What Is Zinc?
Medically reviewed by Jamie Johnson, RDN
People only need a small amount of zinc, but it plays an important role in the body. Zinc is integral in DNA creation, immune support, cell growth, tissue healing, protein building, and the senses. It is necessary for healthy growth during childhood, adolescence, and pregnancy.
A zinc deficiency can cause problems with wound healing, slow growth, loss of taste and smell, and cognitive problems. If severe, it can even cause death. In most industrialized countries, zinc deficiencies are fairly rare, although they can occur in certain populations.
Read on to find out more information about why someone might need zinc supplementation, foods to eat to get enough zinc, and how to safely supplement with it.
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Explainer
Dietary supplements are not regulated the way drugs are in the United States, which means the Food and Drug Administration (FDA) does not approve them for safety and effectiveness before the products are marketed. When possible, choose a supplement tested by a trusted third party, like USP, ConsumerLabs, or NSF.
Remember that third-party testing does not guarantee safety or effectiveness. It’s important, then, to talk with your healthcare provider about any supplements you plan to take, and ask about any potential interactions with other supplements or medications.
Supplement Facts
Active ingredient: Zinc
Alternate names: Zinc sulfate, zinc picolinate, zinc glycerate, zinc citrate, zinc acetate, zinc monomethionine
Legal status: Over the counter
Suggested dose: Supplements are generally 30 to 50 milligrams (mg) each. Follow instructions on the label or per your healthcare provider's instructions.
Safety considerations: Before taking supplements, check with your healthcare provider to see if there are potential interactions with any other supplements or medications you are taking and if it is safe and appropriate for you to take zinc.
Benefits of Zinc
Supplement use is unique to each person and should be vetted by a healthcare professional, such as a registered dietitian, pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease. Ask your healthcare provider before starting to use any supplement whether it is safe and appropriate for you.
Most people get enough zinc by eating a healthy and varied diet and by taking a multivitamin. The recommended daily allowance for adults is between 8 mg and 11 mg, and it can vary if you are pregnant or lactating.
For people in industrialized countries, the likelihood of being significantly deficient in zinc is rare. People who may have lowered zinc levels include older people and those with alcohol use disorder, anorexia, or who are on severely restricted diets.
Those with conditions with malabsorption problems, like Crohn’s disease or celiac disease, as well as those who’ve had bariatric (weight-loss) surgery, may also have zinc deficiencies.
Zinc supplementation may be suggested to help with:
Acne: People with acne often have lowered serum zinc levels, and both oral and topical zinc have been found to reduce the prevalence of inflammatory papules, both when used as monotherapy and as a supplemental therapy.
Age-related macular degeneration (AMD): AMD is an eye condition affecting a part of the light-sensitive retina. Zinc is included in the Age-Related Eye Disease Studies (AREDS and AREDS2) formulas that contain other vitamins and minerals. These supplements have been found beneficial for people with intermediate or late AMD in clinical trials, but they don't prevent AMD or help in early AMD.
Attention deficit hyperactivity disorder (ADHD): Studies of zinc levels in people with ADHD have been inconsistent. A meta-analysis found that those living with ADHD might be more likely to have lower zinc levels, and therefore screening for zinc deficiency—and then supplementing—might be useful.
Bone health: Zinc plays a key role in bone development and bone repair. Researchers suspect zinc may also work to prevent osteoporosis. However, the optimal dose is unclear, and more studies are needed.
Colds (as lozenges): Zinc lozenges may help prevent cold symptoms or shorten the length of a cold, but the studies have had a high risk of bias (being sponsored by drug companies), had small numbers of participants, or used different methods and are hard to compare.
Preventing chronic conditions: Zinc is an antioxidant that helps combat oxidative stress. Studies show zinc lowers markers of systemic inflammation. Inflammation and oxidative stress are associated with several chronic conditions, including arthritis, heart disease, kidney disease, and neurological conditions like Alzheimer’s, Parkinson’s, and multiple sclerosis. Scientists suspect zinc supplements may help to prevent chronic diseases, though more research is needed.
Sickle cell disease: Sickle cell disease is an inherited condition affecting the red blood cells. Many people with sickle cell disease are deficient in zinc, which can cause lowered immunity and increased risk of infection. Supplementing with zinc can lower both disease-associated morbidity as well as infections.
Type 2 diabetes: Zinc may help lower blood sugar and cholesterol in people with type 2 diabetes. Research ties zinc supplements to reduced levels of fasting glucose, post-meal blood sugar, triglyceride, total cholesterol, and LDL cholesterol. Zinc deficiency may also play a role in the development of type 2 diabetes.
If you have any of these conditions, talk with your healthcare provider. You may have to take high doses of the supplement for a small period of time, under the supervision of a professional. Many studies of zinc treatments for different conditions have proven not to be clinically significant, or the dosage of zinc would be so high that it’s dangerous.
What Are the Side Effects of Zinc?
Zinc supplements can cause various side effects. They may be common or severe, depending on how much zinc you take and other factors.
Common Side Effects
Most people taking zinc supplements have little to no side effects, although like any vitamin/mineral supplement, zinc can cause slight upset stomach if taken without food. Take zinc with water or juice, and not at the same time as any iron or calcium supplements.
A good time to take the supplement is right after breakfast, depending on when you take other supplements.
Severe Side Effects
Severe side effects can happen if you take too much zinc, and can include:
Nausea and vomiting
Loss of appetite
Stomach pain or cramping
Diarrhea
Headaches
Zinc nasal sprays or nasal gels have been associated with a loss of sense of smell for some people.
Precautions
You don’t need a lot of zinc to be healthy. Zinc is what is known as a trace mineral. Most people get what they need from dietary sources. Because of the potential for significant adverse effects and interactions with medications or other supplements, it should be used under the supervision of your healthcare provider.
