Zinc, Not Iron, For Pregnancy-induced Anemia

Anemia, or low red blood cell count, is one of the most common medical conditions among pregnant women and almost always calls for a megadose iron prescription. But zinc and iron are both required to build red blood cells (RBC), and deficiencies often occur concurrently. Now a Japanese study published in the Journal of the American College of Nutrition shows that supplementing with both minerals is more effective than either alone and that some prenatal anemia is due to a deficiency of zinc, not iron.

Researchers at Kumamota University School of Medicine placed 38 pregnant women into three groups for eight weeks: eleven took 34 mg/day zinc, 10 received 100 mg iron, and 17 took both supplements. Taking either zinc or iron alone did not change the average RBC counts, but the combination did.

Although average RBC levels did not change in the group given only zinc supplements, seven women's anemia improved while four worsened. Those who improved originally showed zinc deficiency but had adequate iron. The four women whose RBC levels dropped initially showed indications of iron deficiency, which worsened during the time they received only zinc supplements.

This makes sense because minerals compete for absorption. Consequently, it is not surprising that women with iron deficiencies worsened when receiving zinc supplements and vice versa.

Previous surveys show pregnant women's diets are woefully low in zinc. Food sources of zinc include red meat, shellfish (especially oysters), legumes and nuts. Iron is also found in meats as well as green leafy vegetables, dried beans and peas, and nuts and seeds.