Zinc functions in association with more than 300 different enzymes involved in either synthesis or catabolism of carbohydrates, lipids, proteins, and nucleic acids. This trace mineral has a structural role in several proteins. Zinc is also involved in transport processes, immune function, insulin function, and gene expression. Although widely promoted to cure or prevent the common cold, zinc- containing products such as lozenges do not appear to be effective [10].

The most widely available form of zinc occurs in red meat and poultry. Meat intake is frequently low in preschoolers, which has led to fortification of infant and children’s foods, especially cereals, with zinc. Although milk is a good source of zinc, a high intake interferes with the absorption of iron and zinc. The phytates from whole grains in unleavened breads may limit zinc absorption. Zinc deficiency is common in developing countries. In Western nations, those most at risk include individuals with alcoholism, pregnant women, older adults, and athletes. Zinc deficiency results in various immunologic defects such as deficient thymic hormone activity. Excess zinc supplementation can interfere with copper absorption and result in an iron imbalance. Zinc sulfate in excess of 2 g/day may cause gastrointestinal irritation and vomiting.

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