An Introduction to Zinc and its Benefits
Zinc is an essential trace mineral found throughout the body, often in conjunction with protein. Zinc is transported in the blood via the protein albumin, so low albumin levels often mean poor absorption of zinc as well.
Zinc is a cofactor used to activate dozens of enzymes in every organ in the body. Bones, the prostate gland in men, and the eyes have the highest concentrations of zinc, but about 60% of total zinc in the body is found in muscle.
Among the many roles of zinc is its support of the immune system and its ability to help the body heal wounds. Zinc is also essential to the senses of taste and smell. DNA cannot be synthesized without zinc, and zinc is also necessary for growth and development from gestation through adolescence.
Adults need between 8 and 15 mg of zinc per day to maintain health. Zinc is found in many foods, with oysters at the top of the list in terms of the amount of zinc per serving. Meat and poultry are excellent sources of zinc as well. Zinc is also found in beans, nuts, whole grains, and fortified breakfast cereals.
It appears that zinc is best absorbed through food when the diet is high in animal protein, so zinc deficiency can be a concern for vegetarians. Phytates, substances found in whole grains and beans, bind zinc and decrease absorption of the mineral. As a result, vegetarians need about 50% more zinc than non-vegetarians, since the zinc from plant sources is not absorbed as easily as the zinc in animal protein.
Zinc deficiency is also fairly widespread among certain other groups, including alcoholics and pregnant women. People on low calorie diets are usually at risk for inadequate zinc intake as well.
Even in the general population, dietary intake of zinc is not always adequate. Symptoms of zinc deficiency include arrested sexual maturation, digestive disorders, hair loss, slow wound healing, and poor sense of taste and smell. Zinc deficiency can also contribute to impaired immunity, resulting in frequent colds and infections. Eventually, zinc deficiency can affect the central nervous system and brain function.
People at risk for zinc deficiency may benefit from supplements.
In addition, zinc supplements are often recommended to boost the immune system, and many people use zinc lozenges to ward off colds at the first sign of symptoms like coughing or sneezing. The usual dosage of zinc supplements is 30 mg per day. Many experts recommended taking greater amounts to reduce cold symptoms, but total intake should not be more than 150 mg per day. Too much zinc can interfere with iron and copper absorption, so it is important to ensure a balanced intake of these minerals, whether from supplements or food.
One form of zinc, called zinc monomethionine aspartate is an integral part of a supplement, ZMA, which is touted by retailers of bodybuilding products as a “testosterone booster.”
Side effects of zinc supplements may include nausea, stomachache, or a metallic taste in the mouth.