Dosage: How Much Zinc Should I Take?
People of different ages need different amounts of zinc, and most people get enough from their diet and multivitamins. People who are pregnant and/or breastfeeding need more zinc because of their bodily demands and needs.
For children ages birth to 13, recommended dietary allowances (RDAs) range from 2 mg to 8 mg, depending on age. Teenagers age 14 to 18 need 11 mg for males, 9 mg for females, 12 mg if pregnant, and 13 mg if breastfeeding.
Adult males 19 and older should get 11 mg daily; adult females 19 and older, 8 mg;people who are pregnant or breastfeeding, 11 mg and 12 mg, respectively.
(Note that Verywell Health prefers to use inclusive terminology. But when citing health authorities or research, the terms for sex or gender from those sources are used.)
A regular multivitamin is generally enough for most adults, but children, pregnant and nursing people, and older adults should see a healthcare provider to assess what kind of supplementation they need.
Eating a healthy and varied diet and taking a daily multivitamin usually provides all the zinc you need, without extra zinc supplementation. If supplementation is needed, it is typically done over limited periods of time, taking plenty of breaks. Your healthcare provider can talk with you more about whether extra zinc supplementation is necessary and the length of time you should be on it.
If you are a vegetarian or vegan, talk with your healthcare provider about your diet to see whether you are getting all the nutrients you need, including zinc. A prenatal vitamin may be enough for pregnant and nursing people.
But if a child or older adult is deficient, they may need specific doses of zinc supplementation under the supervision of a healthcare provider. Do not give zinc supplements to a child without the instructions of a healthcare provider.
What Happens if I Take Too Much Zinc?
There have been no reports of getting too much zinc through diet, but there is a danger of zinc toxicity from supplements. To avoid toxicity, be aware of the proper dosage, and be mindful of the suggested upper limit of the supplement.
For adults, the upper tolerable limit of daily intake of zinc, which includes from both food and supplements, is 40 mg. Too much zinc can cause side effects such as:
Nausea and/or vomiting
Headache
Dizziness
Loss of appetite
It’s not good to take zinc supplements for long periods of time, especially every day. If you take too much zinc for prolonged periods of time, you can lower your own natural immunity, impair your body’s ability to absorb magnesium, and lower your high-density lipoprotein (HDL) cholesterol, considered the “good” cholesterol.
Chronic and excessive zinc supplementation can cause copper deficiency and neurological problems as well.
An ongoing prospective cohort study (one that follows participants over many years) of U.S. males found those who took high levels of supplemental zinc (more than 75 milligrams per day) were at higher risk for prostate cancer, and those who took supplemental zinc for more than 15 years were also at higher risk for lethal and more aggressive prostate cancer.
If you think you’ve taken too much zinc, contact the poison control hotline or go to the emergency room.
Interactions
Even though they're not prescriptions, supplements can interact with food, medications, or other supplements. Sometimes this can be dangerous and cause serious adverse effects. With zinc, interactions can include:
Various antibiotics can lower zinc levels and interfere with your body’s absorption of zinc; take the antibiotic two hours before the supplement, or four to six hours after the supplement.
The drug Cuprimine (penicillamine) for rheumatoid arthritis and Wilson's disease ( a condition in which there are high amounts of copper in the body) can be modified by zinc supplements, so take the zinc and the medication at least one hour apart.
Certain diuretics (water pills) increase the volume of zinc lost in the urine, lowering zinc levels in the body.
This is not a complete list of interactions; before taking zinc supplements, ask a healthcare provider if it is safe for you to take them.
It’s very important to read the ingredient list and nutrition facts panel of a supplement so you know what is in it. Please review this information with a healthcare provider to discuss any possible interactions with foods or any other medications or supplements that you take.
How to Store Zinc
As with many vitamin and mineral supplements, light, heat, and humidity can all impact the quality and integrity of zinc supplements. Store your supplements in a cool, dark, and dry place. Do not store in the refrigerator or leave it in the bathroom, where there is too much moisture.
Keep zinc supplements away from direct sunlight. Discard the supplements as indicated on the packaging.
Similar Supplements
Zinc is often used to supplement or boost the immune system or improve skin conditions, but other supplements do that, as well. Similar supplements can include, but are not limited to:
Vitamin A (retinol)
Vitamin C (ascorbic acid)
Alpha-linolenic acid (ALA)
Vitamin B3 (niacin)
If you are taking more than one supplement, ask your healthcare provider if they should be taken alongside each other.
Sources of Zinc and What to Look For
The best way to get enough zinc is through your diet. If this isn’t possible, fortified foods and supplements can be added. For vegetarians and vegans, legumes (peas, beans, lentils) and whole grains can inhibit the absorption of zinc, so supplementation might be necessary.
Food Sources of Zinc
Foods that contain zinc include:
Oysters
Meat
Fish
Chicken
Some seafood, like crab and lobster
Fortified cereals
Foods that have some zinc, but not as much, include beans, nuts, whole grains, eggs, and dairy products.
Zinc Supplements
Nearly all of the general multivitamin and mineral dietary supplements have zinc in them. You can also get an isolated zinc supplement or a supplement in which zinc is combined with something like calcium.
There are different forms of zinc in supplements, but one has not been shown to be better than the others. Sometimes zinc is also in denture adhesives or homeopathic remedies.
Summary
Zinc is an important mineral for good health, growth, immune support, and overall functioning. While most people get all the zinc they need from a healthy and varied diet and a multivitamin, some people may need to supplement a bit more.
Because the body only needs a small amount of zinc, it can be easy to take too much and experience negative side effects. Talk with a healthcare provider about whether supplementation is necessary, and the possibility of any adverse interactions with your existing medication and supplement consumption.
Read the original article on Verywell Health.
