Am I Taking Too Much Zinc?

Maybe you associate zinc with the periodic table. Or maybe you think of it as a remedy when you have a cold. Or maybe the word conjures up images of chalky white sunscreen. Turns out, you come into contact with the mineral way more often than you might think. But what exactly does it do, and can you overuse it?

It's a powerful antioxidant and mineral that plays a key role in boosting the immune system, says Lisa Moskovitz, RDN, the CEO of the private nutrition practice New York Nutrition Group.

As such, you’ll find it on the ingredient list for cold remedies including lozenges and nasal sprays like Zicam. You can buy supplements that are literally just “zinc,” and it also pops up as an ingredient in other pills: Some probiotics include it, as do some hair health supplements.

The mineral is essential to overall health — in addition to supporting immune function, the body also needs it to make proteins and DNA. It's important to consume it daily because it can't be stored in organs or muscle tissue. Luckily, foods like meat, legumes, eggs, dairy, whole grains, and nuts have plenty of it. 

There are also benefits to upping your zinc intake during cold and flu season, says Tracy Lockwood Beckerman, RDN, author of The Better Period Food Solution. Many colds are caused by the virus "rhinovirus," which flourishes in areas like the nasal passages and the throat, according to the Mayo Clinic. Zinc may stop the bug from lodging in these mucous membranes and multiplying. If you think you have cold symptoms and you take zinc within 48 hours, Beckerman says it may reduce the severity of your symptoms by up to 40 percent.

Though the exact dose for optimal health varies based on factors such as height and weight, most people need between eight to 11 milligrams of zinc per day, the National Institutes of Health notes.

And good news—you're probably already hitting that range. Moskovitz says that research shows the average adult in the U.S. gets about nine to 13 milligrams daily. In fact, Beckerman says that research indicates that only 8 percent of people above age two fall short on the average requirement. (Deficiencies cause symptoms like thinning hair, weight loss, and oral ulcers; see your doctor if you think you have one.)

If your main source of zinc is food, it's not likely that you'll wind up overdoing it, Beckerman says. If you're taking supplements that contain zinc, though, you're at greater risk of exceeding the upper limit for safe consumption, which is 40 milligrams per day, Beckerman explains. And once you take in more than that amount, “the body tries to get rid of it through diarrhea, vomiting, stomach cramps and headaches,” she says.  

Beckerman adds that long term overuse of zinc can perpetuate other issues like copper deficiency, which makes you more susceptible to sickness and causes issues like fatigue. “Plus, persistent use of zinc-containing nasal sprays can result in the loss of sense of smell,” she adds. “Yikes.” 

In addition to people who are trying to stave off a cold, the group of people who most commonly take zinc supplements (and are therefore at risk of getting too much) are vegans and vegetarians. They often use zinc pills because plants tend to have less of the mineral than meat or fish, Beckerman says.

It's fine to take the mineral for a few days in a row to stave off a cold. But you should always talk to your doctor before popping zinc daily to make sure a regular dose is safe for you and you're taking a safe amount. And since zinc can be found in unexpected supplements, look on the label of any pill you're taking daily (not just plain zinc supplements) to keep tabs on your intake.