Vitamin E History
The existence of a dietary factor essential for reproduction in the rat was recognized in the early 1920 by Evans; Sure named it vitamin E, or antisterility factor. In rats, on which much of the experimental work was done, the males and the females are affected differently. Vitamin E deficiency leads to destruction of germ cells in the testes of the male and thus to permanent sterility. In a vitamin E deficient female mated with a normal male, ovulation and implantation of the ovum may take place normally, but about halfway through the gestation period resorption of the developing fetus occurs, and no young are born. With less severe vitamin E deficiency, which may permi t the birth of a weakling litter, the chances of survival are poor because this same deficiency seems to interfere \vith lactation or, later, with growth of the young.
Vitamin E has turned out to be perhaps the most elusive of the nutritional factors discovered so far. In experimental animals a large number of different deficiency symptoms and distinct deficiency diseases were demonstrated, depending on the species. Furthermore, it was later discovered that some of these conditions could be either totally or partially prevented by factors other than vitamin E, for example, selenium, various compounds with antioxidant activity, and sulfur-amino acids. It was also discovered that high intake of polyunsaturated fatty acids increased the severity of some but not all of these syndromes. It now appears that although the manifestations in different species vary, the same body systems are involved the reproductive system, the musculature, the nervous, and the vascular systems.
Even more perplexing has been the fact that no clinical evidence of vitamin E deficiency could be produced in humans. Evidence has failed to indicate that vitamin E is a significant factor in reproduction or muscular dystrophy, the first two conditions that were extensively studied in connection with the effects of vitamin E in humans. Even though the role of vitamin E in human nutrition is still not well defined, there is no question that it is an essential nutrient for human health.
