Oral contraceptive agents alter the metabolism of some nutrients, which could affect nutritional requirements. The effects of oral contraceptives on pyridoxine, folacin, thiamin, riboflavin, vitamin A, ascorbic acid, zinc, and copper as determined by studies done in the last five years are reviewed. Evidence for actual nutritional deficiencies due to the use of oral contraceptives is still insufficient, and more research is needed. Supplements are advised only for those women in whom other factors, such as disease, impair nutritional adequacy.
PIP: Metabolic changes caused by oral contraceptives (OCs) in terms of the vitamins pyridoxine, folacin, thiamin, riboflavin, ascorbic acid, and A and the minerals zinc and copper are discussed. Pyroxidine in the form of coenzyme pyridoxal phosphate is involved in conversion of tryptophan to niacin, and tryptophan load tests have shown that certain metabolites of B6 have increased secretion when OCs are used. Folic acid deficiency has been found in some OC users. As with pyroxidine and folacin, OC users may require supplementation of thiamin as well. When riboflavin deficiency is preexistent, OCs exacerbate the condition (this effect may be race-dependent). Vitamin A, in contrast to the B vitamins, increases in the plasma of women taking OCs, perhaps due to greater mobilization of the vitamin by the liver. OC users generally show significantly lower leukocyte and platelet levels of ascorbic acid, and supplementation may be necessary. Zinc levels generally decrease, whereas copper levels in serum significantly increase in association with OC use. At present, supplements of vitamins and minerals are recommended only for high-risk groups.