There are about two grams of zinc in the body where it is highly concentrated in the hair, skin, eyes, nails and testes. It is a constituent of many enzymes involved in mertabolism. Zinc is a precious mineral. Our need for this mineral is small but its role in growth and well-being is enormous, starting before birth. It is needed for healthy skin and hair, proper healing of wounds, successful pregnancies and male virility. It plays a vital role in guarding against diseases and infection. It is needed to transport vitamin A to the retina.
There are 156 enzymes that require zinc for their functioning. It has long been known that growth and sexual maturity depend on zinc. The main dietary sources of zinc are milk, liver, beans, meat, whole grains, nuts, and seeds. The recommended dietary allowance of zinc is 15 mg. daily. Deficiency can result in weight loss, skin diseases, hair loss, poor appetite, diarrhoea and frequent infection. Those suffering from rheumatoid arthritis may have a zinc deficiency. Heavy drinkers lose a lot of zinc in their urine.
More than half of the body's zinc supply is found in muscle tissue. This mineral is also found in other parts of the body, which include the bones, eyes, prostate gland, testes, skin and kidneys.
Since minerals may compete for absorption sites in the intestine, excess intakes of iron or copper can adversely interfere with zinc absorption. Likewise, excess intake of zinc (from supplements or fortified foods) can impair iron and copper absorption.
Although phytates and fiber found in unprocessed grains inhibit the bioavailability of zinc, whole grains are still a better source of zinc than that found in refined grains (e.g. white bread). Whole grain yeast breads enhance the absorption of zinc by producing enzymes that destroy phytates. Zinc from meat products, on the other hand, is four times more bioavailable than that found in fibrous grain foods.
The body best absorbs smaller amounts of zinc at one time. Overall, the body absorbs 15-40% of dietary zinc, depending on the body's requirement for this mineral.
Zinc - Minerals Health Nutrition
