cc0%3B.t1%3B%2Ccalorie%3B%2Cc0#t1%3B%2Cprotein%3B%2Cc0%3B.t1%3B%2Camino%20acid%3B%2Cc0%3B.t1%3B%2Ccalorie%3B%2Cc0 |website=books.google.com |access-date=3 October 2021 |language=en}}</ref>
 +
 +
[[File:Protein ngram.png|thumb|center|700px]]
 +
 +
=== Wikipedia Views ===
 +
 +
The chart below shows pageviews of the English Wikipedia article {{w|Protein}}, from July 2015 to September 2021.<ref>{{cite web |title=Protein |url=https://wikipediaviews.org/displayviewsformultiplemonths.php?page=Protein+%28nutrition%29&allmonths=allmonths-api&language=en&drilldown=all |website=wikipediaviews.org |access-date=3 October 2021}}</ref>
 +
 +
[[File:Protein wv.png|thumb|center|550px]]
 +
  
 
==Meta information on the timeline==
 
==Meta information on the timeline==
Line 23: Line 516:
 
===How the timeline was built===
 
===How the timeline was built===
  
The initial version of the timeline was written by [[User:FIXME|FIXME]].
+
The initial version of the timeline was written by [[User:Sebastian]].
  
 
{{funding info}} is available.
 
{{funding info}} is available.
Line 35: Line 528:
 
===What the timeline is still missing===
 
===What the timeline is still missing===
  
* [https://pubmed.ncbi.nlm.nih.gov/3528432/]
+
* {{w|Category:Proteins as nutrients}}
* [https://pubmed.ncbi.nlm.nih.gov/4626900/]
+
* {{w|Complete protein}}
* [https://pubmed.ncbi.nlm.nih.gov/19892133/]
+
* {{w|List of proteins}}
 +
* {{w|Protein (nutrient)}}
  
 
===Timeline update strategy===
 
===Timeline update strategy===
  
 
==See also==
 
==See also==
 +
 +
* [[Timeline of fats]]
 +
* [[Timeline of malnutrition]]
 +
* [[Timeline of vegetarianism and veganism]]
  
 
==External links==
 
==External links==

Latest revision as of 19:57, 8 April 2024

This is a timeline of proteins, a class of macromolecules in the form of polymer chains made of amino acids. Proteins are essential nutrients for the human body. This timeline focuses on proteins from a nutritional perspective.

Sample questions

The following are some interesting questions that can be answered by reading this timeline:

  • What are some notable scientific events related to the nutritional aspects of proteins?
    • Sort the full timeline by "Event type" and look for the group of rows with value "Scientific development".
  • What are some notable reviews expressed by experts and competent entities?
    • Sort the full timeline by "Event type" and look for the group of rows with value "Notable comment".
    • You will read reviews by both known experts in the field and organizations, such as the American Dietetic Association.
  • What are some notable recommendations of protein intake issued by competent entities?
    • Sort the full timeline by "Event type" and look for the group of rows with value "Recommendation".
    • You will see recommendations from both experts and important organizations, such as WHO ans FAO.
  • What are some notable publications specialized in proteins?
    • Sort the full timeline by "Event type" and look for the group of rows with value "Literature".
  • Other events are described under the following types: "Focus trend", "Notable report", "Policy", and "Program launch".

Big picture

Time period Development summary More details
1920–1950 Relegated attention Around this time, nutritional research centers on the discovery of individual vitamins and amino acids, putting little interest in human protein requirements, or in the possibility of their not being met.[1]
1950s–1960s Mainstream focus Protein again receives priority attention, with United Nations (UN) agencies being focused on protein malnutrition as the major worldwide nutritional problem.[2] The "World Protein Gap" is considered the major cause of infant mortality and retarded development in the Third World but a problem that could be solved by the application of sophisticated technology.[1] From the 1950s to the mid-1970s, United Nations (UN) agencies were focused on protein malnutrition as the major worldwide nutritional problem.
1970s Focus decline United Nations agencies start suspecting about a "protein gap". In the mid-decade, protein malnutrition is suddenly discarded, putting end to years of agencies and international conferences focusing on protein malnutrition.[2]

