context: Zinc is a mineral that's important to the body in many ways. Zinc keeps the immune system strong, helps heal wounds, and supports normal growth. Zinc deficiency occurs frequently in developing countries. Zinc deficiency in the U. S. is rare, because most diets provide more than the recommended dietary allowance. Zinc has become a popular treatment for the common cold. Some studies have found that zinc lozenges may reduce the duration of cold, perhaps by as much as 50%, and may reduce the number of upper respiratory infections in children. Zinc helps fight infection and heal wounds. However, if you already have enough zinc from your diet, it is not clear that getting even more -- from supplements -- has a benefit. Topical zinc is used to treat diaper rash and skin irritations. Zinc has also been shown to help with ulcers, ADHD, acne, sickle cell anemia, and other conditions. In addition, zinc has also been studied as a treatment for herpes, high cholesterol, rheumatoid arthritis, HIV, and more. However, the evidence of zinc's benefit for these conditions is inconclusive. Zinc may be part of an effective treatment for age-related macular degeneration, but more proof is needed. Health care providers may recommend zinc supplements for people who have zinc deficiencies. Strict vegetarians, breastfeeding women, alcohol abusers, and people who have a poor diet are at higher risk for zinc deficiency. So are those with certain digestive problems, such as Crohn's disease. The recommended dietary allowance ( RDA) includes the zinc you get from both the food you eat and any supplements you take. Category Recommended Dietary Allowance ( RDA) of Zinc CHILDREN 7 months to 3 years 3 mg/day 4-8 years 5 mg/day 9-13 years 8 mg/day FEMALES 14-18 years 9 mg/day 19 years and up 8 mg/day Pregnant 14-18 years: 12 mg/day19 years and over: 11 mg/day Breastfeeding 14-18 years: 13 mg/day19 years and over: 12 mg/day MALES 14 years and up 11 mg/day The tolerable upper intake level ( UL) of a supplement is the highest amount that most people can take safely. Never take more unless your health care provider says so. Keep in mind that this upper limit includes the zinc you get from foods and supplements. Category ( Children & Adults) Tolerable Upper Intake Level ( UL) of Zinc 0-6 months 4 mg/day 7-12 months 5 mg/day 1-3 years 7 mg/day 4-8 years 12 mg/day 9-13 years 23 mg/day 14-18 years 34 mg/day 19 years and up 40 mg/day To avoid irritating the stomach, take zinc with food. For the common cold, zinc lozenges -- 10 mg to 15 mg daily -- are supposed to be started within 24 hours of the onset of cold symptoms. Then, take the zinc lozenges every two to three hours until the symptoms go away. There are zinc supplements in pill and liquid form. Good food sources of zinc are: Red meat Poultry Oysters Fortified cereals Whole grains Beans and nuts Side effects. Zinc supplements can irritate the stomach and mouth. Zinc lozenges can alter your sense of smell and taste for a few days. If taken long-term, zinc lozenges may lower copper levels in the body. Zinc nasal sprays have been associated with a loss of smell, which may be permanent. Interactions. Zinc may interact with some medicines such as birth control pills and some antibiotics. Zinc can also interact with other supplements, such as calcium, magnesium, copper, and iron. If you take daily medicine or supplements, ask your health care provider about taking zinc. Risks. People who are allergic to zinc, have HIV, or have hemochromatosis should not take zinc supplements without talking to their doctor first. Too much zinc can cause fever, cough, nausea, reduced immune function, mineral imbalances, cholesterol changes, and other issues. In pregnant women, high doses may harm the fetus.