If you feel the sniffles coming on, you may have heard that taking zinc for a cold can help get your body back to normal faster. That may be true, but zinc is responsible for so much more in the grand scheme of your health.
Zinc is an essential micronutrient that's vital to many aspects of your health. Although whole-food sources are always the best way to get your nutrients, you may benefit from a zinc supplement if you have a deficiency.
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Many forms of zinc supplements are available, so it's helpful to understand your choices when deciding which is the best form of zinc for you.
Choose a chelated form of zinc supplement for the best bioavailability in your body.
Benefits of Zinc
Zinc is an important element required for the chemical reactions of over 300 enzymes, according to Oregon State University (OSU).
1. Supports a Strong Immune System
Zinc is necessary for the proper functioning of your immune system. That's why zinc is most commonly used as a supplement to help improve immunity, William Li, MD, president and medical director of the Angiogenesis Foundation and author of Eat to Beat Disease, tells LIVESTRONG.com.
2. May Shorten the Life of a Cold
As we mentioned, taking zinc at the first sign of a cold (within the first 24 hours) could reduce both how long the cold lasts and the severity of symptoms, according to a November 2011 meta-analysis in The Journal of Family Practice.
3. Supports Eye Health
Specifically, zinc supplements might help slow the progression of age-related macular degeneration (AMD), Dr. Li says.
Malnutrition in older adults is a concern and often a cause for zinc deficiency. As such, research indicates that zinc supplementation may be able to have positive effects on AMD, according to a July 2020 paper in the International Journal of Molecular Sciences.
4. Aids in Wound Healing
Zinc is essential in the healing process. People who have skin ulcers or low levels of zinc may benefit from supplementing with zinc, per the Mayo Clinic.
How Much Zinc Do You Need?
For safety, and to prevent deficiency, the recommended dietary allowance (RDA) for zinc is based on age and sex assigned at birth.
These values include the total zinc intake from food sources, including fortified foods, forms of supplements and multivitamins, medications and household items containing zinc.
Recommended Daily Allowance for Zinc
Birth to 6 months
7 to 12 months
One to 3 years
4 to 8 years
9 to 13 years
14 to 18 years
Symptoms of Zinc Deficiency
"True zinc deficiency is rarely seen," Dr. Li points out, "but it is possible to determine if zinc levels are unusually low if a person has symptoms."
Symptoms of a zinc deficiency that might prompt a call to your doctor include:
- Hair loss
- Poor wound healing
- Recurrent viral illness
- Loss of appetite
- Delayed sexual maturation or impotence
- Eye and skin lesions
- Weight loss
- Taste abnormalities
- Mental lethargy
- Growth retardation in children
Types of Zinc
Zinc supplements are available in capsule, tablet, time-released, powdered, syrup, nasal spray and lozenge forms. Zinc is often included as part of a multivitamin formula.
Best Form of Zinc: Chelated
Your body does not naturally digest zinc easily. To make it more bioavailable, zinc can be chelated, which means it is bonded to another compound to make it absorbable.
Chelated zinc is also the most studied form of zinc in humans, although the National Institutes of Health (NIH) indicates that it is not entirely clear which form is better than another.
Dr. Li recommends the following forms of chelated zinc, as they're generally well absorbed:
- Zinc gluconate
- Zinc citrate
- Zinc picolinate
Other common forms of chelated zinc include:
- Zinc orotate
- Zinc acetate
Zinc acetate may be your best bet when looking for a lozenge to help your common cold symptoms. Findings of a 2017 study in Open Forum Infectious Diseases recommended consuming zinc acetate lozenges within 24 hours of the onset of a cold for a three-fold increase in the rate of recovery.
Try These Zinc Supplements
Inorganic Zinc Supplements
Inorganic zinc may not be as effective or useable by your body as chelated zinc sources.
Some forms of inorganic zinc are:
- Zinc sulfate
- Zinc oxide
Dr. Li adds that zinc sulfate is the type that is least absorbed by the body.
Zinc oxide, when given as an oral supplement, was found to have a significantly lower level of bioavailability than zinc citrate or zinc gluconate in a February 2014 study in the The Journal of Nutrition. You might be more familiar with zinc oxide as a topical agent, used in sunscreens or for treatment of skin conditions.
Do You Need a Supplement?
If you cannot get an adequate amount of zinc from your diet or if you have a medical condition, you may need to take a zinc supplement. Some reasons you may be at risk for low levels of zinc in your body include the following, according to OSU:
- Vegetarians may need more than the RDA for zinc due to low bioavailability of zinc from plant-based foods.
- Medical or digestive disorders that inhibit the absorption of nutrients, such as Crohn's, colitis, chronic diarrhea or IBS
- Chronic liver disease or sickle cell anemia
- Alcohol abuse
Safety and Side Effects
Dr. Li gives some pointers of the safety and side effects of zinc supplementation: "Zinc is an overall safe supplement to take at usual doses, which is 40 mg or less per day. Some studies suggest high doses (100 mg or higher) may be associated with an increased risk of developing advanced prostate cancer compared to men who did not take zinc."
Intake of zinc above the recommended upper level could result from a combination of dietary supplements, multivitamins, food and food additives, ingestion of zinc-containing medications or household products.
"More common side effects of zinc supplementation are a metallic taste in the mouth, nausea and GI upset," adds Dr. Li.
Adverse health effects from zinc toxicity can occur suddenly or over a period of time, such as taking more than the recommended amount of lozenges.
Zinc toxicity symptoms may include:
- Loss of appetite
- Stomach pains
If you are taking zinc supplements, use caution if you are on antibiotics, penicillamine or thiazide diuretics, according to the Mayo Clinic. Ensure you always have a conversation with your doctor about the safety of your supplements if you are taking any medication.
Food Sources of Zinc
If you eat a balanced diet, you should be able to get your daily zinc needs from food. Getting your zinc from food also provides fiber and energy in the form of fats, proteins and carbohydrates, and is a balanced source of minerals and vitamins.
A wide variety of foods provide zinc, with oysters containing more zinc per serving than any other food, according to the NIH. Oysters supply 74 milligrams per 3-ounce serving, which is 494 percent of your RDA. Other good food sources of zinc are:
- Meat: beef, chicken, pork
- Fish and seafood: salmon, crab, lobster
- Fortified foods: breakfast cereals, snack bars
- Beans and legumes: baked beans, kidney beans, chickpeas, green peas
- Dairy products: cheese, yogurt, milk
- Nuts: almonds, cashews
- Oregon State University: Linus Pauling Institute: "Zinc"
- National Institutes of Health: "Zinc"
- Mayo Clinic: "Zinc"
- The Journal of Nutrition: "Zinc Absorption by Young Adults From Supplemental Zinc Citrate Is Comparable With That From Zinc Gluconate and Higher Than From Zinc Oxide."
- Open Forum Infectious Diseases: "Zinc Acetate Lozenges May Improve the Recovery Rate of Common Cold Patients: An Individual Patient Data Meta-Analysis"
- NIH: "Zinc Factsheet for Consumers"
- International Journal of Molecular Sciences: "Zinc and Autophagy in Age-Related Macular Degeneration"
- The Journal of Family Practice: "Zinc for the common cold—not if, but when"