Ascorbic acid supplementation and regular consumption of fresh orange juice increase the ascorbic acid content of human milk: studies in European and African lactating women.

BACKGROUND Little is known about the influence of an increased intake of ascorbic acid (AA) on human milk AA output. OBJECTIVE We aimed to compare human milk AA content in European and African women and to evaluate the influence of increased AA intake on human milk AA output. DESIGN Apparently healthy lactating women were recruited. AA was analyzed by titration with 2,6-dichlorophenol-indophenol. RESULTS Mean human milk AA was approximately 50% lower (P < 0.001) in the African women (31 mg/kg; n = 171) than in the European women (63 mg/kg; n = 142). AA supplementation (1000 mg/d for 10 d) increased mean human milk AA from 19 to 60 mg/kg (P < 0.001) and from 60 to 70 mg/kg (P = 0.03) in 18 African and 10 European women, respectively. In 11 African women, mean human milk AA increased from 17 to 36 mg/kg (P < 0.001) after intake of 100 mg AA/d for 10 d. In African women, intake of 1 serving of orange juice per week had no significant effect, whereas 3 or 5 servings/wk ( approximately 100 mg AA/serving) for 6 wk increased mean human milk AA from 16 to 32 mg/kg (n = 13) and from 21 to 46 mg/kg (n = 13), respectively (P < 0.001). CONCLUSIONS Human milk AA can be doubled or tripled by increased intake of AA in women with low human milk AA content at baseline. The response to a relatively high dose of AA was modest in European women in contrast with the 3-fold increase in mean human milk AA content in African women. These data indicate that human milk AA content is regulated.