is an essential mineral that is found in almost every cell of the body. It is necessary for proper growth and immune function. Oysters are well known for their zinc content, but other animal foods are excellent sources of zinc as well. You can also get zinc from plant-based foods, but this zinc is not as well absorbed.
Zinc's functions include:
Supporting normal growth and development during pregnancy, childhood, and adolescence
Playing a role in tissue repair
Helping the body use carbohydrate, protein, and fat
Helping to maintain proper immune function, including promoting wound healing
Serving as part of more than 70 enzymes that control body processes
Maintaining a sense of taste and smell
Maintaining normal vitamin A levels and usage
Recommended Dietary Allowance
4- 8 years
Pregnancy: < 18 years
Pregnancy: 19-50 years
Lactation: < 18 years
Lactation: 31-50 years
The human body is able to adapt to a short-term mild zinc deficiency by absorbing greater amounts from the foods you eat, and excreting less. However, sustained inadequate zinc intake will affect bodily functions. A zinc deficiency can have the following effects (but is relatively rare in the US except among people with general malnutrition):
Other conditions treated with nutrition given by vein
Zinc toxicity is rare in the US. However, people who take zinc supplements may reach toxic levels. Oversupplementation with zinc can cause a copper deficiency. Excess zinc may also cause the following:
Suppressed immune function
Impaired formation of red blood cells
Reduced levels of HDL ("good") cholesterol
Major Food Sources
Good sources of zinc include foods of animal origin, such as meat, seafood, and liver. Eggs and milk supply zinc in smaller amounts.
Some plant-based foods also contain zinc, but it is not absorbed as well by the body. Phytates found in plants can bind the zinc and decrease its absorption. Persons who eat large amounts of whole grain bread, especially those who eat few zinc containing foods listed below, may be at special risk. The zinc content of the soil in which these foods are grown also affects the zinc content of plant foods. In addition, many whole-grain foods contain zinc, but this zinc is removed when whole grains are refined.
Beef, ground lean, baked
Turkey, dark meat, no skin, roasted
Shrimp, cooked with moist heat
3 ounces (15 large shrimp)
Miso (fermented soybean)
Soybean nuts, dry roasted
Breakfast cereal (fortified with 25% of the daily value of zinc)
Tofu, raw, firm
Pinto beans, canned
Sunflower seeds, dry roasted
Mushrooms, shiitake, dried
Almonds, dry roasted
Infections and Wound Healing
Sufficient levels of zinc are essential for a properly functioning immune system. For example, zinc is required for the development and activity of T-lymphocytes, which are a type of white blood cell that helps fight infection.
When people deficient in zinc are given zinc supplements, biological markers of immunity improve. These effects are most clearly seen among children in emerging nations—when given zinc supplementation, they experience shorter courses of infectious diarrhea and may have less serious problems from
However, if someone is not deficient in zinc, taking zinc supplements does not improve wound healing or other functions of the immune system.
The Common Cold
Zinc lozenges, nasal sprays, and nasal gels may help to decrease the duration and severity of
symptoms. They are believed to directly inhibit viruses in the nose and throat. However, this topic is still controversial, since the findings from scientific studies have been mixed. Moreover, nasal gels and sprays may cause permanent smell loss when used incorrectly.
Those studies that have found a positive effect suggest beginning zinc at the first sign of a cold. The recommended dose is 13 to 23 mg of zinc as zinc gluconate or zinc acetate every 2 hours. This treatment should continue until symptoms subside, but never for longer than two weeks.
Also, lozenges that have citric acid or tartaric acid should be avoided. These acids are often added to improve flavor, but they can block zinc's antiviral action.
Absorption of Calcium, Iron, and Copper
Minerals can compete with one another for absorption in the body. This is especially a concern when they are taken at high doses, such as those in supplements.
If you take
supplements but consume little or no zinc, you might need to take a multivitamin/mineral containing zinc. Most multivitamin/mineral pills contain 100% of the RDA for zinc.
Large doses of zinc can interfere with the body's absorption of copper and
, other minerals that are essential to immune function. If you are taking a zinc supplement, talk to your doctor about your need for other supplements.
Please be aware that this information is provided to supplement the care
provided by your physician. It is neither intended nor implied to be a
substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER
IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the
advice of your physician or other qualified health provider prior to
starting any new treatment or with any questions you may have regarding a