Evaluation of prenatal vitamin-mineral supplements.
Nutritional requirements of pregnancy are reviewed, and guidelines for evaluating prenatal vitamin-mineral supplements are provided. Daily antepartum supplementation of 0.4-0.8 mg of folic acid and 30-60 mg of elemental iron is currently recommended, although the lower ends of these ranges may be most appropriate. Dietary intake of these nutrients is likely to be inadequate without supplementation, and their importance is well established. Requirements for other minerals and vitamins are not well established, and there is no consensus on the need for supplementation. However, available data suggest that prenatal supplements should probably contain other nutrients; pyridoxine hydrochloride, cholecalciferol, vitamin E, pantothenic acid, calcium, magnesium, zinc, copper, and possibly selenium should be considered. Interactions among the minerals and vitamins commonly found in prenatal supplements may affect the absorption of various nutrient components. Thus, very high or low levels of certain nutrients should be avoided. The chemical form of minerals should also be considered. Products should have demonstrated bioavailability for iron, zinc, and other components that are subject to bioavailability problems. Use of low-potency product that contains a wide range of vitamins and minerals appears to be the most prudent approach to prenatal vitamin and mineral supplementation.