The dynamic link between the integrity of the immune system and zinc status

The results of more than three decades of work indicate that zinc deficienc y rapidly diminishes antibody- and cell-mediated responses in both humans a nd animals. The moderate deficiencies in zinc noted in sickle cell anemia, renal disease, chronic gastrointestinal disorders and acrodermatitis entero pathica; subjects with human immunodeficiency virus; children with diarrhea ; and elderly persons can greatly alter host defense systems, leading to in creases in opportunistic infections and mortality rates. Conversely, short periods of zinc supplementation substantially improve immune defense in ind ividuals with these diseases. Mouse models demonstrate that 30 d of subopti mal intake of zinc can lead to 30-80% losses in defense capacity. Collectiv ely, the data clearly demonstrate that immune integrity is tightly linked t o zinc status. Lymphopenia and thymic atrophy, which were the early hallmar ks of zinc deficiency, are now known to be due to high losses of precursor T and B cells in the bone marrow. This ultimately leads to lymphopenia or a failure to replenish the lymphocytic system. Glucocorticoid-mediated apopt osis induced by zinc deficiency causes down-regulation of lymphopoiesis. In deed, zinc itself can modulate death processes in precursor lymphocytes. Fi nally, there is substantial evidence that zinc supplementation may well red uce the impact of many of the aforementioned diseases by preventing the dis mantling of the immune system. The latter represents an important area for research.