Submitted to: Food and Nutrition Bulletin
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/26/2009
Publication Date: 12/26/2009
Citation: Allen, L.H., Peerson, J.M. 2009. Impact of multiple micronutrient vs. iron - folic acid supplements on maternal anemia and micronutrient status in pregnancy. Food and Nutrition Bulletin. Vol. 30, No. 4. Interpretive Summary: This paper reviews data from studies in which pregnant women were supplemented with multiple micronutrients (minerals and vitamins) compared to just iron, or iron + folic acid, as part of a UNICEF-World Health Organization review of micronutrient supplementation trials in pregnancy. Theoretically, the additional minerals and vitamins present in multiple micronutrient supplements might support hemoglobin synthesis, and reduce anemia, more than iron ± folic acid alone. However, this pooled analysis found no effect of the additional micronutrients on maternal hemoglobin, anemia or iron status compared to iron ± folic acid. Nor did the multiple supplements increase serum retinol or zinc levels in serum. In the one study where these and other micronutrient concentrations were all measured in maternal serum, a high prevalence of multiple deficiencies of minerals and vitamins persisted in the mothers supplemented with multiple micronutrients. More research is needed on the amounts of micronutrients that should be provided in pregnancy supplements for micronutrient-deficient women.
Technical Abstract: Background. Multiple micronutrient (MMN) supplements could increase hemoglobin and improve micronutrient status of pregnant women more than iron ± folic acid supplements alone. Objective. To compare the effects of MMN vs. iron ± folic acid supplements on hemoglobin and micronutrient status of pregnant women. Methods. Studies were identified in which women were randomized to treatment with MMN or iron ± folic acid during pregnancy. A pooled analysis was conducted to compare the effects of MMN to iron ± folic acid on maternal hemoglobin, anemia and micronutrient status. The effect size was calculated for hemoglobin and micronutrient status indicators in each study, and for all studies combined, based on the mean change from baseline to final measure in the iron ± folic acid group minus the mean change in the MMN group, divided by the pooled standard deviation of the two groups. The effect on the relative risk of anemia and iron deficiency was calculated as the probability of anemia or iron deficiency in the MMN group divided by the probability in the iron ± folic acid group. Results. The MMN supplements did not increase hemoglobin or improve iron or vitamin A status indicators more than the same amount of iron ± folic acid. There was also no overall effect on serum retinol or serum zinc, although these measures were assessed in relatively few studies. In the single study in which changes in maternal status of several other micronutrients were analyzed, a high prevalence of multiple deficiencies persisted in the MMN group provided with approximately the daily recommended intake of each nutrient. Conclusions. MMN supplements do not have an additional impact on hemoglobin synthesis during pregnancy compared to iron ± folic acid supplements alone. In general there was no or small impact on the status of other micronutrients, suggesting that more research is needed on the amount of nutrients that should be provided in supplements by pregnant women with micronutrient deficiencies.