Zinc Levels Not Affected by Iron Supplementation

DHAKA, Bangladesh--According to a study published in the Journal of Nutrition (135:2187-2191, 2005) joint supplementation with iron and zinc does not block increases in serum zinc in infants.

Bangladeshi researchers evaluated optimum strategies to simultaneously supplement iron and zinc in infants and young children deficient in both nutrients, as zinc can affect iron metabolism. This study evaluated the efficacy of weekly supplementation of iron or zinc or both on iron, zinc, and copper status in Bangladeshi infants. In a double blind, randomized, controlled community trial, infants aged six months were assigned weekly supplements of 1 mg riboflavin (control, n = 82) or 1 mg riboflavin + 20 mg iron (n = 83), 20 mg zinc (n = 83), or both (n = 85) for six months. Hemoglobin, serum ferritin, transferrin receptor, zinc and copper concentrations were measured at baseline and at the end of intervention. Serum Zn increased in both groups receiving zinc; the increase was greatest among children with low baseline serum zinc concentration. Iron status indicators did not differ among the groups before or after supplementation, however, supplementation with either zinc or iron decreased serum copper.

Researchers concluded joint supplementation with iron and zinc did not alter the nutrients' individual effects. However, they also determined the dosing regimen may not have been adequate to achieve the desired biochemical effects.