Full timeline

Year Event type Details
1806 Scientific development French chemists Louis Nicolas Vauquelin and Pierre Jean Robiquet first isolate asparagine in a crystalline form from asparagus juice.[3][4] A non-essential amino acid in humans[5], it is closely related to aspartic acid.[6] Research shows that L-asparagine is able to protect cancer cells from dying due to a loss of glutamine.[7] Rich food sources include dairy, whey, beef, poultry, eggs, fish, seafood, asparagus, potatoes, legumes, nuts, seeds, soy, and whole grains. Poor food sources include most fruits and vegetables.[8]
1810 Scientific development English chemist William Hyde Wollaston indirectly discovers cystine, when managing to isolate a crystalline substance from urinary calculi (kidney stones) and calls it “cystic oxide”.[9] Cystine is the oxidized dimer form of the amino acid cysteine It is a non-essential amino acid important for making protein, and for other metabolic functions.[10]
1816 Scientific development French physiologist François Magendie demonstrates that dogs would die if fed nothing but carbohydrates or fat, i.e., the principal nonnitrogenous food components.[1]
1819 Scientific development The discovery of leucine is attributed to French chemist Joseph Proust who reports its separation from fermented milk curds.[11] Leucine is one of the three branched-chain amino acids (BCAA), along with isoleucine and valine.[12] Like valine, leucine is critical for protein synthesis and muscle repair.[13] Rich food sources include chicken, beef, pork, fish (tuna), tofu, canned beans, milk, cheese, squash seeds, and eggs.[14]
1820 Scientific development Glycine is discovered by French chemist Henri Braconnot when he hydrolyzes gelatin by boiling it with sulfuric acid.[15] Glycine is the main amino acid in collagen, the most abundant protein in the body.[16] It is structural of connective tissue, such as bone, skin, ligaments, tendons and cartilage.[17][18] Glycine is found in high-protein foods including meat, fish, eggs, dairy and legumes.[19]
1827 Scientific development Aspartic acid (or aspartate) is first discovered by Auguste-Arthur Plisson and Étienne Ossian Henry.[20] It is a non-essential amino acid, meaning that it is readily and naturally synthesized by mammals.[21] D-aspartic acid (D-AA) regulates testosterone synthesis and may act on a stimulatory receptor (NMDA).[22]
1827 Scientific development Taurine is first isolated from ox bile by German scientists Friedrich Tiedemann and Leopold Gmelin.[23] It is a type of chemical called an amino sulfonic acid. It occurs naturally in the human body.[24] Taurine is found naturally in meat, fish, dairy products and human milk, and it's also available as a dietary supplement.[25]
1833 Scientific development The empirical formula for asparagine is first determined by French chemists Antoine François Boutron Charlard and Théophile-Jules Pelouze. In the same year, German chemist Justus Liebig provides a more accurate formula.[26][27]
1846 Scientific development English industrial chemist Edmund Ronalds discovers taurine in human bile.[28]
1846 Scientific development Tyrosine is first discovered by German chemist Justus von Liebig in the protein casein from cheese.[29][30] It is one of the 20 standard amino acids that are used by cells to synthesize proteins.[31] Tyrosine is an essential amino acid.[32] It is used to improve alertness, attention and focus.[31] Sources include soy products, chicken, turkey, fish, peanuts, almonds, avocados, bananas, milk, cheese, yogurt, cottage cheese, lima beans, pumpkin seeds, and sesame seeds.[33]
1858 Scientific development French chemist Auguste Cahours determines that glycine is an amine of acetic acid.[34]
1859 Scientific development German scientists Nikolaus Friedreich and Friedrich August Kekulé von Stradonitz demonstrate that, rather than consisting of cellulose, "amyloid" actually is rich in protein.[35]
1865 Scientific development Serine is first obtained by Emil Cramer from silk protein, a particularly rich source. Its name is derived from the Latin for silk, sericum.[36] Serine comes in two forms: L-serine and D-serine.[37] D-serine is used for schizophrenia, cognitive function, and other conditions.[38] It is found in soybeans, nuts (especially peanuts, almonds, and walnuts), eggs, chickpeas, lentils, meat, and fish (especially shellfish).[39]
1866 Scientific development Glutamic acid is discovered and identified by German chemist Karl Heinrich Ritthausen.[40] It is a non-essential amino acid that occurs in plants and animals and is formed via protein metabolism.[41]
1869 Scientific development German scientists Johannes Wislicenus and Adolf Eugen Fick conduct an experiment in which they measure their urinary nitrogen during and after climbing a Swiss mountain, seeming to demonstrate conclusively that there is no apparent extra breakdown of protein that would be required to provide the energy used in the climb.[1]
1879 Scientific development German chemist Ernst Schulze and Johann Barbieri first identify phenylalanine as a constituent of plant proteins.[42][43][44] Phenylalanine is one of the nine essential amino acids. It occurs naturally in many protein-rich foods, such as milk, eggs and meat.[45]
1882 Scientific development German chemists Emil Erlenmeyer and Andreas Lipp first synthesize phenylalanine from phenylacetaldehyde, hydrogen cyanide, and ammonia.[46]
1883 Scientific development German chemists Ernst Schulze and E. Bosshard isolate L-glutamine from the juice of sugarbeets. L-glutamine is the most common amino acid in human blood and a key component of proteins.[47] The most abundant free amino acid in the body, glutamine is produced in the muscles and is distributed by the blood to the organs that need it.[48]
1886 Scientific development Ernst Schulze becomes the first to isolate L-arginine from lupin seedlings. L-arginine is an important amino acid in protein biosynthesis.[47]
