Zinc (Zn)

Zinc is an essential trace mineral found in the body in larger amounts than any other trace mineral, 1.8 grams, except iron, 5 grams. It has been recognized as essential to humans in 1960s when deficiency cases were first recognized. The mineral is absorbed throughout the small intestine mostly in the jejunum and absorption is influenced by the type of foods ingested. Absorption is more likely to be high if animal proteins are consumed, when body needs are higher and when dietary intake is low.

When absorption take place into intestinal cells a protein, metallothionein, binds zinc in similar way that ferritin binds iron and partly regulates its absorption. The largest stores of this trace mineral in the body are found in the pancreas, liver, voluntary muscles, and bones. It is also found in the eyes, skin, prostate gland, hair nails, and white blood cells. However, the absorbed amounts of the mineral in the body are classified as functional zinc and amounts held in storage are very small.

Zinc intakes are generally low worldwide. While insufficient dietary intake may be the cause of poor zinc status in some cases the most likely causative factor in depleted zinc status are inhibitors of its absorption. A high intake of phytic acid found in grains and high intake of calcium both decease absorption of this mineral. Some milk proteins have been shown to inhibit its absorption. Finally zinc competes with copper and iron in the body for absorption.

Zinc is present in every cell in the body and has many and diverse biological functions. More than 100 require zinc for optimal activity. The mineral supports many body functions such as: Protein metabolism, immune function, general growth, wound healing and burns, synthesis and function of nucleic acid, development of sexual organs, insulin function cell membranes structure and function and behavioral development in infants.
Severe deficiency is not common but marginal deficiency of zinc is and it is difficult to diagnose.

The signs and symptoms of deficiency are nonspecific and can include increased fatigue, decreased alertness, and inadequate growth, declined immune function, acne, delayed wound healing, decreased production of lymphocytes and decreased B and T lymphocyte responses. A high intake of this mineral interferes with copper and iron metabolism and increases the need for vitamin A intake.

The RDA for zinc is 11 mg/day for men and 8 mg/day for women and the upper level is 40 mg/day. In general protein rich diets are rich in zinc also. Foods with high content are oysters shrimp, beef, turkey, legumes. Nuts, whole grains, wheat germ and pumpkin seeds can provide substantial amounts. While food sources for zinc are the preferred sources, zinc supplements shown to be effective to maintain zinc status in those at risk of deficiency.

Health and Fitness A Health Choice Destination Online.
© 2008 Health and Fitness All Rights Reserved

Welcome back!