Zinc Supplements: What to Know if You're Thinking of Taking Them
You may be familiar with zinc’s role in supporting immunity, and that connection might leave you wondering if you should be taking a zinc supplement. As a registered dietitian, I recommend 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 to rely on.
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 healthy digestion, nerve function, and metabolism.
Zinc also supports brain health. Compared to other organs in the body, zinc concentration is highest in the brain. A 2017 study, published in the International Journal of Molecular Sciences, concluded that while there are many unknowns, 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.
Too little zinc can negatively impact your senses and appetite. According to one recent study, 35% to 45% of adults 60 and older had zinc intakes below the estimated average requirement. One set of side effects tied to zinc deficiency involves diminished taste and smell, plus poor appetite. If you’ve ever lost these senses due to illness, you’re aware of how much they affect the appeal of food. In healthy adults, zinc plays a role in maintaining these functions.
Finally, several studies have shown that zinc deficiency increases oxidative stress, which is essentially an imbalance between the production of cell-damaging free radicals and the body's ability to counter their harmful effects. Zinc has also been shown to reduce blood markers for inflammation, a known trigger of premature aging and chronic disease.
Best zinc food sources
Unlike some nutrients that are more difficult to obtain from food alone, such as vitamin D, zinc is readily found in both animal and plant-based foods. 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. For example, the recommended dietary allowances for zinc are 11 mg per day for men ages 19 and up, and 8 mg for women 19 and over. The requirements for women who are pregnant or lactating are 11 mg and 12 mg respectively. A three-ounce beef patty provides 5.3 mg. One cup of vegetarian baked beans provides 5.8 mg.
In other words, even vegetarians can eat enough zinc. According to the Academy of Nutrition and Dietetics, studies show that adult vegetarians (compared to non-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 broadens 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. It also negates the potential risks tied to taking in too much zinc in supplement form.
Zinc supplements: what to know
There are numerous types of zinc supplements, including zinc gluconate, picolinate, acetate, and citrate, and various forms, such as lozenges, capsules, and drops.
According to the National Institutes of Health, routine zinc supplementation is not recommended without the advice of a health care professional. In addition to choosing the best form and dose (more on this below), zinc can interact with certain medications, medical conditions, other supplements, and foods.
For example, 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, and taking zinc sulfate with black coffee has been shown to reduce the mineral’s absorption by half.
Risks of too much zinc
Too much zinc in supplement form can trigger adverse effects that include nausea, vomiting, loss of appetite, abdominal cramps, diarrhea, and headaches. Excess zinc can also alter the body’s copper status and iron function, reduce immunity, and lower blood levels of “good” HDL cholesterol. 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. A long-term intake above the UL increases the risk of adverse health effects, unless supplemental zinc is prescribed and monitored by a physician for a specific medical condition.
In other words, more zinc isn’t better, and as noted, some of the risks associated with excess zinc are similar to those of a zinc deficiency. 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. One recent study found that common-cold patients who were given zinc lozenges recovered faster. After five days, 70% of the zinc patients had recovered compared with 27% of the placebo patients.
However, a 2020 study published in the British Medical Journal found that zinc acetate lozenges had no impact on common cold recovery rate compared to a placebo when used for five days after the first symptoms began. And documented 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.
Finding 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 dislikes or dietary restrictions, talk to your doctor or dietitian for guidance and whether zinc supplements might be appropriate for you. Zinc is one of the most important nutrients for optimal wellness, but 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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