Serum vitamin A, carotene and cholesterol levels in Nigerian women using various types of contraceptives.

The diet in southern Nigeria is unusually high in carotenoids and low in preformed vitamin A. We studied the changes in serum vitamin A carotene and cholesterol induced in women in this region by the use of 3 types of contraceptives: IUD, injectable progestogen (INJ), and oral combination estrogen-progestogen (OC). The mean serum vitamin A and carotene levels were high in all groups. As expected, the serum vitamin A level in OC users was higher than in the other groups, but unexpectedly, the serum vitamin A was lower in IUD users. Serum carotene was lower in OC users than in other groups. Serum cholesterol was lower in the IUD and INJ groups than in the control and OC groups. A more detailed study of plasma transport forms of vitamin A is needed to determine if the very high serum vitamin A levels seen in some OC users in this population are potentially harmful.