1913-1930

Vitamin discoveries

• After Frederick Gowland Hopkins asserted
• that food contained hidden essential nutrients,
• work began to discover what these “accessory factors” were.
• Vitamins A and B₁, 1913
• Separately, Elmer McCollum with Marguerite Davis at Madison
• and Lafayette Mendel with Thomas Burr Osborne at Yale
• identified a fat-soluable substance found in butter and cod liver oil
• that was essential for growth and vision.
• McCollum called it factor A.
• The two teams also identified
• a water-soluable substance found in milk
• that was later identified as thiamine, vitamin B₁.
• In 1915, McCollum realized this was the substance
• identified by Christiaan Eijkman
• that was found in rice hulls, and prevented beriberi.
• McCollum and Davis started the first colony of rats in the U.S.
• for studying the effects of dietary nutrients.
• Supportive of the milk industry in Wisconsin,
• McCollum advocated lacto vegetarianism.
• Vitamin D, 1922
• Before 1920, Edward Mellanby had found
• that cod liver oil cured dogs of rickets,
• and reasoned that vitamin A
• or something close to it was the reason.
• Elmer McCollum destroyed the vitamin A in cod liver oil
• and found that this oil cured dogs of rickets.
• McCollum called the essential part of the oil vitamin D.
• In 1925, Adolf Windaus showed that cholesterol on the skin
• is converted by sunlight to vitamin D₃,
• otherwise known as cholecalciferol.
• Vitamin E, 1922
• Herbert McLean Evans and Katharine Bishop,
• in feeding experiments with rats,
• discovered vitamin E, a fat-soluble antioxidant,
• which is essential for reproduction.
• Later work showed it to be a group of compounds
• including tocopherols and tocotrienols.
• Vitamin B₁₂, 1920-1926
• George Whipple discovered that feeding dogs liver
• helped them recover from anemia the quickest.
• George Richards Minot and William Murphy
• found that for dogs iron from the liver was sufficient
• but that for humans something else was needed
• and it could be found in the juices from the liver.
• Eventually, the water-soluble essence
• was extracted from bacterial broths
• and called vitamin B₁₂.
• Vitamin K, 1929
• Carl Dam found that chickens fed a diet without fat
• suffered from hemorrhages and bleeding,
• and that normal blood coagulation
• was not restored by reintroducing cholesterol.
• Carl Dam called the essential oil Koagulationsvitamin,
• so it’s called vitamin K.
• Vitamin C, 1930
• Albert Szent-Györgyi got his PhD in 1927
• for isolating “hexuronic acid” from adrenal glands.
• By 1930, he and his research fellow Joseph Svirbely
• found that this acid was the previously unidentified
• factor in limes that cured scurvy.

Vitamers

• Vitamin A has several forms,
• reinol, retinal, retinoic acid,
• alpha-carotene, beta-carotene, gamma-carotene,
• and xanthophyll beta-cryptoxanthin,
• all of which contain a retinyl group
• and are converted to retinol in the body.
• Vitamin B has eight vitamers
• numbered 1 to 12, skipping 4, 8, 10, and 11,
• which I think had been proposed
• but failed to pass the test, leaving
• thiamine (B₁),
• riboflavin (B₂),
• niacin (B₃),
• pantothenic acid (B₅),
• pyridoxine (B₆),
• biotin (B₇),
• folic acid (B₉),
• and cyanocobalamin, hydroxocobalamin,
• methylcobalamin, and adenosylcobalamin
• (all B₁₂ vitamers)
• Vitamin C is ascorbic acid,
• but salts of ascorbic acid are also included,
• dehydroascorbic acid, calcium ascorbate,
• sodium ascorbate, and more.
• Vitamin D includes calcitriol (D₁),
• ergocalciferol (D₂), cholecalciferol (D₃).
• Vitamin E is various tocopherols and tocotrienols.
• Vitamin K includes phylloquinone (K₁),
• menaquinones (K₂), menadiones (K₃).

Vitamin X

• At our holiday party, an inspired coworker
• used to say, “I need more vitamin S,” S for sugar.
• We could all use more vitamin H₁, for happiness,
• vitamin P for peace, and vitamin L for love.
• I’m wondering whether the generosity vitamin G
• will turn out to be water-soluable or fat-soluable.
• Will food or sunlight supply our daily requirements
• of vitamin J for joy, or F for good fortune?
• Will caffeine turn out to be vitamin C₂?
• Other candidates could be remedies for a lack of compassion,
• or kindness, or patience, or a cure for cancer.
• Will something simple prove to compensate for deficiencies
• of I for imagination? R for reason? vitamin P for poetry?
• One may have H₂ for hope and still look for that elusive vitamin X.