Riboflavin requirements of lactating Gambian women: a controlled supplementation trial.

As part of a study to determine the minimum allowance of riboflavin which is adequate for lactating women in a rural African environment, 60 subjects living in two Gambian villages were given either 2 mg riboflavin or a placebo daily on a double-blind basis for 12 wk. Their riboflavin intake from dietary sources was about 0.5 mg/day. In the supplemented group, the mean activation coefficient (AC) of erythrocyte glutathione reductase fell from 1.62 to 1.19 within 3 wk, and 90% had mean AC's below 1.3 throughout supplementation, whereas the placebo group maintained mean AC's between 1.6 and 1.9. Clinical signs associated with riboflavin deficiency improved more rapidly in the supplemented group; their breast milk riboflavin levels increased, and their infants' AC's were reduced, compared with those of the placebo group. After withdrawal of the supplement, the maternal and infants' AC's rose toward those of the placebo group. Thus a total riboflavin intake of about 2.5 mg/day during lactation is sufficient to maintain normal biochemical status in most Gambian women.