Zinc is a mineral. It is called an "essential trace element" because very small amounts of zinc are necessary for human health. Since the human body does not store excess zinc, it must be consumed regularly as part of the diet. Common dietary sources of zinc include red meat, poultry, and fish. Zinc deficiency can cause short stature, reduced ability to taste food, and the inability of testes and ovaries to function properly.
Zinc is taken by mouth for the treatment and prevention of zinc deficiency and its consequences, including stunted growth and acute diarrhea in children, slow wound healing, and Wilson's disease.
It is also used for boosting the immune system, improving growth and heath in zinc deficient infants and children, for treating the common cold and recurrent ear infections, the flu, upper respiratory tract infections, preventing and treating lower respiratory infections, swine flu, ringing in the ears, and severe head injuries. It is also used for malaria and other diseases caused by parasites.
Some people use zinc for an eye disease called macular degeneration, for night blindness, and for cataracts. It is also used for asthma; diabetes and associated nerve damage; high blood pressure; AIDS/HIV, AIDS/HIV-related pregnancy complications; HIV-related diarrhea and AIDS diarrhea-wasting syndrome, AIDS-related infections, and high levels of bilirubin in blood (hyperbilirubinemia).
It is also taken by mouth anorexia nervosa, obsessive-compulsive disorder, depression, dementia, dry mouth, attention deficit-hyperactivity disorder (ADHD), blunted sense of taste (hypogeusia), hepatic encephalopathy, alcohol-related liver disease, Crohn's disease, ulcerative colitis, inflammatory bowel disease, canker sores, stomach ulcers, leg ulcers, and bed sores.
Some men take zinc by mouth for male fertility problems and enlarged prostate, as well as erectile dysfunction (ED).
Zinc is taken by mouth for osteoporosis, rheumatoid arthritis, psoriatic arthritis, warts, and muscle cramps in people with liver disease. It is also used for sickle cell disease, itching, rosacea, hair loss, psoriasis, eczema, acne, a blood disorder called thalassemia, Alzheimer's disease, Down syndrome, Hansen's disease, and cystic fibrosis.
It is also taken by mouth for cancer prevention, including esophageal cancer, colon and rectal cancer, stomach cancer, brain cancer, head and neck cancer recurrence, nasal and throat cancer recurrence, and non-Hodgkin's lymphoma. Zinc is used by mouth to prevent inflammation in the lining of the digestive tract, chemotherapy-related complications, anemia, pregnancy-related complications including iron deficiency, vitamin A deficiency (taken with vitamin A), arsenic poisoning, chronic obstructive pulmonary disease (COPD), clogged arteries, leukemia, burns, diaper rash, leprosy, and skin lesions caused by leishmania infection.
Some athletes use zinc by mouth for improving athletic performance and strength.
Zinc is also applied to the skin for treating acne, foot ulcers caused by diabetes, leg ulcers, diaper rash, warts, aging skin, brown patches on the face, herpes simplex infections, parasitic infections, and to speed wound healing. Zinc is also applied to the anus for people with problems controlling bowel movements.
Zinc citrate is used in toothpaste and mouthwash to prevent dental plaque formation and gingivitis. Zinc is also used in chew gum, candies, and mouth rinses to treat bad breath.
There is a zinc preparation that can be sprayed in the nostrils for treating the common cold.
Zinc sulfate is used in eye drop solutions to treat eye irritation.
Zinc is injected into the vein to improve nutrition in people recovering from burns.
Note that many zinc products also contain another metal called cadmium. This is because zinc and cadmium are chemically similar and often occur together in nature. Exposure to high levels of cadmium over a long time can lead to kidney failure. The concentration of cadmium in zinc-containing supplements can vary as much as 37-fold. Look for zinc-gluconate products. Zinc gluconate consistently contains the lowest cadmium levels.
How it works
Zinc is needed for the proper growth and maintenance of the human body. It is found in several systems and biological reactions, and it is needed for immune function, wound healing, blood clotting, thyroid function, and much more. Meats, seafood, dairy products, nuts, legumes, and whole grains offer relatively high levels of zinc.