1889 Scientific development Lysine is first isolated by German biological chemist Ferdinand Heinrich Edmund Drechsel from the protein casein in milk.[49] An essential amino acid, lysine is important for normal growth and muscle turnover and used to form carnitine, a substance found in most cells of the body.[50]
1896 Scientific development Histidine is first isolated by German physician Albrecht Kossel and Sven Gustaf Hedin.[51] A semi-essential amino acid (children should obtain it from food)[52], histidine is needed in humans for growth and tissue repair.[53] It is important for maintenance of myelin sheaths that protect nerve cells and is metabolized to the neurotransmitter histamine.[53] Histidine is abundant in meat, fish, poultry, nuts, seeds, and whole grains.[54]
1898 Scientific development The first use of the term "amino acid" in the English language dates from this year.[55]
1899 Scientific development Cystine is isolated from the horn of a cow.[56]
1890s Scientific development The United States Department of Agriculture recommends over 110 g dietary protein per day for working men.[1]
1900 Recommendation The official United States Department of Agriculture recommendations around this time are concerned only with providing sufficient protein and energy and how these could be purchased economically.[1]
1900 Scientific development German chemist Richard Willstätter first isolates proline[57] and publishes the synthesis of proline from phthalimide propylmalonic ester.[58] A nonessential amino acid[59], proline is helpful for repairing damage to the skin.[60]
1901 Scientific development German chemist Hermann Emil Fischer first isolates Valine from casein.[61] A branched-chain essential amino acid with stimulant activity, valine promotes muscle growth and tissue repair. It is a precursor in the penicillin biosynthetic pathway.[62] Valine is found mainly in protein food sources such as meats, fish, soy, and dairy.[63]
1901 Scientific development British biochemists Frederick Gowland Hopkins and Sydney William Cole discover tryptophan in the milk derivative casein.[64] An essencial amino acid, tryptophan is vital for a wide variety of metabolic functions that affect the mood, cognition, and behavior.[65]
1902 Scientific development The structure of serine is established.[66]
1902 Scientific development German chemists Emil Fischer and Fritz Weigert determine lysine's chemical structure by synthesizing it.[67]
1902 Scientific development Emil Fischer isolates hydroxyproline from hydrolyzed gelatin.[68]
1902 Recommendation W. O. Atwater recommends a dietary intake of 125 g protein per day for the average American adult, because he thinks that U.S. workmen generally work harder than Germans.W. O. Atwater, Principles of Nutrition and Nutritive Value of Food, USDA Farmers’ Bull, no. 142, 1902
1903 Scientific development German chemist Felix Ehrlich discovers isoleucine in hemoglobin.[69] Isoleucine is an amino acid present in most common proteins.[70] It is an essential amino acid[71], critical in physiological functions of the whole body, such as growth, immunity, protein metabolism, fatty acid metabolism and glucose transportation. It can improve the immune system, including immune organs, cells and reactive substances.[72] Isoleucine is abundant in meat, fish, poultry, eggs, cheese, lentils, nuts, and seeds.[73]
1905 Scientific development Synthetic isoleucine is originally reported by French chemist Louis Bouveault.[74][75]
1909 Literature American biochemist Thomas Burr Osborne publishes The Vegetable Proteins.[76]
1912 Scientific development Felix Ehrlich demonstrates that yeast metabolizes the natural amino acids essentially by splitting off carbon dioxide and replacing the amino group with a hydroxyl group. By this reaction, tryptophan gives rise to tryptophol.[77]
1914 Scientific development Citrulline is first isolated from watermelon by Japanese researchers Yotaro Koga and Ryo Odake.[78] It is a naturally occurring amino acid.[79] Two commonly seen forms of citrulline seen are citrulline malate and l-citrulline.[80] L-citrulline boosts nitric oxide production in the body. Nitric oxide helps the arteries relax and work better.[81] Citrullus vulgaris (watermelon) is the main source.[82]
1915 Scientific development Around this time, with advances in knowledge of vitamins, it begins to be understood that some of the virtues of foods come from their contribution of these accessory factors rather than from protein.[1]
1921 Scientific development American scientist John Howard Mueller first isolates methionine,[83] an essential amino acid found in many proteins, including those in foods and those found in the tissues and organs of the body.[84][85] An antioxidant, methionine may help protect the body from damage caused by ionizing radiation.[86] Methionine is abundant in turkey, beef, fish, pork, tofu, milk, cheese, nuts, beans, and whole grains like quinoa.[87]
1923 Notable comment Gregor Mendel refers to "the glorification of the albuminous substances" in earlier times, but at the time of writing "the pendulum of enthusiasm about the proteins has swung from one extreme to the other."[1]
1924 Scientific development W. C. Rose and coworkers publish a series of landmark papers on amino acid nutrition and metabolism in rats and humans that further define amino acids as nutritionally essential or nonessential, based on nitrogen balance or growth.[88]
1928 Scientific development Burger and Coen determine the structure of methionine.[89]
1930 Recommendation Fishberg recommends protein restriction for uremic patients.[90]
1935 Scientific development Jamaican pediatrician Cicely Williams introduces the term Kwashiorkor two years after publishing the disease's first formal description.[91][92] Kwashiorkor is caused by a lack of protein in the diet.[93]
1936 Scientific development Threonine becomes the last of the 20 common proteinogenic amino acids to be discovered. It is discovered by William Cumming Rose,[94] collaborating with Curtis Meyer. The amino acid is named threonine because it is found to be similar in structure to threonic acid, a four-carbon monosaccharide with molecular formula C4H8O5[95]
