Editor's note: As the cold and flu season continues, we provide some facts about zinc from the National Institutes of Health Office of Dietary Supplements
Zinc is a mineral that your body needs for many things, including a healthy immune system and to make proteins and DNA. Zinc also helps the body grow and develop during pregnancy, infancy, childhood, and adolescence.
Meat, fish, other seafood (especially oysters), and poultry are all good sources of zinc. You can also get zinc from beans, nuts, whole grains, eggs, dairy products, and fortified breakfast cereals. Many dietary supplements, including multivitamin/mineral supplements, also contain zinc.
Q. How much zinc do I need and what happens if I don’t get enough?
A. Women need 8 milligrams (mg) of zinc per day and men need 11 mg; if you are pregnant or breastfeeding, you need a little more. Zinc deficiency can cause several problems, including loss of taste and smell, frequent infections, poor wound healing, and hair loss. Difficulties with thinking, reasoning, and memory can also occur in older adults. In infants and children, zinc deficiency can cause diarrhea, slow growth, and loss of appetite. It can also cause reproductive problems when these infants and children become adults.
Q. Are zinc deficiencies common in the United States?
A. Most people in the United States get enough zinc. But if you follow a vegetarian or vegan diet, you might fall short because most plant foods don't have as much zinc as animal foods. Others who might have trouble getting enough zinc include people with digestive disorders or who have had gastrointestinal surgery, those who are pregnant or breastfeeding, people who have alcohol use disorder, children with sickle cell disease, and some infants.
Your health care provider can help you determine if you are getting enough zinc and what to do if you are not. For example, they might recommend adding more foods that contain zinc into your diet or taking a dietary supplement.
Q. Does zinc help prevent or treat COVID-19?
A. Getting enough zinc is important for a healthy immune system, but taking zinc supplements hasn’t been shown to lower your risk of getting COVID-19 or help you recover quicker. For example, in one study, people who took zinc supplements regularly did not have a lower risk of getting COVID-19 than those who did not take zinc supplements. In another study, people with COVID-19 were split into four groups and took one of the following for 10 days: 50 mg zinc, 8,000 mg vitamin C, both supplements, or neither one. Zinc did not shorten the duration of symptoms.
Q. What about zinc and other illnesses?
A. Zinc might help with some illnesses in certain people. For example, lozenges that contain zinc might speed recovery from the common cold if you start taking them shortly after coming down with cold symptoms. In addition, zinc supplements help reduce the duration of diarrhea in children in developing countries. These children are often zinc deficient or otherwise malnourished. It’s not clear whether zinc supplements are helpful for diarrhea in children who get enough zinc, such as most children in the United States.
Q. Does getting too much zinc cause health problems?
A. Yes. Too much zinc can cause nausea, dizziness, headaches, upset stomach, vomiting, and loss of appetite. If you get too much zinc for a long time, it can also lower your immunity, reduce levels of HDL ("good") cholesterol, and reduce copper levels in your body.
Adults shouldn’t get more than 40 mg of zinc per day from foods and supplements, unless your health care provider recommends it.
Learn more about zinc on the Office of Dietary Supplements website.