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The importance of Zinc for Human Health

.Zinc is essential for human health and plays a key role in human metabolism.

For example, zinc is vital for the proper functioning of more the 200 enzymes, for the stabilisation of DNA and the expression of genes, and for the transfer of nervous signals.

The human body contains 2-3 g of zinc (compared with 7 g of iron) which is found everywhere in the body, with the highest levels in muscles, liver, kidneys, bones and prostate.

The recommended daily zinc intake in 12 mg/day for adult women and 15 mg/day for adult men. Daily intake is not only dependent on food, but also on sex, age and general health status. World Health Organisation (WHO), recommendations for the daily intake of zinc are listed in Table 1. Growing infants, children, adolescents, women in pregnancy and the elderly have a higher zinc requirement. Certain groups are known to have an increased demand for zinc and have a higher risk of not getting enough zinc (Table 2).

Food is the primary source of zinc for man, with only a small part coming from drinking water. Food products differ in their zinc content. The major sources of zinc in the diet are red meat, poultry, fish, seafood, whole cereals and dairy products.

Table 1: WHO Recommended daily allowance for zinc

Age Group	Recommended Intake
Infant 1-10 years Adult Male Adult Female Pregnant Female	5 mg 10 mg 15 mg 12 mg 15 mg

Table 2: Population groups with increased demand for zinc

Zinc is essential for human health but many adults and children may not be getting enough zinc in their diets. A comprehensive review (Walsh et al. 1995) of current knowledge about zinc and human health concluded that there is a potential for zinc deficiency on a worldwide scale.

In the United States, studies concluded that a substantial part of the general population is at risk from zinc deficiency. Mild chronic deficiency is even predicted in people consuming low meat diets rich in phyllite and fibre. Symptoms of zinc deficiency include reduced sense of taste and smell, skin disorders, mental lethargy and reduced fertility.

Zinc nutritional supplements can successfully balance insufficient dietary zinc intake but high doses can lead to gastro-intentional disorders and are not recommended without medical advice.