Define the Importance of Zinc in Humans?
Zinc deficiency in humans was reported by A.S. Prasad among people consuming mostly breads and very little animal protein in Middle Eastern countries. Common manifestations of zinc deficiency were reduction in growth and appearance of skin lesions. In 1974, a genetic human disease-acrodermatitis enteropathica was related to an inability to absorb adequate zinc from the normal diet. The formal recognition of zinc as an essential nutrient came in 1974, when dietary allowances for nutrients were made.
In the biological systems, zinc is always found in the divalent (+2) state. Zinc is present in all body tissues and fluids. The total body zinc content has been estimated to be 30 mmol (2 g). Skeletal muscle accounts for approximately 60% of the total body content and bone mass, with a zinc concentration of 1.5-3 μmol/g (100-200 μg/g), for approximately 30%. The concentration of zinc in lean body mass is approximately 0.46 μmol/g (30 μg/g). Plasma zinc has a rapid turnover rate and it represents only about 0.1% of total body zinc content. This level appears to be under close homeostatic control. High concentrations of zinc are found in the choroid of the eye (4.2 μmol/g or 274 μg/g) and in prostatic fluids (4.6-7.7 mmol/l or 300 - 500 mg/L).