Zinc

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 does it work?

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.
Diarrhea.
An inherited disorder called Wilson's disease.
Acne.
An inherited disorder that affects zinc uptake (acrodermatitis enteropathica).
Age-related vision loss (age-related macular degeneration).
Anorexia.
Attention deficit-hyperactivity disorder (ADHD).
Burns.
Tumors in the rectum and colon.
Common cold.
Depression.
Foot ulcers due to diabetes.
Diaper rash.
Gingivitis.
Bad breath.
Herpes simplex virus.
Taste disorder (hypogeusia).
Skin lesions (Leishmania lesions).
Leprosy.
Weak bones (osteoporosis).
Peptic ulcers.
Pneumonia.
Complications during pregnancy.
Bed sores.
Food poisoning (shigellosis).
Sickle cell disease.
Leg ulcers.
Vitamin A deficiency.
Warts.

Adults

By Mouth:

General: Recommended Dietary Allowance (RDA) quantities of zinc have been established for boys and men age 14 and older, 11 mg/day; women 19 and older, 8 mg/day; pregnant women 14 to 18, 13 mg/day; pregnant women 19 and older, 11 mg/day; lactating women 14 to 18, 14 mg/day; lactating women 19 and older, 12 mg/day. Tolerable Upper Intake Levels (UL) of zinc for people who are not receiving zinc under medical supervision: adults 19 years and older (including pregnancy and lactation), 40 mg/day. The typical North American male consumes about 13 mg/day of dietary zinc; women consume approximately 9 mg/day. Different salt forms provide different amounts of elemental zinc. Zinc sulfate contains 23% elemental zinc; 220 mg zinc sulfate contains 50 mg zinc. Zinc gluconate contains 14.3% elemental zinc; 10 mg zinc gluconate contains 1.43 mg zinc.

For zinc deficiency: In people with mild zinc deficiency, recommendations suggest taking two to three times the recommended dietary allowance (RDA) of zinc for 6 months. In people with moderate to severe deficiency, recommendations suggest taking four to five times the RDA for 6 months.

For diarrhea: To prevent diarrhea in infants, pregnant women have used 15 mg of zinc, with or without 60 mg of iron and 250 mcg of folic acid, starting 10-24 weeks into pregnancy through one month after giving birth.

For treating Wilson's disease: Zinc acetate (Galzin in the U.S.; Wilzin in Europe) is an FDA-approved drug for treating Wilson's disease. The recommended dose, which contains 25-50 mg of zinc, is to be taken three to five times daily.

For treating acne: 30-150 mg elemental zinc daily has been used.

For an inherited disorder that affects zinc uptake (acrodermatitis enteropathica): Taking 2-3 mg/kg of elemental zinc daily for a lifetime is recommended for treating an inherited disorder that affects zinc uptake.

For age-related vision loss (age-related macular degeneration): A combination of 80 mg of elemental zinc, 2 mg of copper, 500 mg of vitamin C, 400 IU of vitamin E, and 15 mg of beta-carotene taken daily for 5 years has been used in people with advanced age-related vision loss.

For the eating disorder anorexia nervosa: 14-50 mg of elemental zinc has been used daily.

For tumors in the colon and rectum: A combination supplement containing 200 mcg of selenium, 30 mg of zinc, 2 mg of vitamin A, 180 mg of vitamin C, and 30 mg of vitamin E has been taken daily for up to 5 years.

For treating the common cold: One zinc gluconate or acetate lozenge, providing 4.5-24 mg elemental zinc, dissolved in the mouth every two hours while awake when cold symptoms are present.

For depression: 25 mg of elemental zinc has been used daily for 12 weeks along with antidepressant medications.

For taste disorder (hypogeusia): 140-450 mg of zinc gluconate has been taken in up to three divided doses daily for up to 4 months. Also, 25 mg of elemental zinc taken daily for 6 weeks has been used. A zinc-containing product called polaprezinc (Promac, Zeria Pharmaceutical Co., Ltd) has also been used.

For skin lesions (leishmania lesions): 2.5-10 mg/kg of zinc sulfate has been taken in three divided doses daily for 45 days.

For muscle cramps: 220 mg of zinc sulfate has been taken twice daily for 12 weeks.

For osteoporosis: A combination of 15 mg of zinc combined with 5 mg of manganese, 1000 mg of calcium, and 2.5 mg of copper has been used.

For stomach ulcers: 300-900 mg of zinc acexamate has been taken in one to three divided doses daily for up to one year. Also, 220 mg of zinc sulfate has been taken three times daily for 3-6 weeks.

For pregnancy-related complications: 25 mg of zinc has been taken daily in combination with vitamin A for 3 weeks to restore vision in pregnant women with night blindness.

For bed sores: A standard hospital diet plus 9 grams of arginine, 500 mg of vitamin C, and 30 mg of zinc has been used daily for 3 weeks.

For sickle cell disease: 220 mg of zinc sulfate three times daily has been used. Also, 50-75 mg of elemental zinc taken daily in up to two divided doses for 2-3 years has been used.

