Nutrition and Infection

The idea that a normal state of nutrition confers resistance to infection has long been held. Following the discovery of the accessory food elements, since 1900 an enormous amount of study has been devoted both to the defining of the various nutritional deficiencies and to a search for those food factors which might promote resistance. In this work, experiments with animals have been indispensable and have led to the solution of some of the clinical problems. It has been found that (1) outspoken deficiencies may lower resistance to infection; (2) increased feeding of such food elements as vitamin A to the normal animal may not increase resistance; (3) the results obtained with one species do not necessarily apply to another species; (4) very few studies have been made in animals receiving a diet only partially deficient, yet partial deficiency in man is far more frequent than total deficiency; (5) multiple