The contribution of plant foods to the vitamin A supply of lactating women in Vietnam: a randomized controlled trial

More information is needed on the efficacy of carotenoids from plant foods in improving vitamin A status. We aimed to quantify the efficacy of provitamin A-rich vegetables and fruit in improving vitamin A status. Breastfeeding women in 9 rural communes in Vietnam were randomly allocated to 1 of 4 groups: the vegetable group (n = 73) which ingested 5.6 mg s-carotene/d from green leafy vegetables; the fruit group (n = 69) which ingested 4.8 mg s-carotene/d from orange or yellow fruit; the retinol-rich group (n = 70) which ingested 610mcgg retinol/d from animal foods and 0.6 mg s-carotene/d; and the control group (n=68) which ingested 0.4 mg s-carotene/d. Meals of groups 1 2 and 4 contained -30 mcgg retinol/d. Lunch and dinner were provided 6 d/wk for 10 wk. Mean (95% CI) changes in serum retinol concentrations of the vegetable fruit retinol-rich and control groups were 0.09 (0.03 0.16) 0.13 (0.07 0.19) 0.25 (0.17 0.33) and 0.00 (-0.06 0.06) mcgmol/L respectively. Mean (95% CI) changes in breast-milk retinol concentrations were 0.15 (0.04 0.27) 0.15 (0.02 0.28) 0.48 (0.32 0.64) and -0.06 (-0.21 0.09) mcgmol/L respectively. According to these findings the equivalent of 1 mcgg retinol would be 12 mcgg s-carotene (95% CI: 8 22 mcgg) for fruit and 28 mcgg s-carotene (17 84mcgg) for green leafy vegetables. Thus apparent mean vitamin A activity of carotenoids in fruit and in leafy vegetables was 50% (95% CI: 27% 75%) and 21% (7% 35%) respectively of that assumed. The bioavailability of carotenoids from vegetables and fruit is less than previously assumed. (authors)