Efficacy of Daily Consumption of Sweet Potatoes for Increasing Total Body Vitamin A Pool Size, and the Effect of Consumption of Sweet Potatoes on Iron and Zinc Absorption in Bangladeshi Women of Reproductive Age

Biofortification of plant source foods is a promising strategy for increasing dietary vitamin A intake and vitamin A status in populations at risk of deficiency. The primary purposes of this study are:

1. to assess the efficacy of daily consumption of boiled or fried orange-fleshed sweet potatoes (OFSP) for increasing the vitamin A status of non-pregnant, non-lactating Bangladeshi women, and
2. to estimate the relative vitamin A equivalency of beta-carotene from the two different preparations of OFSP (boiled or fried).

Secondary purposes are to assess the effect of daily consumption of OFSP on intestinal absorption of iron and zinc. Specifically, 120 non-pregnant, non-lactating women at risk of vitamin A deficiency will be randomly assigned to one of the following 4 treatment groups to receive, 600 micrograms RAE/d, 6 d/wk, for 60 days as either:

1. boiled OFSP
2. fried OFSP
3. retinyl palmitate, or 0 micrograms RAE/d as white-fleshed sweet potato (WFSP)

The paired stable isotope dilution technique will be used to estimate total body vitamin A pool size before and after 60-days of supplementation. The efficacy of consumption of OFSP will be assessed by comparing the mean change in vitamin A pool size in the OFSP groups to the mean change in vitamin A pool size in the negative control group (WFSP group). Relative vitamin A equivalency factors will be estimated by comparing the mean change in vitamin A pool size in the OFSP groups with the mean change in vitamin A pool size in the retinyl palmitate group. Intestinal iron absorption and iron status will be assessed before and after the 60-day supplementation period in a subset of women (n=50); and intestinal zinc absorption and zinc status will be assessed after the 60-day supplementation period (n=50). Intestinal absorption of iron and zinc will be compared by treatment group to determine whether consumption of OFSP has any effect on iron or zinc absorption in these women.