1939 Scientific development Walter Kempner at Duke University introduces the rice diet, low-protein diet to treat kidney disease. It consists in a daily ration of 2,000 calories of moderate amounts of boiled rice, sucrose and dextrose, and a restricted range of fruit, supplemented with vitamins. Sodium and chloride are restricted to 150mg and 200mg respectively. The rice diet shows remarkable effects on control of edema and hypertension.[96][97]
1941 Recommendation The Recommended Dietary Allowance (RDA) for protein of 0.8g per kilogram of body weight for adults is established.[98]
1948 Literature Melville Sahyun publishes Proteins and Amino Acids in Nutrition, an early book on the topic.[99]
1948 Scientific development Borst reports that a protein-free, normal calorie, low salt diet improves uremia and edema in patients with advanced renal failure.[90]
1949 Scientific development The first protein to be sequenced is insulin, by Frederick Sanger, who correctly determines its amino acid sequence, thus conclusively demonstrating that proteins consist of linear polymers of amino acids rather than branched chains, colloids, or cyclols.[100] Insulin helps regulate blood sugar levels.[101]
1950 Scientific development Protein becomes a matter of nutritional concern as a result of study of the disease, kwashiorkor in young children (usually 6 mo to 2 yr old) first in Africa and then in Jamaica, Central America and else where. This disease, with a high mortality rate, occurs after weaning onto a bulky, low protein diet, and its onset usually follows a bout with diarrhea.[1]
1950 Scientific development American biochemist William Cumming Rose identifies methionine and valine as nutritionally essential amino acids for young adults.[102][103]
1950–1975 Focus trend Around this time, the work of the Nutrition Division of Food and Agriculture Organization is based on the assumption that "deficiency of protein in the diet is the most serious and widespread problem in the world".[1]
1950–1975 Focus trend A downward trend in the successive estimates of protein requirements, particularly for children, occurs over this period.[1]
1954 Literature Adelle Davis publishes Let's Eat Right to Keep Fit, which describes the importance of combining "incomplete" proteins to make "complete" proteins, and advises that any incomplete proteins not complemented within one hour could not be used by the body.[104]
1959 Literature Anthony Albanese publishes Protein and Amino acid nutrition, which describes the state of knowledge concerning the nutrition of proteins and amino acids.[105]
1959 Scientific development Mark Hegsted of the Harvard School of Public Health warns that estimated human protein requirements are excessively reliant on non-human animal studies.[106]
1960 Recommendation William C. Rose and Robert L. Wixon from University of Illinois at Urbana-Champaign establish minimum daily requirements of essential amino acids, a discovery made in individuals without kidney disease. This discovery would contribute to the understanding of amino acid metabolism.[90]
1963 Scientific development Italian physician Carmelo Giordano applies the concept of high biological value (HBV) protein to the renal diet, in a time when only protein of animal origin is considered HBV. Giordano stresses the need for a specific quality of protein as well as quantity.[90]
1967 Notable report The United Nations Advisory Committee on the Application of Science and Technology to Development presents a report to the UN Economic and Social Council entitled 'International action to avert the impending protein crisis'. The preface states that "world food production is falling behind population growth despite all current national, bilateral and international efforts to reverse this trend". Then adds that "adequate protein is also required for the normal maintenance of body tissue and functions, and additionally for growth, maturation, pregnancy, lactation and recovery from injury and disease". The statement continues: "Today there are over 300 million children, who, for lack of sufficient protein and calories suffer grossly retarded physical growth and development, and for many of these, mental development, learning and behaviour may be impaired as well. Protein-calorie deficiencies also directly affect the health and economic productivity of adult populations".[107]
1968 Notable prediction It is predicted that, despite the promise of new technologies in the development of unconventional sources of protein food and feed, crops and livestock would continue to be the major sources of protein for human comsumption.[107]
1968 Program launch The Food and Agriculture Organization and the International Atomic Energy Agency establish an International Coordinated Research Program on the Use of Nuclear Techniques for Seed Protein Improvement, following recommendations of a panel of experts.[107]
1969 Scientific development Goldman et al. report that high protein intakes (from 6g/kg/day) in low birth weight infants are associated with a condition known as late metabolic acidosis.[108][109]
1971 Literature Frances Moore Lappé publishes Diet for a Small Planet, which explains how essential amino acids might be obtained from complementary sources in vegetarian nutrition. This book becomes a bestseller.[110]
1971 Recommendation The United Nations publishes a document, analyzing the reasons for slow progress in protein food matters and suggesting strategies to avert the protein problem confronting developing countries. Some of these include efforts to balance negative effects of the spread of higher yielding cereal varieties by expanding the 'green revolution' to pulses and oil seed crops, and strengthening the breeding programs for better protein quantity and quality in all important cereals.[107]
1972 Scientific development The Protein Advisory Group of the United Nations convenes a symposium at the Food and Agriculture Organization

