To the Editor.
—We find the study by Dr Goldenberg and colleagues1 on the effect of zinc supplementation on pregnancy outcome in poor African—American women ethically troublesome because the pregnant women whose diets had less than the recommended dietary allowance (RDA) of 15 mg of zinc per day were deprived of this essential nutrient as a supplement.In addition, the diets of the study participants were not assessed for phytate and fiber, which are associated with low bioavailability of dietary zinc.2 The authors cite references that indicate zinc is an essential nutrient.3 The National Research Council has documented that dietary zinc deficiency in humans causes growth retardation and immunological abnormalities.4Most women in this study did not seek prenatal care until they were approximately 19 weeks pregnant. The plasma zinc levels of these women were already below the median for this population. Health care professionals are
Ginsberg HN, Karmally W. Zinc Supplementation During Pregnancy. JAMA. 1995;274(24):1909-1910. doi:10.1001/jama.1995.03530240019022