Is Zinc a Trace Mineral?

From a nutritionist's point of view, a mineral is a chemical element that is required by living organisms. According to Elson M. Haas, M.D., author of "Staying Healthy with Nutrition," there are 17 minerals that are essential for human health. These elements are arbitrarily classified as either macrominerals, meaning they must be obtained in relatively large amounts from your diet, or trace minerals, meaning that small amounts are needed for optimal health. Zinc is classified as a trace mineral.

Zinc Functions

Even though zinc is a trace mineral, it participates in an impressive number of functions in the human body. Zinc is a cofactor for a multitude of cellular enzymes, including alkaline phosphatase, which helps to maintain bone integrity; carboxypeptidase, which aids protein digestion; and dehydrogenases, which are involved in energy production and detoxification processes. Zinc is also incorporated into bones and teeth, and it is found in high concentrations in the eyes, liver, muscle, skin, hair, prostate and seminal fluid. The synthesis of DNA and RNA is dependent on zinc, and many immune functions are enhanced by zinc's presence.

Zinc Toxicity

Acute zinc toxicity is relatively uncommon, because only a certain amount of zinc from a large dose will be absorbed. A 1990 review in "The American Journal of Clinical Nutrition" describes the signs and symptoms of acute overdoses of zinc, which include nausea, vomiting, lethargy and abdominal pain. Chronic intake of excessive amounts of zinc can interfere with your body's absorption of other minerals, especially copper. This can lead to anemia, low white blood cell count, impaired immune function and abnormalities in blood lipid levels.

Zinc Deficiency

According to Haas, zinc deficiency is far more common than zinc toxicity. In part, this is due to a loss of zinc from agricultural soils and due to losses of zinc during food processing. Aging reduces your ability to absorb zinc. The Office of Dietary Supplements reports that the symptoms of zinc deficiency in children include growth retardation and delayed sexual maturation. Impaired immune function, loss of appetite, weight loss, hair loss, diarrhea, delayed wound healing, unusual taste sensations, fatigue, skin rashes and impotence are among the additional symptoms that can occur with zinc deficiency.

Sources and Recommendations

Food sources of zinc include meats, nuts, legumes and shellfish, especially oysters. Haas believes that it is difficult for someone who is eating a healthy diet to obtain the necessary daily requirements of zinc. Recommended daily allowances for zinc vary with age and gender, and zinc needs increase in pregnant women. Infants should get 2 to 3 mg of zinc daily; children, 5 mg; adolescents, around 10 mg; adult males, 11 mg; and adult females, 8 mg. Pregnant and nursing women who are under 18 should consume 13 mg and 14 mg, respectively, while older pregnant and nursing women should get 11 mg and 12 mg, respectively. Speak to your doctor if you think you need additional zinc.