Vitamin discoveries Vitamers Vitamin X Commentary

Elmer McCollum, Marguerite Davis, Lafayette Mendel, Thomas Burr Osborne, Christiaan Eijkman, Edward Mellanby, Adolf Windaus, Herbert McLean Evans, Katharine Bishop, Carl Dam, George Whipple, George Richards Minot, William Murphy, Albert Szent-Györgyi food science

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.