What to Know About Zinc Supplements

A nutritionist explains the benefits of zinc, and how to know if you need supplements.

You may have heard about zinc's role in supporting immunity, and you might wonder if you should be taking a zinc supplement. The National Institutes of Health (NIH) recommends that you get your zinc from food rather than a bottle, and there are important reasons behind that advice. Here's what to know about zinc supplements—along with some of zinc's additional benefits and top food sources.

Health Benefits Of Zinc

In addition to its role in supporting the immune system, zinc is required for the activity of more than 300 enzymes that aid with a range of important aspects of your health—healthy digestion, nerve function, and metabolism, according to the NIH.

Zinc also supports brain health. A 2017 review, published in the International Journal of Molecular Sciences, concluded that changes in zinc balance in the brain may affect conditions that include age-related cognitive decline, depression, and Alzheimer's disease.

Another of zinc's major roles is helping the body heal. Zinc is required for cell membrane repair, cell growth, and the maintenance of healthy skin. Zinc-dependent proteins play fundamental roles within cells, including in DNA repair. For these reasons, a zinc deficiency can lead to skin problems and impaired wound healing, according to a 2018 review in the journal Nutrients.

Too little zinc can negatively impact your senses and appetite. According to a 2016 review article in the journal The Consultant Pharmacist, 35% to 45% of adults 60 and older had zinc intakes below the estimated average requirement. Some of the side effects tied to zinc deficiency involve diminished taste and smell, and a poor appetite.

Studies have shown that zinc deficiency increases oxidative stress, which is an imbalance between the production of cell-damaging free radicals and the body's ability to counter their harmful effects. A 2014 research study published in Frontiers in Nutrition said that zinc reduces blood markers for inflammation, a known trigger of premature aging and chronic disease.

Zinc In Your Diet

Zinc is readily found in both animal and plant-based foods. The NIH says that top animal sources include oysters (which ranks as the number one source), beef, crab, lobster, pork, and yogurt. Plant sources include vegetarian baked beans, pumpkin seeds, sesame seeds, cashews, chickpeas, lentils, quinoa, oatmeal, and zinc-fortified plant foods, such as cereal.

The amount you need daily can easily be obtained through a normal, balanced diet, according to the NIH.

The recommended dietary allowances for zinc are:

  • 11 milligrams (mg) per day for men ages 14 and up
  • 8 mg per day for women 19 and over, and 9 mg per day for females ages 14-18
  • 11 mg per day for people who are pregnant and 12 mg per day for people who are lactating
  • 8 mg per day for children ages 9-13
  • 5 mg per day for children ages 4-8
  • 3 mg per day for children ages 7 months to age 3
  • 2 mg per day for babies up to age 6 months

A three-ounce beef patty provides 5.3 mg. One cup of vegetarian baked beans provides 5.8 mg.

Even vegetarians can eat enough zinc. According to the Academy of Nutrition and Dietetics, adult vegetarians have zinc intakes that are within the normal range. In addition, an adult's body can adapt to a vegetarian diet in ways that help optimize zinc status, including increased absorption and retention of zinc.

Obtaining your zinc through food can also broaden your overall nutrient intake since zinc-containing foods offer other important nutrients, which may include protein, fiber, other vitamins and minerals, and health-protective antioxidants. Getting your zinc solely through your diet also reduces the potential risks tied to taking in too much zinc in supplement form.

Zinc Deficiency

According to the NIH, routine zinc supplementation is not recommended without the advice of a health care professional.

The NIH says that some risk factors for zinc deficiency include sickle cell disease, gastrointestinal disease, or a history of bariatric surgery (a type of weight loss surgery). The agency also says that a vegan diet that's heavy in legumes and whole grains could be a risk factor since these foods contain components that inhibit the body's absorption of zinc. if you are at risk, your healthcare provider may ask about whether you have symptoms of zinc deficiency or may order testing for you.

Zinc Supplements

If a healthcare provider recommends zinc supplements, you can work with them to select the best form and dose for you. And since zinc can interact with certain medications, medical conditions, and other supplements, you might need to adjust your dose based on medical conditions or medications that you take.

There are numerous types of zinc supplements, including zinc gluconate, picolinate, acetate, and citrate, and various forms, such as lozenges, capsules, and drops.

Some considerations per the NIH:

  • zinc should not be inhaled through the nose, as this may cause permanent loss of smell.
  • zinc may decrease how much antibiotic the body absorbs from the gut.
  • supplemental zinc can reduce blood sugar in people with type 2 diabetes, which may impact medication needs and blood sugar control.
  • high-dose calcium supplements may decrease zinc absorption.
  • taking zinc sulfate with black coffee has been shown to reduce the mineral's absorption by half.

Risks of Excess Zinc

The Tolerable Upper Intake Level (UL) for zinc, which includes both foods and supplements combined, is 40 mg per day for all adults 19 and over, according to the NIH. A long-term intake above this amount increases the risk of adverse health effects unless supplemental zinc is prescribed and monitored by a physician for a specific medical condition.

Per the NIH, too much zinc in supplement form can trigger adverse effects that include:

  • nausea
  • vomiting
  • loss of appetite
  • abdominal cramps
  • diarrhea
  • headaches
  • altered copper and iron function
  • reduced immunity
  • lower blood levels of "good" HDL cholesterol

So be sure to keep in mind that more zinc isn't better. If your doctor or registered dietitian has recommended a zinc supplement for any reason, ask about the dosage, form, frequency, and length of use, and when and how to take it.

Zinc Lozenges For Colds

Due to zinc's impact on immunity, many people turn to the mineral for the short-term to combat colds. But the results of research on zinc's effect on the common cold have been mixed.

A 2017 study published in Open Forum Infectious Diseases found that patients who had the common cold and who were given zinc lozenges recovered faster than those who did not take zinc. After five days, 70% of the zinc patients had recovered compared with 27% of the placebo patients.

However, a 2020 study published in the journal Pharmacology and Therapeutics found that zinc acetate lozenges had no impact on the common cold recovery rate compared to a placebo when used for five days after the first symptoms began. Reported side effects include a bad taste in the mouth and nausea.

If you do choose to try zinc when you feel a cold coming on, seek professional guidance on the form, dose, and length of use.

A Healthy Zinc Balance

To best benefit from zinc without going overboard, focus on food sources. If you're an omnivore, aim for a variety of plant and animal foods. If you're plant-based, zero in on top plant sources and be sure to incorporate them often.

If you're concerned about not getting enough zinc from your regular diet due to health issues, food preferences, or dietary restrictions, talk to a healthcare provider or dietitian for guidance and discuss whether zinc supplements might be appropriate for you. Zinc is one of the most important nutrients for optimal wellness, and striking the right balance is vital for reaping its benefits.

Cynthia Sass, MPH, RD, is Health's contributing nutrition editor, a New York Times best-selling author, and a private practice performance nutritionist who has consulted for five professional sports teams.

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