Zinc is an essential mineral and has a multitude of biological roles because it is a functional component of over 300 enzymes that rely on zinc to be able to catalyze chemical reactions. Zinc also participates in the structure of important proteins and is involved in the regulation of gene expression.
Zinc is obtained from the diet. Oysters contain substantially more zinc than any other food, although red meat (e.g., beef, pork) and poultry provide the majority of zinc in the American diet. Other good sources of zinc are legumes, nuts, and dairy products. In some countries, the flour used in cereals are fortified with zinc.
The potential benefits derived from supplementation with zinc seem to be at least partly attributable to zinc’s anti-inflammatory and antioxidant properties. Zinc supplementation has been shown to reduce the duration of respiratory tract infections and the common cold.
Adequate dietary intake of zinc is essential for proper growth and development during pregnancy and throughout infancy, childhood, and adulthood. Additionally, zinc is required for normal development, activity, and function of both innate and adaptive immune cells; proper function of pancreatic beta-cells and glucose uptake; and spermatogenesis and normal sperm physiology (e.g., sperm motility).
In the brain, zinc ions inhibit N-methyl-D-aspartate (NMDA) receptors, which is relevant to depression because this condition is characterized by elevated glutamatergic neurotransmission (to which NMDA receptors contribute). Zinc may also benefit depression by increasing brain-derived neurotrophic factor levels.