headquarters in Rome bringing together experts of different fields to review nutritional and food use deficiencies, plant physiology, pathology, and production technology problems which need to be resolved in order to increase the supply of this valuable food item. Six food legumes (dry bean, pigeon pea, cow pea, chickpea, broad bean, pea) and two leguminous oil seeds (peanut, soybean) are identified as priority targets for international and national research efforts.[107]

1973 Scientific development Myosin (class I) is discovered in Acanthamoeba by Pollard and Korn.[111] Myosin is a diverse superfamily of motor proteins responsible for actin-based motility and contractility in eukaryotic cells.[112]
1975 Literature Both Vogue and American Journal of Nursing carry articles describing the principles and practice of protein combining.[113][114]
1975 Program launch The Food and Agriculture Organization and the International Atomic Energy Agency jointly organize a seminar in Sri Lanka to specify the needs for grain legume improvement in South East Asia and to consider the contribution that could be expected from widening genetic variability through mutation induction. It is recognized that many of the currently cultivated legume species still possess a number of 'wild type' characteristics that were beneficial during past natural evolution, but hinder the upgrading of grain production under more intensive farming conditions. South East Asia is an area where many vegetarians rely upon pulses as their main protein source.[107]
1978 Literature The American Chemical Society Division of Agricultural and Foods Chemistry publishes Nutritional Improvement of Food and Feed Proteins.[115]
1979 Scientific development Isner publishes a report of 17 deaths associated with low-quality liquid protein VLCD, due to heart-related causes.[116]
1982 Scientific development Rennie et al. (and later Bennet et al. in 1990[117]) demonstrate that a mixed macronutrient meal is capable of increasing rates of muscle protein synthesis above rates of muscle protein breakdown and that the amino acids contained within the meal are primarily responsible for this increase.[118]
1989 Literature C.A. Barth and E. Schlimme publish Milk Proteins: Nutritional, Clinical, Functional and Technological Aspects, which reviews the state of knowledge and progress of research on food proteins, and in particular, milk proteins.[119]
1990 Literature Raul A. Wapnir publishes Protein Nutrition and Mineral Absorption, which presents information regarding the mechanisms of protein absorption under normal and pathologic conditions, in addition to reviewing changes that occur at various stages of life.[120]
1993 Policy The Protein Digestibility Corrected Amino Acid Score (PDCAAS) is adopted by the US Food and Drug Administration (FDA) and the Food and Agricultural Organization of the United Nations/World Health Organization (FAO/WHO) as "the preferred 'best'" method to determine protein quality. These organizations suggest that other methods for evaluating the quality of protein are inferior.[121]
1994 Scientific development Vernon Young and Peter Pellett publish their paper that becomes the definitive contemporary guide to protein metabolism in humans. It also confirms that complementing proteins at meals is totally unnecessary. Thus, people who avoid consuming animal protein do not need to be at all concerned about amino acid imbalances from the plant proteins that make up their usual diets.[122]
1994 Literature Zdzisław Sikorski, Bonnie Sun Pan, and Fereidoon Shahidi publish Seafood Proteins, a presentation of the state of knowledge on seafood nitrogenous compounds.[123]
1994 Scientific development The Arp2/3 complex (Actin Related Protein 2/3 complex) is named after being identified by affinity chromatography from Acanthamoeba castellanii.[124] The Arp2/3 complex is an essential component of the actin cytoskeleton in eukaryotic cells.[125]
1995 Literature Clarence B. Ammerman, David P. Baker, and Austin J. Lewis publish Bioavailability of Nutrients for Animals: Amino Acids, Minerals, Vitamins, which attempts to provide information necessary to formulate diets with appropriate amounts of amino acids, minerals, and vitamins.[126]
1995 Scientific development Biolo et al. report that insulin therapy improves protein metabolism.[127]
1996 Scientific development Mahe et al. report that soy protein contains a greater proportion of nonessential amino acids than whey protein.[128]
2000 Scientific development The term proteopathy is first proposed by Lary Walker and Harry LeVine.[129] It refers to a disease characterized by the production of aberrant conformers of certain proteins that are misfolded and aggregate in a crystallization-like seeding mechanism—changes that lead to a disturbance of their cellular functions and disease.[130]
2000 Scientific development Brunton et al. show that the gut has a major effect on amino-acid metabolism.[108]
2000 Scientific development Bos et al. conclude that milk proteins are of excellent nutritional value as they have a high metabolic utilization by the organism.[131]
2002 Recommendation The U.S. Institute of Medicine sets a Recommended Dietary Allowance (RDA) of 5 mg/kg body weight/day of Tryptophan for adults 19 years and over.[132]
2002 Notable comment American physician Dr. John McDougall writes a correction to the American Heart Association for a 2001 publication that questions the completeness of plant proteins, and further asserts that "it is impossible to design an amino acid–deficient diet based on the amounts of unprocessed starches and vegetables sufficient to meet the calorie needs of humans."[133]
