Elderly people with low zinc levels benefited from three months of supplementation with 30 mg or zinc per day, with increases in serum zinc concentrations and an increase in the number of T cells, according to scientists from the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston University School of Medicine, Hebrew SeniorLife, and Harvard Medical School.
Average serum zinc concentration increases of 16% were reported in the zinc group, compared with the placebo group, they wrote, but not all zinc-deficient elderly reached adequate concentrations.
Writing in the American Journal of Clinical Nutrition, the researchers explained that they recruited 31 elderly people in nursing homes with low zinc levels (less than 70 micrograms per dL (ug/dL)) to participate in their randomized, double-blind, placebo-controlled study.
Results showed that while zinc supplementation increased zinc levels by about 16%, the daily 30 mg dose was not enough to increase zinc levels above the 70 ug/dL level in people with initial levels lower than 60 ug/dL.
“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,” they wrote.
“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.”
Source: American Journal of Clinical Nutrition
Published online ahead of print, doi: 10.3945/ajcn.115.115188
“Effect of zinc supplementation on serum zinc concentration and T cell proliferation in nursing home elderly: a randomized, double-blind, placebo-controlled trial”
Authors: J.B. Barnett, et al.