For leg ulcers: 220 mg of zinc sulfate taken three times daily has been used along with ulcer dressings.

For warts: 400-600 mg of zinc sulfate daily for 2-3 months.

Applied to the Skin:

For acne vulgaris: Zinc acetate 1.2% with erythromycin 4% as a lotion applied twice daily.

For foot ulcers due to diabetes: A zinc hyaluronate gel has been applied once daily to ulcers until healed.

For gingivitis: Toothpaste containing 0.2% to 2% zinc citrate alone or with sodium monofluorophosphate or 0.2% triclosan, have been used at least two times daily for up to 7 months. A mouth rinse containing 0.4% zinc sulfate and 0.15% triclosan has also been used.

For bad breath: Two zinc-containing mouth rinses called Halita and Meridol have been used as single doses or twice daily for 7 days. Candies and chewing gums containing zinc have also been used.

For herpes simplex infections: Zinc sulfate 0.025% to 0.25% applied 8 to 10 times daily or zinc oxide 0.3% with glycine applied every 2 hours while awake has been used. Specific products containing zinc (Virudermin Gel, Robugen GmbH, SuperLysine Plus +, Quantum Health, Inc., Herpigon) have also been used.

For bed sores: A zinc oxide paste has applied daily along with standard care for 8-12 weeks.

For leg ulcers: A paste containing zinc oxide 25% has been applied as a dressing once daily for the first 14 days of treatment and every third day thereafter for 8 weeks.

For warts: A zinc oxide 20% ointment has been applied twice daily for 3 months or until cured. Zinc sulfate 5% to 10% has been applied to the skin three times daily for 4 weeks.

Children

By Mouth:

General: The Institute of Medicine has established Adequate Intake (AI) levels of zinc for infants birth to 6 months is 2 mg/day. For older infants and children, Recommended Dietary Allowance (RDA) quantities of zinc have been established: infants and children 7 months to 3 years, 3 mg/day; 4 to 8 years, 5 mg/day; 9 to 13 years, 8 mg/day; girls 14 to 18 years, 9 mg/day. The Tolerable Upper Intake Levels (UL) of zinc for people who are not receiving zinc under medical supervision: Infants birth to 6 months, 4 mg/day; 7 to 12 months, 5 mg/day; children 1 to 3 years, 7 mg/day; 4 to 8 years, 12 mg/day; 9 to 13 years, 23 mg/day; and 14 to 18 years (including pregnancy and lactation), 34 mg/day.

For an inherited disorder that affects zinc uptake (acrodermatitis enteropathica): Taking 2-3 mg/kg of elemental zinc daily for a lifetime is recommended for treating an inherited disorder that affects zinc uptake.

For the eating disorder anorexia nervosa: 14-50 mg of elemental zinc has been used daily.

For treating attention deficit-hyperactivity disorder (ADHD): 55-150 mg of zinc sulfate containing 15-40 mg of elemental zinc has been taken daily for 6-12 weeks.

For treating the common cold: One lozenge containing 10-23 mg of zinc gluconate, dissolved in the mouth every two hours has been used for up to 10 days. A syrup containing 15 mg of zinc has also been used twice daily for up to 10 days.

For diaper rash: 10 mg of zinc has been taken daily from the first or second day of life until 4 months of age.
For diarrhea: 10-40 mg of elemental zinc has been taken daily for 7-15 days to treat diarrhea in malnourished or zinc-deficient children.

For skin lesions (leishmania lesions): 2.5-10 mg/kg of zinc sulfate taken in three divided doses daily has been used for 45 days.

For pneumonia: In developing countries, 10-70 mg of elemental zinc has been taken daily in undernourished children aged 3 months to 5 years. Also, 2 mg/kg of zinc sulfate has been taken daily in two divided doses for 5 days.

For food poisoning (shigellosis): Multivitamin syrup containing 20 mg of elemental zinc has been used in two divided doses daily for 2 weeks.

For sickle cell disease: 10 mg of elemental zinc has been taken daily for one year in children 4-10 years of age. Also, 15 mg of elemental zinc has been taken twice daily for one year in boys aged 14-18 years.

For leg ulcers: 220 mg of zinc sulfate has been used three times daily along with ulcer dressings.

For vitamin A deficiency: 20 mg of elemental zinc has been taken daily for 14 days, with 200,000 IU of vitamin A on day 14, has been used in children 1-3 years of age.

Applied to the Skin:

For acne: Zinc acetate 1.2% with erythromycin 4% as a lotion applied twice daily for 12-40 weeks.

For diaper rash: A zinc oxide paste containing allantoin 0.5%, cod liver oil 17%, and zinc oxide 47% has been used for 5 days.

Zinc is 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 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 is SAFE when taken by mouth appropriately in the recommended amounts. Zinc is POSSIBLY UNSAFE when used in high doses.

Pregnancy and breast-feeding: Zinc is 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.