Zinc is an essential trace mineral that has many roles in the body. It promotes cell reproduction and the growth and repair of tissues. It is necessary for normal growth and development during pregnancy, childhood and adolescence.

Zinc is associated with more than 200 enzymes, including those that metabolize food and help the body use carbohydrates, proteins and fats. In recent years, people have begun to use zinc lozenges to fight common colds as they develop. Research is mixed as to the effectiveness of this approach.

The body absorbs zinc from animal products more easily than it absorbs zinc from plants. Zinc is highest in foods that are rich in protein, especially shellfish such as oysters, which provide more zinc per serving than any other food.

Average intakes of zinc in the United States actually exceed the suggested recommended daily amount. Zinc deficiency is relatively rare in developed countries. When it does occur, it can lead to severely impaired growth and lack of sexual development in children, among other symptoms.

Excessive levels of zinc also can cause illness, including reducing the body’s ability to absorb copper, impairing the immune system and causing greater vulnerability to infection. Extremely high doses of zinc cause symptoms of zinc poisoning, including vomiting, gastric upset, diarrhea, headaches, exhaustion and irritation to the stomach lining.

Zinc lozenges are commonly used to treat colds. Zinc supplements are often used in developing countries to treat childhood infectious diseases. People should not take zinc supplements without first consulting a physician.