Riboflavin nutritional status and absorption in oral contraceptive users and nonusers.

Riboflavin nutritional status, based on erythrocyte glutathione reductase (EGR) determinations, and the absorption of the vitamin after 10-mg oral doses were assessed in a group of oral contraceptive users (group OC, n = 18) and in a group of nonusers (group NOC, n = 17). Before administration of test doses of riboflavin, mean EGR levels of 4.06 (group OC) and 4.44 (group NOC) mumoles glutathione reduced per minute per gram of hemoglobin were not significantly different. After oral administration of riboflavin, a significant increase in EGR levels was observed within each group although no significant differences were detected between groups. Mean EGR levels continued to be slightly lower for group OC compared to group NOC. Oral absorption of riboflavin based on urinary excretion results was not significantly different between the groups. These findings indicate OC use does not significantly affect riboflavin nutritional status in a subject population having adequate nutrition of moderate to high socioeconomic status. Significant reductions in EGR levels which have been previously reported for OC users appear to be associated with a low socioeconomic status.