Zinc deficiency in Mexican American children: Influence of zinc and other micronutrients on T cells, cytokines, and antiinflammatory plasma proteins

Background: The Third National Health and Nutrition Examination Survey suggested some Mexican American children are at risk of zinc deficiency. Objective: We measured the effects of zinc and micronutrients or of micronutrients alone on indexes of cell-mediated immunity and antiinflammatory plasma proteins. Design: Subjects (n = 54) aged 6-7 y were randomly assigned and treated in double-blind fashion in equal numbers with 20 mg Zn (as sulfate) and micronutrients or with micronutrients alone 5 d/wk for 10 wk. Results: Before treatment the mean ± SD plasma zinc was 14.9 ± 1.7 μmol/dL and the range was within the reference; hair zinc was 1.78 ± 0.52 μmol/g and 41.6% were ≤ 1.68 μmol/g; serum ferritin was 25.7 ± 18.6 μg/L and 50.0% were ≤20 μg/L. The zinc and micronutrients treatment increased the lymphocyte ratios of CD4⁺ to CD8⁺ and of CD4⁺CD45RA⁺ to CD4⁺CD45RO⁺, increased the ex vivo generation of interleukin-2 (IL-2) and interferon-γ (IFN-γ), decreased the generation of interleukin-10 (IL-10), and increased plasma interleukin-1 receptor antagonist (sIL-lra) and soluble tumor necrosis factor receptor 1 (sTNF-R1). Micronutrients alone increased the ratio of CD4⁺ to CD8⁺ but not of CD4⁺CD45RA⁺ to CD4⁺CD45RO⁺, increased IFN-γ but had no effect on IL-2 or IL-10, and increased sIL-lra but not sTNF-R1. Efficacy of zinc and micronutrients was greater than micronutrients alone for all indexes except the ratio of CD4⁺ to CD8⁺, which was affected similarly. Conclusions: Before treatment, concentrations of hair zinc in 41.6% of subjects and serum ferritin in 50% were consistent with the presence of zinc deficiency. The greater efficacy of the zinc and micronutrients treatment compared with micronutrients alone supports this interpretation.