The Effect of Oral Contraceptives on Micronutrients

Abstract

In order to determine the effects of oral contraceptive use on mineral and vitamin metabolism, a large number of subjects of 2 different socioeconomic groups and 4 different hormonal states were studies for clinical, nutritional, and biochemical differences. Further subdivision of subjects occurred among those taking vitamin and/or mineral supplements. The hormonal states were 1) nonuse, 2) Norinyl use, 3) Ovral use, and 4) resumed use of oral contraceptives within 5 weeks postpartum during lactation. More of the clinical signs related to malnutrition were seen in the lower than in the higher socioeconomic groups and in the nonsupplemented than in the supplemented subjects of the lower socioeconomic group. Oral contraceptive users in the higher socioeconomic group showed more clinical signs of malnutrition than did controls. The oral contraceptive users' intake of calories, protein, calcium, magnesium, iron, copper, zinc, Vitamin A, C, B6, and folic acid did not differ from that of controls. Use of oral contraceptives did not affect hemoglobin, hematocrit, and erythrocyte count; plasma calcium, magnesium, and erythrocyte magnesium; plasma total protein; plasma ascorbic acid; or serum Vitamin B12. Oral contraceptive use was associated with increases in serum iron, total iron binding capacity, plasma copper, erythrocyte zinc, and plasma Vitamin A. Decreases in plasma zinc, serum albumin, and carotene levels were found, and lower urinary excretion of thiamin and riboflavin, plasma pyridoxal phosphate, red cell and serum folate were seen in the oral contraceptive users of the higher socioeconomic group. Both socioeconomic groups showed reduced erythrocyte glutamic oxalacetic transminase (EGOT) activity and elevation in the EGOT stimulation test suggesting a B6 and folic acid deficiency in users.