Oral Zinc Supplementation Decreases the Serum Iron Concentration in Healthy Schoolchildren: A Pilot Study

Abstract

The recognized antagonistic actions between zinc and iron prompted us to study this subject in children. A convenience sample was used. Thirty healthy children between 8 and 9 years of age were studied with the aim of establishing the effect of a 3-mo oral zinc supplementation on iron status. Fifteen individuals were given a placebo (control group), and 15 were given 10 mg Zn/day (experimental group). Blood samples were collected at 0, 60, 120, 180 and 210 min after a 12-h overnight fast, before and after placebo or zinc supplementation. This supplementation was associated with significant improvements in energy, protein, fat, carbohydrate, fiber, calcium, iron, and zinc intake in accordance with the recommendations for age and sex. The basal serum zinc concentration significantly increased after oral zinc supplementation (p < 0.001). However, basal serum iron concentrations and area under the iron curves significantly decreased in the experimental group (p < 0.0001) and remained at the same level throughout the 210-min study. The values obtained for hemoglobin, mean corpuscular volume, ferritin, transferrin, transferrin saturation, ceruloplasmin and total protein were within normal reference ranges. In conclusion, the decrease in serum iron was likely due to the effects of chronic zinc administration, and the decrease in serum iron was not sufficient to cause anemia.

The Effect of Low Dose Iron and Zinc Intake on Child Micronutrient Status and Development during the First 1000 Days of Life: A Systematic Review and Meta-Analysis

“…Lastly, we found that, when zinc and iron were given together, their beneficial effects on serum zinc and serum iron levels were weaker than when each nutrient was given alone, suggesting that iron and zinc compete for absorption from the gut, a finding that has previously been posited [116]. …”

Evaluation of iron transport from ferrous glycinate liposomes using Caco-2 cell model

“…The results implied that liposomes could improve the anti-inhibition of iron. Plenty of literature evidenced that the interaction of iron and zinc in foods was antagonistic effect, which would cause the reduction in bioavailability of the two mineral elements 29 , 30 . Espinoza et al and Iyengar et al reported that divalent metal transporter 1 (DMT1) and/or Zip14 (Zrt- and Irt-like protein 14) were the probable iron and zinc interaction site 31 , 32 .…”

Dietary zinc supplementation increased TNFα and IL1β-induced RANKL expression, resulting in a decrease in bone mineral density in rats

“…( 6 , 7 ) Since serum iron is considered an iron status indicator, our finding would be of value in terms of the therapeutic effect of zinc supplementation. De Brito et al ( 26 ) reported that oral zinc supplementation, which did not exceed the estimated average requirement and the tolerable upper intake level, inhibited iron absorption and decreased the serum iron concentration in healthy schoolchildren, but did not decrease hematological parameters or promote anemia. In contrast, several other studies have demonstrated a significant decrease in iron status indicators, such as hematological and biochemical parameters, in infants supplemented with zinc.…”