Impact of the discovery of human zinc deficiency on health.

The essentiality of zinc in humans was established in 1963. During the past 50y, tremendous advances in both clinical and basic sciences of zinc metabolism in humans have been observed. Growth retardation; cell-mediated immune dysfunction, and cognitive impairment are major clinical effects in human. At present we know of >300 enzymes and >1000 transcription factors that require zinc for their activities. Zinc is a second messenger of immune cells, and intracellular free zinc in these cells participate in signaling events. Zinc has been very successfully used as a therapeutic modality for the management of acute diarrhea in children, Wilson's disease, the common cold and for the prevention of blindness in patients with age-related dry type of macular degeneration. Zinc not only modulates cell-mediated immunity but is also an antioxidant and anti-inflammatory agent. Zinc supplementation in the elderly results in decreased incidence of infections, decreased oxidative stress and decreased generation of inflammatory cytokines.