2004 Literature Rickey Y. Yada publshes Proteins in Food Processing, which reviews how proteins may be used to enhance the nutritional, textural and other qualities of food products.[134]
2005 Notable comment Dr. Joel Fuhrman writes:
...plant foods have plenty of protein and you do not have to be a nutritional scientist or dietitian to figure out what to eat and you don’t need to mix and match foods to achieve protein completeness. Any combination of natural foods will supply you with adequate protein, including all eight essential amino acids as well as unessential amino acids.[135]
2005 Scientific development Bos et al. show that wheat proteins are the more gluconeogenic because of their high deamination rate and their high glutamine content.[136] Gluconeogenesis is the metabolic process by which glucose is formed from noncarbohydrate sources, such as lactate, amino acids, and glycerol.[137]
2006 Notable comment Dr. T. Colin Campbell writes:
We now know that through enormously complex metabolic systems, the human body can derive all the essential amino acids from the natural variety of plant proteins that we encounter every day. It doesn’t require eating higher quantities of plant protein or meticulously planning every meal.[138]
2007 Recommendation Isotope studies and reappraisal of nitrogen balance literature using nonlinear regression suggest that the WHO 2007 (Report of a Joint WHO/FAO/UNU Expert Consultation, 2007) estimates of adult protein requirements are too low, by a factor of around 30%.[108]
2007 Recommendation The World Health Organization 2007 Technical Report on protein and amino acid requirements in human nutrition states that the best estimate for a population average requirement is 105 mg nitrogen/kg body weight per day, or 0.66 g protein/kg body weight per day.[139]
2007 Scientific development Bauchart et al. report having identified in the stomach effluent a large number of peptides deriving from actin and myosin (the main muscle proteins) after meat or fish consumption.[140]
2008 Scientific development Pikachurin is first discovered in Japan by Shigeru Sato et al. and named after Pikachu, a species of the Pokémon franchise.[141] An extracellular matrix-like retinal protein, its name is inspired by Pikachu's "lightning-fast moves and shocking electric effects".[142]
2009 Notable comment The American Dietetic Association writes:
Plant protein can meet protein requirements when a variety of plant foods is consumed and energy needs are met. Research indicates that an assortment of plant foods eaten over the course of a day can provide all essential amino acids and ensure adequate nitrogen retention and use in healthy adults, thus, complementary proteins do not need to be consumed at the same meal.[143]
2010 Scientific development A study from the University of Copenhagen concludes that protein requirements should be based on criteria related to long-term health and well-being, rather than on nitrogen balance alone.[144][139]
2011 Scientific development A review concludes that a "long-term effect of high-protein diets is neither consistent nor conclusive."[145]
2011 Literature G. O. Phillips and P. A. Williams publish their Handbook of Food Proteins, which provides an overview of the characteristics, functionalities and applications of different proteins of importance to the food industry.[146]
2011 Scientific development Rubinsztein et al. report that autophagy eliminates protein aggregates that are toxic to the cell, thus mediating cytoprotection.[147]
2012 Scientific development Study shows that exercise regulates protein synthesis.[148]
2013 Scientific development Bollwein et al. report that protein intake may be more evenly distributed throughout the day in the frail elderly population than in healthy adults.[149]
2014 Scientific development A review notes that high-protein diets from animal sources should be handled with caution.[150]
2014 Scientific development Researchers report that resistance in older people to postprandial anabolic stimulation by dietary protein can be overcome by supplying daily protein in the form of protein-rich meals.[151][152]
2015 Recommendation Layman et al. recommend daily allowance for dietary protein intake by an adult person at 0.8 g/kg per day, irrespective of overall energy intake.[153]
2015–2020 Recommendation The 2015–2020 Dietary Guidelines for Americans (DGA) recommends that men and teenage boys increase their consumption of fruits, vegetables and other under-consumed foods, and that a means of accomplishing this would be to reduce overall intake of protein foods.[154]
2016 Notable comment The American Heart Association states:
You don’t need to eat foods from animals to have enough protein in your diet. Plant proteins alone can provide enough of the essential and non-essential amino acids, as long as sources of dietary protein are varied and caloric intake is high enough to meet energy needs. Whole grains, legumes, vegetables, seeds and nuts all contain both essential and non-essential amino acids. You don’t need to consciously combine these foods (“complementary proteins”) within a given meal.[155]
2017 Scientific development A review indicates that a high-protein diet may contribute to life-long risk of kidney damage, including chronic kidney disease.[156]
2020 Scientific development A review finds that a high-protein diet does not significantly improve blood pressure and glycemic control in people with diabetes.[157]

