From The November 1999 Issue of Nutrition Science News
Anemia, or low red blood cell count, is one of the most common medical conditions among pregnant women and almost inevitably secures a woman 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 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.
Soruku Nishiyama, M.D., of Kumamota University School of Medicine placed 38 pregnant women into three groups: 11 took 34 mg/day zinc, 10 received 100 mg iron, and 17 took both supplements for eight weeks. Taking either zinc or iron alone did not change the average RBC counts, but the combination did; it also raised average hemoglobin levels from 10.3 to 11. Increasing red blood cells generally raises hemoglobin.
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 biochemical indications of zinc deficiency but had adequate serum ferritin, a marker of iron status. The four women whose RBC levels dropped even further initially showed indications of iron deficiency, which worsened during the time they received only zinc supplements.
Since minerals compete for absorption, it is not surprising that zinc levels in those given iron supplements alone also declined during the study.
Previous surveys show pregnant women's diets are woefully low in zinc. This study suggests anemic patients should be counseled about eating diets high in both zinc and iron, rather than simply taking iron supplements. 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, nuts and seeds.
Zinc and IGF-I Concentrations in Pregnant Women with Anemia Before and After Supplementation with Iron and/or Zinc
Journal of the American College of Nutrition 1999 (Jun); 18 (3): 261—267