Zinc is relevant to the maintenance of brain functions. It is involved in glutaminergic transmission in the gene expression of transcriptional factors and in nerve growth factor activity. Zinc turnover in the brain is mediated by metallothionein (MT) and the zinc traffic into the brain is due to ZnTl-4 transporter proteins. Alterations in zinc turnover lead to brain dysfunction. During aging, zinc turnover is altered, coupled with decreased brain functions and impaired cognitive performances. This decrease may lead to neurodegeneration. One of the causes of altered zinc turnover in aging may be due to altered zinc-bound MT homeostasis, which transforms from being a protective shield against stress into a harmful factor in aging because of the exclusive sequestration of zinc and lack of subsequent zinc release by MT for brain functions. The beneficial effect of zinc supplementation is discussed in aging and neurodegeneration.
