1897 | Dutch physician Christiaan Eijkman (1858–1930) cures beriberi in chickens with diet of whole rice. |
1906–07 | British biochemist Sir Frederick Hopkins demonstrates existence of accessory dietary elements essential for growth. |
1912 | Polish-born US biochemist Casimir Funk (1884–1967) extracts antiberiberi factor (an amine) from rice husks and coins the term ‘vitamine’ (vital amine; later changed to ‘vitamin’). |
1913 | US biochemist Elmer McCollum (1879–1967) discovers and names vitamin A (retinol) and names antiberiberi factor vitamin B. |
1920 | McCollum names antirachitic factor vitamin D. |
1922 | US embryologist Herbert Evans (1882–1971) discovers vitamin E (tocopherol). |
1926 | German chemist Adolf Windaus (1876–1959) discovers that ergosterol is converted to vitamin D in the presence of sunlight. |
1931 | German chemist Paul Karrer (1889–1971) determines the structure of (and synthesizes) vitamin A. |
1932 | Hungarian-born US biochemist Albert Szent-Györgyi (1893–1986) and US biochemist Charles King (1896–1986) independently isolate vitamin C (ascorbic acid). |
1933 | Polish-born Swiss chemist Tadeus Reichstein (1897–1996) and British chemist Walter Haworth (1883–1950) independently synthesize vitamin C. |
| US chemist Roger Williams (1893–1988) discovers the B vitamin pantothenic acid. |
1934 | Danish biochemist Carl Dam (1895–1976) discovers vitamin K. |
1935 | Karrer and Austrian-born German chemist Richard Kuhn (1900–67) independently synthesize vitamin B2 (riboflavin). |
1937 | US chemist Robert Williams (1886–1965) synthesizes vitamin B1 (thamine). |
1938 | Karrer synthesizes vitamin E. |
| Kuhn isolates and synthesizes vitamin B6 (pyridoxine). |
1939 | Dam and Karrer isolate vitamin K. |
1940 | Szent-Györgyi and US biochemist Vincent Du Vigneaud (1901–78) discover ‘vitamin H’ (the B vitamin biotin). |
| Roger Williams determines the structure of pantothenic acid. |
| US biochemist Edward Doisey synthesizes vitamin K. |
1948 | US biochemist Karl Folkers (1906–97) isolates vitamin B12 (cyanocobalamin). |
1956 | British chemist Dorothy Hodgkin (1910–94) determines the structure of vitamin B12. |
1971 | US chemist Robert Woodward (1917–79) and Swiss chemist Albert Eschenmoser (1925– ) synthesize vitamin B12. |