Zinc in human nutrition: Requirement and bioavailability - an overview
1992
Khan, A. (NWFP Agricultural Univ., Peshawar (Pakistan). Dept. of Human Nutrition)
Zinc is an essential micronutrient for both plants and animals. It is present in every tissue of the body, component of protein and nucleic acids and a cofactor for major metabolic enzymes. Its deficiency has a variety of biochemical and physiological effects in human health. The metabolic need of zinc is 6 mg for an adult per day. The bioavailability of zinc is affected by endogenous and exogenous factors. The endogenous factors are zinc status of the body, presence of metallothionine in the intestine, receptor sites on the basolateral membrane, presence of metal free albumin and age of the animal. The exogenous factors include protein type, certain amino acids, fiber, phytic acid, minerals, pH of the intestine, heat treatment and processing of foods. Phytic acid/zinc and phytic acid x calcium/zinc molar rations affect zinc absorption. Adaptation of the animal to the food increases zinc absorption. These factors should be considered when evaluating the bioavailability of zinc from food stuff.
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