Effect of zinc supplementation on serum zinc concentration and T cell proliferation in nursing home elderly: a randomized, double-blind, placebo-controlled trial

Am J Clin Nutr. 2016 Mar;103(3):942-51. doi: 10.3945/ajcn.115.115188. Epub 2016 Jan 27.


Background: Zinc is essential for the regulation of immune response. T cell function declines with age. Zinc supplementation has the potential to improve the serum zinc concentrations and immunity of nursing home elderly with a low serum zinc concentration.

Objective: We aimed to determine the effect of supplementation with 30 mg Zn/d for 3 mo on serum zinc concentrations of zinc-deficient nursing home elderly.

Design: This was a randomized, double-blind, placebo-controlled study. Of 53 nursing home elderly (aged ≥65 y) who met eligibility criteria, 58% had a low serum zinc concentration (serum zinc <70 μg/dL); these 31 were randomly assigned to zinc (30 mg Zn/d) (n = 16) or placebo (5 mg Zn/d) (n = 15) groups. The primary outcome measure was change in serum zinc concentrations between baseline and month 3. We also explored the effects of supplementation on immune response.

Results: Baseline characteristics were similar in the 2 groups. The difference in the mean change in serum zinc was significantly higher, by 16%, in the zinc group than in the placebo group (P = 0.007) when baseline zinc concentrations were controlled for. In addition, controlling for baseline C-reactive protein, copper, or albumin did not change the results. However, supplementation of participants with ≤60 μg serum Zn/dL failed to increase their serum zinc to ≥70 μg/dL. Zinc supplementation also significantly increased anti-CD3/CD28 and phytohemagglutinin-stimulated T cell proliferation, and the number of peripheral T cells (P < 0.05). When proliferation was expressed per number of T cells, the significant differences between groups were lost, suggesting that the zinc-induced enhancement of T cell proliferation was mainly due to an increase in the number of T cells.

Conclusions: Zinc supplementation at 30 mg/d for 3 mo is effective in increasing serum zinc concentrations in nursing home elderly; however, not all zinc-deficient elderly reached adequate concentrations. The increase in serum zinc concentration was associated with the enhancement of T cell function mainly because of an increase in the number of T cells.

Keywords: T cell proliferation; nursing home elderly; serum zinc concentration; zinc gluconate; zinc supplementation.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Aging* / blood
  • Aging* / immunology
  • Cell Proliferation / drug effects*
  • Deficiency Diseases / blood
  • Deficiency Diseases / prevention & control
  • Dietary Supplements*
  • Double-Blind Method
  • Female
  • Homes for the Aged
  • Humans
  • Lymphocyte Activation / drug effects*
  • Male
  • Nursing Homes
  • T-Lymphocytes / metabolism*
  • Trace Elements / blood
  • Trace Elements / deficiency
  • Trace Elements / pharmacology*
  • Trace Elements / therapeutic use
  • Zinc / blood
  • Zinc / deficiency
  • Zinc / pharmacology*
  • Zinc / therapeutic use


  • Trace Elements
  • Zinc