Zinc deficiency is not uncommon worldwide, but is rare in the US. Symptoms include slowed growth, low insulin levels, loss of appetite, irritability, generalized hair loss, rough and dry skin, slow wound healing, poor sense of taste and smell, diarrhea, and nausea. Moderate zinc deficiency is associated with disorders of the intestine which interfere with food absorption (malabsorption syndromes), alcoholism, chronic kidney failure, and chronic debilitating diseases.
Zinc plays a key role in maintaining vision, and it is present in high concentrations in the eye. Zinc deficiency can alter vision, and severe deficiency can cause changes in the retina (the back of the eye where an image is focused).
Zinc might also have effects against viruses. It appears to lessen symptoms of the rhinovirus (common cold), but researchers can't yet explain exactly how this works. In addition, there is some evidence that zinc has some antiviral activity against the herpes virus.
Low zinc levels can be associated with male infertility, sickle cell disease, HIV, major depression, and type 2 diabetes, and can be fought by taking a zinc supplement.
Zinc deficiency might occur in people with severe diarrhea, conditions that make it hard for the bowel to absorb food, liver cirrhosis, and alcoholism. It may also occur after major surgery and during long-term use of tube feeding in the hospital. Taking zinc by mouth or giving zinc intravenously (by IV) helps to restore zinc levels in people who are zinc deficient. However, taking zinc supplements regularly is not recommended.
Zinc is LIKELY SAFE for most adults when applied to the skin, or when taken by mouth in amounts not larger than 40 mg daily. Routine zinc supplementation is not recommended without the advice of a healthcare professional. In some people, zinc might cause nausea, vomiting, diarrhea, metallic taste, kidney and stomach damage, and other side effects. Using zinc on broken skin may cause burning, stinging, itching, and tingling
Zinc is POSSIBLY SAFE when taking by mouth in doses greater than 40 mg daily. There is some concern that taking doses higher than 40 mg daily might decrease how much copper the body absorbs. Decreased copper absorption may cause anemia
Zinc is POSSIBLY UNSAFE when inhaled through the nose, as it might cause permanent loss of smell. In June 2009, the US Food and Drug Administration (FDA) advised consumers not to use certain zinc-containing nose sprays (Zicam) after receiving over 100 reports of loss of smell. The maker of these zinc-containing nose sprays has also received several hundred reports of loss of smell from people who had used the products. Avoid using nose sprays containing zinc
Taking high amounts of zinc is LIKELY UNSAFE. High doses above the recommended amounts might cause fever, coughing, stomach pain, fatigue, and many other problems.Taking more than 100 mg of supplemental zinc daily or taking supplemental zinc for 10 or more years doubles the risk of developing prostate cancer. There is also concern that taking large amounts of a multivitamin plus a separate zinc supplement increases the chance of dying from prostate cancer.Taking 450 mg or more of zinc daily can cause problems with blood iron. Single doses of 10-30 grams of zinc can be fatal.
Infants and children: Zinc isLIKELY SAFEwhen taken by mouth appropriately in the recommended amounts. Zinc isPOSSIBLY UNSAFEwhen used in high doses.
Pregnancy and breast-feeding: Zinc is LIKELY SAFE for most pregnant and breast-feeding women when used in the recommended daily amounts (RDA). However, zinc is POSSIBLY UNSAFE when used in high doses by breast-feeding women and LIKELY UNSAFE when used in high doses by pregnant women. Pregnant women over 18 should not take more than 40 mg of zinc per day; pregnant women age 14 to 18 should not take more than 34 mg per day. Breast-feeding women over 18 should not take more than 40 mg of zinc per day; breast-feeding women age 14 to 18 should not take more than 34 mg per day.
Alcoholism: Long-term, excessive alcohol drinking is linked to poor zinc absorption in the body.
Diabetes: Large doses of zinc can lower blood sugar in people with diabetes. People with diabetes should use zinc products cautiously.