Tabular and visual data

The table below shows daily protein intake (g) by age, education, work, status, income and geographical region, in Chinese women from 1991 to 2015.[158]

1991 Mean 1991 SE 1993 Mean 1993 SE 1997 Mean 1997 SE 2000 Mean 2000 SE 2004 Mean 2004 SE 2006 Mean 2006 SE 2009 Mean 2009 SE 2011 Mean 2011 SE 2015 Mean 2015 SE
Age group (year):
18-49 70.3 0.4 69.9 0.4 67.9 0.4 65.7 0.4 65.0 0.4 65.2 0.4 63.9 0.4 61.0 0.4 57.7 0.4
50-64 67.7 0.7 66.3 0.9 63.6 0.8 63.9 0.7 64.8 0.7 64.6 0.6 62.4 0.6 59.0 0.5 56.2 0.4
Education level:
Primary/ illiterate 69.6 0.5 68.9 0.5 66.0 0.5 63.7 0.5 64.1 0.5 64.5 0.5 62.7 0.5 58.0 0.5 57.0 0.5
Middle school 69.9 0.6 69.8 0.7 67.9 0.6 66.3 0.6 64.2 0.6 65.6 0.6 63.9 0.5 60.8 0.5 58.2 0.6
High/above 70.4 0.8 69.9 0.9 68.7 0.8 67.0 0.7 67.3 0.7 64.9 0.7 63.8 0.7 62.2 0.6 56.3 0.4
Income:
Low 68.9 0.6 68.7 0.6 65.7 0.6 64.0 0.6 62.7 0.6 64.9 0.6 63.0 0.5 59.8 0.5 55.7 0.5
Medium 70.0 0.6 69.1 0.6 67.7 0.6 64.9 0.6 66.2 0.6 65.2 0.6 63.1 0.6 59.4 0.5 55.9 0.5
High 70.5 0.6 70.3 0.6 67.7 0.6 67.0 0.6 65.9 0.6 65.0 0.6 64.1 0.5 61.5 0.5 59.2 0.5
Region:
Rural 69.6 0.5 70.4 0.6 69.7 0.6 67.8 0.6 66.8 0.6 66.6 0.7 64.0 0.6 61.3 0.5 55.4 0.3
Urban 69.9 0.4 68.8 0.4 65.8 0.4 64.1 0.4 64.1 0.4 64.3 0.4 63.2 0.4 59.7 0.3 59.5 0.4
BMI category:
Underweight 64.9 1.1 67.3 1.2 63.8 1.2 63.5 1.4 63.9 1.5 62.5 1.4 59.2 1.1 59.0 1.2 56.3 1.0
Normal 69.9 0.4 68.9 0.4 66.9 0.4 65.5 0.4 64.6 0.5 64.7 0.4 63.6 0.4 60.6 0.4 57.0 0.4
Overweight/ obesity 71.5 0.7 71.3 0.7 68.3 0.7 65.2 0.6 65.8 0.6 66.1 0.6 63.9 0.5 60.0 0.5 57.2 0.4
Total 69.8 0.3 69.3 0.4 67.1 0.3 65.3 0.3 64.9 0.4 65.0 0.3 63.4 0.3 60.3 0.3 57.0 0.3

