Editing Thiamine (section)

==History==
{{See|Vitamin#History}}
Thiamine was the first of the water-soluble vitamins to be isolated.<ref name=Suzuki/> The earliest observations in humans and in chickens had shown that diets of primarily polished white rice caused beriberi, but did not attribute it to the absence of a previously unknown essential nutrient.<ref name="McCollum"/><ref name=Eijkman1897/>

In 1884, [[Takaki Kanehiro]], a surgeon general in the [[Imperial Japanese Navy]], rejected the previous [[Germ theory of disease|germ theory]] for beriberi and suggested instead that the disease was due to insufficiencies in the diet.<ref name="McCollum">{{cite book | vauthors = McCollum EV | title = A History of Nutrition | location = Cambridge, Massachusetts | publisher = Riverside Press, [[Houghton Mifflin]] |date = 1957 }}</ref> Switching diets on a navy ship, he discovered that replacing a diet of white rice only with one also containing barley, meat, milk, bread, and vegetables, nearly eliminated beriberi on a nine-month sea voyage. However, Takaki had added many foods to the successful diet and he incorrectly attributed the benefit to increased protein intake, as vitamins were unknown at the time. The Navy was not convinced of the need for such an expensive program of dietary improvement, and many men continued to die of beriberi, even during the [[Russo-Japanese war]] of 1904–5. Not until 1905, after the anti-beriberi factor had been discovered in [[Bran#Rice bran|rice bran]] (removed by [[rice polisher|polishing into white rice]]) and in barley bran, was Takaki's experiment rewarded. He was made a baron in the Japanese peerage system, after which he was affectionately called "Barley Baron".<ref name="McCollum"/>

The specific connection to grain was made in 1897 by [[Christiaan Eijkman]], a military doctor in the [[Dutch East Indies]], who discovered that fowl fed on a diet of cooked, polished rice developed paralysis that could be reversed by discontinuing rice polishing.<ref name=Eijkman1897>{{cite journal |vauthors = Eijkman C |year = 1897 |title = Eine Beriberiähnliche Krankheit der Hühner |trans-title = A disease of chickens which is similar to beriberi |url = https://zenodo.org/record/1572089 |journal = Archiv für Pathologische Anatomie und Physiologie und für Klinische Medicin |volume = 148 |issue = 3 |pages = 523–532 |doi = 10.1007/BF01937576 |s2cid = 38445999 |access-date = 4 July 2019 |archive-date = 9 August 2020 |archive-url = https://web.archive.org/web/20200809120608/https://zenodo.org/record/1572089 |url-status = live }}</ref> He attributed beriberi to the high levels of [[starch]] in rice being toxic. He believed that the toxicity was countered in a compound present in the rice polishings.<ref name="Nobel">{{cite web|title=The Nobel Prize and the Discovery of Vitamins|url=https://www.nobelprize.org/nobel_prizes/themes/medicine/carpenter/|website=nobelprize.org|access-date=1 May 2018|archive-date=16 January 2018|archive-url=https://web.archive.org/web/20180116004953/https://www.nobelprize.org/nobel_prizes/themes/medicine/carpenter/|url-status=live}}</ref> An associate, [[Gerrit Grijns]], correctly interpreted the connection between excessive consumption of polished rice and beriberi in 1901: He concluded that rice contains an essential nutrient in the outer layers of the grain that is removed by polishing.<ref>{{cite journal |vauthors = Grijns G |year = 1901 |title = Over polyneuritis gallinarum |trans-title = On polyneuritis gallinarum |url = https://babel.hathitrust.org/cgi/pt?id=uc1.b3748913&view=1up&seq=29 |journal = Geneeskundig Tijdschrift voor Nederlandsch-Indië (Medical Journal for the Dutch East Indies) |volume = 41 |issue = 1 |pages = 3–11 |access-date = 5 February 2020 |archive-date = 29 August 2021 |archive-url = https://web.archive.org/web/20210829084152/https://babel.hathitrust.org/cgi/pt?id=uc1.b3748913&view=1up&seq=29 |url-status = live }}</ref> Eijkman was eventually awarded the [[Nobel Prize in Physiology and Medicine]] in 1929, because his observations led to the discovery of vitamins.

