Zinc and the Immune System: FAQ on the Safe Use of Zinc Supplements

Zinc is an essential mineral that the body needs. It helps in growth and development, DNA creation, and wound healing. It also helps maintain our sense of taste and smell. Despite all of this, we mostly hear about zinc when people are talking about the immune system.

Many people swear this mineral can help prevent colds and other illnesses. There are a lot of supplements with zinc in them that claim to boost our ability to fight off germs. But is zinc really a miracle ingredient? And is there such a thing as too much zinc?

We asked Nora Tossounian, M.D., an internal medicine physician at Hackensack University Medical Center, about the importance of zinc for our immune systems and the benefits and risks of taking zinc supplements.

Does Zinc Help Our Immune Systems?

Dr. Tossounian says we should think of zinc as the gatekeeper for the immune system. “It doesn’t supercharge it, but it ensures that it functions correctly,” she says.

When we encounter viruses or bacteria, our bodies send an army of cells, such as T-cells and natural killer cells (yes, that’s what they’re really called), to destroy the intruders. These are the body’s first line of defense, and they need zinc to develop and function correctly.

Zinc also helps regulate the immune system, which can help prevent inflammation and tissue damage.

How Much Zinc Do We Need?

The recommended daily allowance of zinc is 8 mg for adult women and 11 mg for adult men. The good news is that it’s easy to get this through food.

Foods High in Zinc

If you like oysters on the half-shell, you’re in luck because they are very high in zinc. Other meat-based sources of zinc include:

• Red meat (like beef and lamb)
• Shellfish (like crab and lobster)
• Poultry (like chicken and turkey)

There are also plenty of plant-based sources of zinc, including:

• Beans
• Nuts (like cashews and almonds)
• Chickpeas
• Pumpkin seeds
• Whole grains
• Fortified breakfast cereals

The good news is that most people get enough zinc in their day-to-day lives without needing to change their diet or take a supplement.

What If You Don’t Have Enough Zinc?

Zinc deficiency is rare in the United States because of the variety of foods we have available to us. Older adults and individuals with gastrointestinal diseases like Crohn’s or celiac may be at higher risk. Symptoms of zinc deficiency include thinning hair, an impaired sense of taste, skin rashes and digestive issues.

Dr. Tossounian warns against diagnosing yourself with zinc deficiency. She says, “Because the symptoms overlap with many other conditions, the only reliable way to know if you are deficient is to consult your doctor. They can assess your diet and symptoms and order a simple blood test to measure your zinc levels.”

Should You Take Zinc Supplements?

There are a lot of supplements on the market that promise to harness the power of zinc to keep us healthier. Dr. Tossounian thinks we should be skeptical of these claims. “The immune system is incredibly complex and cannot be boosted by a single ingredient. If a product sounds too good to be true, it almost always is,” she says.

She also points out that supplements are not regulated by the U.S. Food and Drug Administration the way prescription drugs are. The claims each supplement brand makes about its product’s purity, efficacy and safety do not have to be backed by science.

There is some research that suggests taking zinc supplements (usually in the form of syrup or lozenges) within 24 hours of your first symptoms might help shorten the length of a cold. And Dr. Tossounian notes that your doctor might put you on a high dose of zinc (the safe limit is 40 mg/day) temporarily to treat a deficiency or to help your immune system when you’re sick.

That said, high doses of zinc and long-term use of supplements are not usually recommended.

Is Too Much Zinc Dangerous?

Taking too many zinc supplements might mean your body doesn’t have enough copper. Copper deficiency can be very dangerous.

Dr. Tossounian explains it this way: “Zinc and copper are absorbed in the small intestine using the same transport pathways. When you flood your system with high-dose zinc, it monopolizes these pathways, effectively blocking copper from being absorbed into your body.”

Your body needs copper to create red blood cells and protect your nerve fibers. Copper deficiency can lead to anemia and irreversible nerve damage. Copper is also essential for your immune cells, which means that taking too much zinc could actually leave you more susceptible to infections.

Long-term intake of high-dose zinc has also been shown to lower levels of high-density lipoprotein (HDL) or “good” cholesterol. Even in the short term, taking too much zinc can lead to nausea, vomiting, stomach cramps and diarrhea.

Dr. Tossounian also warns that excess zinc can interfere with the absorption of certain medications, including some antibiotics and diuretics (medications that help the kidneys flush excess water and salt from the body).

Copper deficiency can be a particular problem for adults over the age of 50, as they are more likely to have cardiac issues and take multiple medications.

What Are Other Ways to Keep Your Immune System Healthy?

Keeping your immune system healthy is important. There are ways to do it that have more benefits and fewer risks than taking zinc supplements. Dr. Tossounian suggests going back to basics:

• Eat a well-balanced diet. Your immune system relies on a bunch of nutrients, like vitamins C, D, A, iron, selenium, protein and, yes, zinc. A diet rich in fruits, vegetables, lean proteins and whole grains provides the tools your immune cells need.
• Get more sleep. This is easier said than done in our busy lives, but our bodies perform critical repair and regeneration while we’re asleep. Chronic sleep deprivation also raises your cortisol levels, which can lower your immune defenses.
• Exercise regularly. Being active — think brisk walking, bike riding or swimming — improves the circulation of immune cells throughout your body. This helps them detect and fight pathogens more effectively. Exercise also helps lower stress hormones like cortisol.

Zinc is essential for keeping your immune system running smoothly, but taking too much can do more harm than good. Instead of turning to supplements, focus on a balanced diet and other healthy habits.

Next Steps & Resources

• Meet our source: Nora Tossounian, M.D.
• To make an appointment, call 800-822-8905 or find a primary care physician near you.
• Learn more about primary care at Hackensack Meridian Health.