Hemodialysis: People receiving hemodialysis treatments seem to be at risk for zinc deficiency and might require zinc supplements.
HIV (human immunodeficiency virus)/AIDS: Use zinc cautiously if you have HIV/AIDS. Zinc use has been linked to shorter survival time in people with HIV/AIDs.
Syndromes in which it is difficult for the body to absorb nutrients: People with malabsorption syndromes may be zinc deficient.
Rheumatoid arthritis (RA): People with RA absorb less zinc.
Cephalexin (Keflex) is an antibiotic used to treat infections. Zinc can reduce how much cephalexin (Keflex) the body absorbs if taken at the same time or 3 hours before cephalexin (Keflex). This might decrease how well cephalexin (Keflex) works for treating infections. But taking zinc 3 hours after taking cephalexin (Keflex) doesn't affect how much cephalexin (Keflex) the body absorbs. Therefore, zinc should be taken 3 hours after taking cephalexin (Keflex).Penicillamine
Penicillamine is used for Wilson's disease and rheumatoid arthritis. Zinc might decrease how much penicillamine your body absorbs and decrease the effectiveness of penicillamine. Take zinc and penicillamine at least 2 hours apart.
Zinc might decrease how much antibiotic the body absorbs. Taking zinc along with some antibiotics might decrease the effectiveness of some antibiotics. To avoid this interaction, take antibiotics at least 2 hours before or 4-6 hours after zinc supplements.Some of these antibiotics that might interact with zinc include ciprofloxacin (Cipro), levofloxacin (Levaquin), ofloxacin (Floxin), moxifloxacin (Avelox), gatifloxacin (Tequin) enoxacin (Penetrex), norfloxacin (Chibroxin, Noroxin), sparfloxacin (Zagam), trovafloxacin (Trovan), and grepafloxacin (Raxar).Zinc can attach to tetracyclines in the stomach. This decreases the amount of tetracyclines that can be absorbed. Taking zinc with tetracyclines might decrease the effectiveness of tetracyclines. To avoid this interaction, take tetracyclines 2 hours before or 4-6 hours after taking zinc supplements.Some tetracyclines include demeclocycline (Declomycin), minocycline (Minocin), and tetracycline (Achromycin, Sumycin).Atazanavir (Reyataz) is a drug used for HIV infection. Zinc decreases how much atazanavir (Reyataz) the body absorbs. But the body still absorbs enough atazanavir (Reyataz) for atazanvir to work for treating HIV. So this interaction is probably not a big concern.Cisplatin (Platinol-AQ)
Cisplatin (Platinol-AQ) is used to treat cancer. Taking zinc along with EDTA and cisplatin (Platinol-AQ) might inactivate cisplatin (Platinol-AQ) therapy. It is not known for sure, though, if the amount of interference caused by zinc is significant.Drugs used for HIV (Integrase inhibitors)
Taking zinc along with integrase inhibitors might decrease blood levels of integrase inhibitors. This might decrease their effectiveness. Talk to your healthcare provider if you are using integrase inhibitors and want to start taking zinc. Integrase inhibitors include dolutegravir (Tivicay), elvitegravir (Vitekta), and raltegravir (Isentress).Ritonavir (Norvir)
Zinc might decrease blood sugar in people with type 2 diabetes. Diabetes medications are also used to lower blood sugar. Taking zinc along with diabetes medications might cause your blood sugar to go too low. Monitor your blood sugar closely. The dose of your diabetes medication might need to be changed.Some medications used for diabetes include glimepiride (Amaryl), glyburide (DiaBeta, Glynase PresTab, Micronase), insulin, pioglitazone (Actos), rosiglitazone (Avandia), chlorpropamide (Diabinese), glipizide (Glucotrol), tolbutamide (Orinase), and others.Ritonavir (Norvir) is a drug used for HIV infection. Zinc can reduce how much ritonavir (Norvir) the body absorbs. But this doesn't seem to decrease the effects of ritonavir very much. So this interaction is probably not a big concern.