In 1910, a Japanese agricultural chemist of [[University of Tokyo|Tokyo Imperial University]], [[Umetaro Suzuki]], isolated a water-soluble thiamine compound from rice bran, which he named ''aberic acid''. (He later renamed it ''Orizanin''.) He described the compound as not only an anti-beriberi factor, but also as being essential to human nutrition; however, this finding failed to gain publicity outside of Japan, because a claim that the compound was a new finding was omitted in translation of his publication from Japanese to German.<ref name=Suzuki>{{cite journal | title = Active constituent of rice grits preventing bird polyneuritis | journal = Tokyo Kagaku Kaishi | year = 1911 | vauthors = Suzuki U, Shimamura T | volume = 32 | pages = 4–7, 144–6, 335–58 | doi = 10.1246/nikkashi1880.32.4 | doi-access = free | url = https://www.jstage.jst.go.jp/browse/nikkashi1880/32/1/_contents | access-date = 2 May 2018 | archive-date = 21 June 2020 | archive-url = https://web.archive.org/web/20200621103704/https://www.jstage.jst.go.jp/browse/nikkashi1880/32/1/_contents | url-status = live }}</ref> In 1911 a Polish biochemist [[Casimir Funk]] isolated the [[Wikt:antineuritic|antineuritic]] substance from rice bran (the modern thiamine) that he called a "vitamine" (on account of its containing an amino group).<ref>{{cite journal | vauthors = Funk C | title = On the chemical nature of the substance which cures polyneuritis in birds induced by a diet of polished rice | journal = The Journal of Physiology | volume = 43 | issue = 5 | pages = 395–400 | date = December 1911 | pmid = 16993097 | pmc = 1512869 | doi = 10.1113/jphysiol.1911.sp001481 }}</ref><ref>{{cite journal | vauthors = Funk C | title = The etiology of the deficiency diseases. Beri-beri, polyneuritis in birds, epidemic dropsy, scurvy, experimental scurvy in animals, infantile scurvy, ship beri-beri, pellagra | journal = Journal of State Medicine | date = 1912 | volume = 20 | pages = 341–68 | url = https://babel.hathitrust.org/cgi/pt?id=mdp.39015069802166&view=1up&seq=351 | access-date = 5 February 2020 | archive-date = 4 July 2020 | archive-url = https://web.archive.org/web/20200704183954/https://babel.hathitrust.org/cgi/pt?id=mdp.39015069802166&view=1up&seq=351 | url-status = live }} The word "vitamine" is coined on p. 342: "It is now known that all these diseases, with the exception of pellagra, can be prevented and cured by the addition of certain preventative substances; the deficient substances, which are of the nature of organic bases, we will call "vitamines"; and we will speak of a beri-beri or scurvy vitamine, which means a substance preventing the special disease."</ref> However, Funk did not completely characterize its chemical structure. Dutch chemists, [[Barend Coenraad Petrus Jansen]] and his closest collaborator Willem Frederik Donath, went on to isolate and crystallize the active agent in 1926,<ref>{{cite journal | vauthors = Jansen BC, Donath WF | year = 1926 | title = On the isolation of antiberiberi vitamin | journal = Proc. Kon. Ned. Akad. Wet. | volume = 29 | pages = 1390–400 }}</ref> whose structure was determined by [[Robert Runnels Williams]], in 1934. Thiamine was named by the Williams team as a [[portmanteau]] of "thio" (meaning sulfur-containing) and "vitamin". The term "vitamin" coming indirectly, by way of Funk, from the amine group of thiamine itself (although by this time, vitamins were known to not always be amines, for example, [[vitamin C]]). Thiamine was also synthesized by the Williams group in 1936.<ref>{{cite journal | doi = 10.1021/ja01299a505 | title = Synthesis of Vitamin B<sub>1</sub> | year = 1936 | vauthors = Williams RR, Cline JK | journal = Journal of the American Chemical Society | volume = 58 | issue = 8 |pages = 1504–5 | bibcode = 1936JAChS..58.1504W }}</ref>

Sir [[Rudolph Peters]], in [[Oxford University|Oxford]], used pigeons to understand how thiamine deficiency results in the pathological-physiological symptoms of beriberi. Pigeons fed exclusively on polished rice developed [[opisthotonos]], a condition characterized by head retraction. If not treated, the animals died after a few days. Administration of thiamine after opisthotonos was observed led to a complete cure within 30 minutes. As no morphological modifications were seen in the brain of the pigeons before and after treatment with thiamine, Peters introduced the concept of a biochemical-induced injury.<ref>{{cite journal | vauthors = Peters RA | title = The biochemical lesion in vitamin B<sub>1</sub> deficiency. Application of modern biochemical analysis in its diagnosis |journal = Lancet |year = 1936 | volume = 230 | issue = 5882 |pages = 1161–4 |doi = 10.1016/S0140-6736(01)28025-8 }}</ref> In 1937, Lohmann and Schuster showed that the diphosphorylated thiamine derivative, TPP, was a cofactor required for the oxidative decarboxylation of pyruvate.<ref>{{cite journal | vauthors = Lohmann K, Schuster P |year = 1937 |title = Untersuchungen über die Cocarboxylase |journal = Biochem. Z. |volume = 294 |pages = 188–214 }}</ref>

<gallery caption="Some contributors to the discovery of thiamine" mode="nolines">
File:Takaki Kanehiro.jpg|[[Takaki Kanehiro]]
File:Eijkman.jpg|[[Christiaan Eijkman]]
File:Portrait_of_Gerrit_Grijns_Wellcome_M0010254.jpg|[[Gerrit Grijns]]
File:Umetarosuzuki-pre1943.jpg|[[Umetaro Suzuki]]
File:Casimir_Funk_01.jpg|[[Casimir Funk]]
File:Rudolph Albert Peters.jpg|[[Rudolph Peters]]
</gallery>