Got zinc? That may be the question of the moment, especially if you’re popping zinc supplements like candy in hopes of building your immune system. Yet immune function is a complicated topic, and while having the right amount of zinc on board could help prevent infections, taking excess zinc may not be the best strategy.

When you don't have enough zinc, you are more likely to get sick from infections 

Zinc is a mineral with numerous roles in your body. Not only do a multitude of enzymes need it to function, it also assists in hormonal activities, such as protein and DNA synthesis, wound healing, bone structure and immune function, says Julianne Penner, M.S., R.D., dietitian at cardiopulmonary rehabilitation at Loma Linda University Medical Center in Loma Linda, Calif.

With COVID-19 running rampant, zinc’s role in immune functioning has received particular attention recently– and for good reason. “When your body doesn’t get enough zinc, the immune system is compromised and doesn’t work as well,” says Emily Ho, Ph.D., director of the Linus Pauling Institute at Oregon State University in Corvallis. In some cases, that may cause it to overreact by creating inflammation, or it may not work as well to fight off infections. The upshot? “When you don’t have enough zinc, your ability to get sick from infections will increase.”

The trouble is, there isn’t an effective test for zinc deficiency. What can decrease your zinc: If you have copper pipes in your house (zinc competes with copper for absorption, so trace amount of copper will negate the body's update of zinc); taking calcium supplements can deplete zinc as can exercise, drinking alcohol and viral infections. If you have diarrhea that can also deplete your zinc, and the majority of tests that exist for measuring zinc are not accurate, Penner says. You can be watchful for symptoms of zinc deficiency, which shows up in small clues, like white specks on your fingernails, unusual hair loss, recurrent infections, diarrhea or and skin changes, but outside of that, you’re often left to guess.

How to fill your body's zinc for a healthy immunity

Current dietary guidelines recommend that women aged 19 and up get 8 milligrams (mg) of zinc per day (that increases to 11 mg if you’re pregnant, 12 mg if you’re lactating), while men should get 11 mg per day. Although many animal foods contain zinc, it is possible to get enough zinc you need on a plant-based diet, Penner says.

The Best plant-based foods that are rich sources of zinc:

  • Firm tofu -- 4 mg per cup

  • Hemp seeds -- 3 mg per cup

  • Lentils -- 3 mg per cup

  • Oatmeal -- 2 mg per cup

  • Pumpkin seeds -- 2 mg per 1 ounce

  • Quinoa -- 2 mg per cup

  • Shiitake mushrooms --2 mg per cooked cup

  • Black beans -- 2 mg per cup

  • Green peas -- 2 mg per cup cooked

  • Cashews -- 2 mg per 1-ounce

  • Spinach -- 1mg per cooked ounce

  • Lima Beans -- 1 mg per ounce

  • Chia Seeds -- 1 mg per ounce

  • Pecans -- 1 mg per ounce

  • Avocados -- 1 mg per ounce

  • Flax Seeds -- 1 mg per ounce

  • Asparagus -- 1 mg per ounce

 (Source: MyFoodData)

Yet increasing evidence suggests that individuals who are at higher risk for infections or those over 60 may need even more zinc than doctors once thought. “Dietary survey data suggests that among this population, close to 40 percent may not be eating the zinc they need,” Ho says. Because many older adults don’t eat as much protein-rich foods, which is where zinc is mainly found, they could be falling short. Research shows that people over 60 have more trouble utilizing and absorbing the zinc they are getting, which is why taking a zinc supplement may be a good idea, Ho says.

Another group that may need to up their zinc intake? Plant-based eaters, which is why Ho recommends that strict plant-only eaters double their intake. “Plant-based foods often contain phytates, which binds to zinc and can interfere with absorption,” says Ho, who takes a multi-mineral, multivitamin to supplement her predominantly plant-based diet. If you want to go this route, check that the label has zinc listed as an ingredient, as many popular daily supplements don’t contain zinc.

In the age of COVID-19, is more zinc better for strengthening immunity?

This is the million-dollar question that everybody’s asking: Will more zinc provide greater infection-fighting potential, especially if you already have normal levels of zinc?

While there is evidence that zinc can help your body fight a cold, if taken in the first 24 hours of symptoms showing up, its role against COVID-19 is unknown. And in clinical trials that show zinc can help fight infection, it’s unclear whether study subjects started with a zinc deficiency or not. “For those people taking a zinc supplement who show benefits, you don’t know if they’re reversing a potential zinc deficiency and that’s why they’re benefiting or if they had normal levels of zinc to begin with and the extra zinc is giving them a boost,” Ho says.

And although zinc itself isn’t necessarily harmful, it is possible to get too much. “If you’re consuming lots of extra zinc over several months, it can compete with other essential minerals like copper and iron,” Ho says. As a result, you could become deficient in those minerals, which can lead to other health issues. At high doses, zinc can also create toxicity, causing nausea, vomiting, loss of appetite, abdominal cramps, diarrhea and headaches according to the National Institutes of Health (NIH).

If you do want to up your zinc during the continued spread of COVID-19, there’s probably no harm in doing so for the short-term, especially if you suspect you’re low in zinc. “It may be a good idea to take zinc during the pandemic, but like many aspects of COVID-19, it hasn’t been studied yet,” says Dana S. Simpler, M.D., internal medicine physician with Mercy Medical Center in Baltimore, Md., adding that 50 mg per day is the recommended amount to prevent catching colds or speed recovery from colds.

Aim to get it through food first, which eliminates the worry for toxicity and other problems, Penner says. Then if necessary, you can take a supplement, veering toward one with zinc picolinate, a type of zinc that’s absorbed more easily into the body than others (check the label for this term). Watch the amount of zinc, though, as the NIH notes that adverse effects have been shown with as little as 60 mg/day for up to 10 weeks.

Just remember that zinc isn’t a silver bullet when it comes to protecting your body from infections and viruses like COVID-19. “Zinc is just one of the many nutrients that will benefit your immune system,” Ho says. Get sleep, exercise, eat a healthy plant-based diet of mostly fruits, vegetables, whole grains, legumes and nuts and seeds, and keep your stress levels in check. Everything you do to boost immunity will be another helpful piece of the puzzle to stay healthy and keep your chances of all infections lower. And wear a face mask!