Impact Of Zinc Supplementation On T Cell Function In Zinc Deficient Elderly Nursing Home Residents

Previously we showed that 30% of nursing home elders (NHE) had low serum zinc (Zn) levels, which was strongly associated with increased incidence and duration of pneumonia (PNA). We hypothesized that Zn supplementation will enhance immune response in Zn deficient NHE. In this randomized, double-blind, placebo-controlled trial we studied the effect of Zn supplementation of Zn deficient (<70 μg/dl) NHE (>65 y) on T cell function. Participants received 30 mg/d Zn (n=11) or 5 mg/d Zn for placebo (n=12) plus 1/2 DRIs of essential nutrients for 3 mo. We observed increased lymphocyte proliferation in the supplemented group vs. the placebo group when stimulating peripheral blood lymphocytes with anti-CD3/CD28 or PHA (p=0.01, p=0.03, respectively; Student's t test). In addition, FACS analysis showed a significant increase in % CD4 T cell in the Zn group (p=0.04). Serum Zn levels in the Zn-supplemented group significantly increased by 11.7 ± 4.5 μg/dl (p=0.03). A significant positive association between the change in serum Zn and the change in T cell proliferation was observed (r=0.5, p=0.03, by Pearson correlation coefficient). Supplementation of Zn deficient NHE with 30 mg/day Zn for 3 mo significantly increases serum Zn level and improves T cell function. Future studies are needed to determine whether these changes translate into reducing the incidence and duration of PNA in NHE. Supported by USDA (58-1950-7-707). Grant Funding Source: USDA