Globally, a widespread nutritional deficiency of zinc is observed throughout the developing countries. Also, a conditioned deficiency of zinc is identified to happen in several diseased states. Zinc is recognized to play a significant role in the immune system and people who are zinc deficient might experience increased predisposition to a variety of pathogens.

The effects of a mild deficiency of zinc on T cells has been studied in an experimental model of human zinc deficiency. It showed that T cell functions were adversely affected even though the deficiency of zinc level was mild in humans. During zinc deficiency, the serum thymulin activity (a thymic hormone) was characteristically decreased and was restored soon following the supplementation of zinc.

Also, the studies showed that zinc deficiency did cause an imbalance between TH1 and TH2 functions. The production of IFN-g, IL-2, TNF-a are products of TH1 cells were also reduced, while the production of IL-4, IL-6 and IL-10, products of TH2 were not affected in zinc deficiency. T cell subpopulation studies have also revealed that the CD4+ CD45RA+ to CD4+ CD45RO+ ratio decreased due to zinc deficiency, thus suggesting that zinc supplementation might be required for the regeneration of new CD4+ T cells. It was also documented that zinc deficiency decreases the NK cell lytic activity and causes a reduction in the percentage of CD8+ CD73+ T cells that are known to be mostly precursors of cytotoxic T cells. The immunological effects of zinc deficiency could be responsible for decreased cell mediated immune functions in zinc deficient population.

Source: Prasad AS. Zinc and immunity. Mol Cell Biochem. 1998;188(1-2):63-69.