Contrary to the dogma that all fats had similar nutritional value, in 1913, Elmer McCollum and his associate Marguerite Davis at Wisconsin showed butter and egg yolk were not equivalent to lard and olive oil in supporting the growth and survival of rats. The growth-supporting ‘accessory factor’ became known as ‘fat-soluble A’ in 1918 and then ‘vitamin A’ in 1920.
“Fat-soluble A” was first believed to be a single vitamin capable of curing xerophthalmia and rickets. Cod-liver oil was first used as a therapeutic agent in the 1770s. McCollum showed that cod-liver oil aerated at the temperature of boiling water for 12 to 20 hr retained its antirachitic activity in rats, but was ineffective against xerophthalmia. In addition, these properties were unequally distributed in certain foods. Apparently, two separate factors were involved. The factor effective against rickets later was named vitamin D.
The discovery of vitamin A by McCollum and Davis in 1913 ushered in the era of accessory food substances culminating in the achievement of that goal. It included the discovery of vitamin D and its production in skin caused by ultraviolet light. This was followed by a description of its actions at the physiological level that resulted in a healthy skeleton and beyond.
In 1915 McCollum and Davis had found that when water oralcohol extractions of wheat germ or rice polishing were added, polished rice was greatly improved in nutritional quality. These experiments constituted the basis for their discovery that the anti-beriberi factor, necessary to relieve polyneuritis in pigeons, was necessary for rats and that there were apparently only two unidentified nutrients necessary for such animals.
They proposed the term fat-soluble A and water-soluble B, respectively, to designate the two unidentified nutrients. The isolation of B1was achieved in 1926 by Dutch scientists in Java using small “rice birds” fed on washed white rice supplemented with cod liver oil for their assays.
Elmer
McCollum - Discovering Vitamin A, Vitamin B and Vitamin D
