McCollum, Elmer Verner (1879-1967)

US biochemist and nutritionist who originated the letter system of naming vitamins. He also researched into the role of minerals in the diet. His choice of the albino rat as a laboratory animal was to make it one of the most used animals for research. McCollum was born in Fort Scott, Kansas, and studied at Kansas and Yale universities. He worked at the University of Wisconsin 1907-17. From 1917 he was professor at the School of Hygiene and Public Health at Johns Hopkins University. McCollum discovered in the early 1910s that growth retardation results from a diet deficient in certain fats and that such deficiencies can be compensated for by providing a specific extract from either butter or eggs. He called this essential component 'fat-soluble A', because it dissolves in lipids. He then showed that there is another essential dietary component, which he called 'water-soluble B'. Later he found that they are not single compounds but complexes. At Johns Hopkins, McCollum collaborated in the discovery of vitamin D.