The table below shows changing views of the role of amino acids in human nutrition.[159]

1954 Indispensable 1994 Indispensable 1994 Conditionally indispensable 1954 Dispensable 1994 Dispensable
Valine Valine Glycine Glycine Glutamic acid
Isoleucine Isoleucine Cystine Cystine Alanine
Leucine Leucine Glutamine Glutamic acid Serine
Lysine Lysine Tyrosine Tyrosine Aspartic acid
Methionine Methionine Proline Proline Asparagine
Phenylalanine Phenylalanine Arginine Arginine
Threonine Threonine Taurine Alanine
Tryptophan Tryptophan Serine
Histidine Aspartic acid
Histidine
Hydroxyproline
Citrulline


The table below shows estimates made at different times of the protein and energy requirements of children at 1 year of age.[1]

Year Protein Energy Protein energy Source
g/kg body wt kcal/kg body wt  % of total energy
1948 3.3 100 13.2 USA
1957 2.0 100 8.0 FAO
1964 2.5 100 10.0 USA
1965 1.1 100 4.4 FAO/WHO
1968 1.8 100 7.2 USA
1969 1.3 110 4.7 UK
1973 1.27 105 4.8 FAO/WHO
1974 1.35 100 5.4 USA

Google Schoolar

The following table summarizes per-year mentions on Google Scholar as of October 3, 2021.

Year "protein"
1900 405
1910 925
1920 1,910
1930 3,360
1940 5,070
1950 9,590
1960 21,100
1970 64,500
1980 170,000
1990 472,000
2000 1,110,000
2010 1,600,000
2020 274,000
Protein gsch.png

The table below shows dietary requirements of protein (g per kg body weight per day).[160]

Group Age (Years) IOM 2005 FAO/ WHO/ UNU 1985 FAO/ WHO/ UNU 2007
Infants 0.3-0.5 1.52 1.75 1.31
0.75-1.0 1.50 1.57 1.14
Children 1-3 1.10 1.18 1.02
4-8 0.95 1.05 0.92
Adolescents 9-13 0.95 0.99 0.90
14-18 (boys) 0.85 0.97 0.87
14-18 (girl) 0.85 0.94 0.85
Adults >19 0.80 0.75 0.83


The table below shows dietary requirements of essential amino acids by healthy human adults.[160]

EAA Estimates from N balance experiments Men Estimates from N balance experiments Women MIT values (tracer studies) (2000) IOM (2005) FAO/ WHO UNU (2007)
His - - - 14 10
Ile 10 9.17 23 19 20
Leu 15.7 12.1 40 42 39
Lys 11.4 9.07 30 38 30
Met 2.36 3.23 - - -
Met+Cys 15.7 11.7 13 19 15
Phe 4.29 4.30 - - -
Phe+Tyr 15.7 - 39 33 25
Thr 7.14 6.25 15 20 15
Trp 3.57 2.80 6 5 4
Val 11.4 10.4 20 24 26
Total 90.6 65.8 186 214 184


Google Trends

The comparative chart below shows Google Trends data for Protein (Nutrient) and Protein (Topic) from January 2004 to October 2021, when the screenshot was taken. Interest is also ranked by country and displayed on world map.[161]

Protein gt.png

Google Ngram Viewer

The comparative chart below shows Google Ngram Viewer data for Protein, amino acid and calorie from 1800 to 2019.[162]

Protein ngram.png

Wikipedia Views

The chart below shows pageviews of the English Wikipedia article Protein, from July 2015 to September 2021.[163]

Protein wv.png


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Timeline update strategy

See also

External links

References

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