With cold, flu and COVID season looming, one of the easiest ways to strengthen your immune system is by getting enough zinc.
But some people — including those who don’t eat meat or those with certain intestinal conditions — might have to work a little harder to get the right levels. The good news is that nutrition experts have lots of smart ideas to help you get there.
Zinc is the gatekeeper of your immune system.
Registered dietitian (RD) Amy Goodson said zinc is important for your overall health. “It’s an essential mineral that plays a crucial role in various bodily functions, including immune response, wound healing, DNA synthesis and cell division,” she said. “It’s particularly important for immune function, because it helps activate T lymphocytes, also known as T cells, which are critical in defending the body against pathogens.”
RD Jerlyn Jones described zinc as the gatekeeper for the immune system. “It functions as an antioxidant, which means that it helps protect cells in the body from damage caused by free radicals,” she said. Erika Siegel, a naturopathic practitioner, pointed out even more of zinc’s important work: “It has a major impact on hormonal balance, including thyroid hormone synthesis and reproductive health.”
Even if you do get sick, zinc helps you get better more quickly, she said, noting, “Research shows that zinc can interfere with the process allowing mucus, bacteria and viruses to build up within the upper respiratory tract, so zinc can significantly shorten the duration of an infection.”
Are you getting enough zinc?
The recommended dietary allowance for zinc is 8 milligrams per day for women and 11 milligrams per day for men. Pregnant people need slightly more zinc (11 milligrams daily) and those who are lactating need the most — 12 milligrams per day.
When you’re eating zinc-rich foods regularly, it’s fairly easy to get enough each day. “For example, 3 ounces of lean beef has 5 milligrams of zinc, which is more than 50% of what a woman needs and almost 50% of what a man needs every day,” Goodson said.
These are the best foods that contain zinc.
Luckily, foods that contain zinc are not only readily available, but they taste pretty good, too.
First, if you love bivalve mollusks, you now have a good excuse to indulge. “Oysters are the best way to get in the recommended amount of zinc a day,” said functional medicine RD Rebecca Russell. In fact, there are more than 11 milligrams of zinc in just 1 ounce of fresh oysters. There’s also significant zinc in other animal proteins like meat, fish and seafood, as well as some in eggs and dairy products.
But there are non-animal-based options, too. Registered dietitian nutritionist Sharon Palmer weighed in on the outlook for those who are vegetarian or vegan. “Beans, nuts, seeds, grains and some fortified cereals also contain significant levels of zinc, though they can be slightly less absorbed by the body than those in animal sources,” she said.
For Palmer, who describes herself as “the plant-powered dietitian,” pulses, the edible seeds in the legume family that include chickpeas, lentils and beans, are a frequent go-to. “I eat pulses almost every day,” she said. “I also eat a few daily servings of whole grains, such as oats, whole-grain breads and rice, and a serving of nuts or seeds, too.”
A 3.5-ounce serving of chickpeas contains 1.5 milligrams of zinc, a serving of lentils has 3.7 milligrams and most dried beans contain a little over 1 milligram of zinc per serving. A serving of oats has about 4 milligrams of zinc, a slice of whole-wheat bread has about 0.54 milligrams, and a serving of brown rice has 0.9 milligrams. Nuts and seeds can have from 1 to 3 milligrams of zinc per ounce.
Other nutrition experts have their own favourite ways to add zinc to meals. “I add lentils to soups and salads, have oatmeal sprinkled with pumpkin seeds, and I grill shrimp to serve with vegetables,” Jones said. An ounce of roasted pumpkin seeds contains 2.2 milligrams of zinc, and shrimp has 1.64 milligrams of zinc in a serving.
Not all zinc is absorbed equally.
Even if you’re eating enough zinc, though, your body may not be using it efficiently. The absorption rate of zinc from food ranges from 5% to 50%, Russell said. The culprit in slow absorption is a compound called phytate, which is found in plant-based foods like grains, nuts, seeds and vegetables. Russell explained how it works with other foods in your body: “The phytates from plants bind to minerals in the intestine, which then reduces zinc’s absorbability.”
There are ways to address this issue, said Siegel, who praised the effect of the antioxidant flavonoid known as quercetin. “It helps enhance the absorption of zinc by increasing the uptake into the cell,” she said. However, Siegel advised some people should be cautious when it comes to quercetin: “While usually considered safe for most people to take in doses of up to 1,000 milligrams per day, it should be avoided by people with a history of kidney disease or caffeine sensitivities.”
Another absorbability suggestion came from Palmer. “It’s been found that sprouting and leavening can help bioavailability,” she said. Sprouting is a method of soaking seeds, nuts, legumes or grains until they sprout, and leavening is the process of adding air or carbon dioxide bubbles into breads and batters to lighten and soften the dough, usually through yeast, baking soda or baking powder.
Depending on your diet, you may want to consider other ways to increase zinc levels. “Certain individuals may not get enough zinc, such as vegans, people with inflammatory bowel disease or those who have had bariatric surgery,” Jones noted. “They may benefit from taking zinc supplements.”
Taking supplements? Keep reading.
“When considering zinc supplementation, both the form of zinc and the brand you choose are crucial,” Russell said. “The bioavailability, which is the body’s ability to absorb and use the nutrient, varies significantly with different forms of zinc.” Zinc picolinate, zinc citrate, zinc acetate and zinc bisglycinate chelate are some of the most easily absorbed. On the other hand, zinc sulfate is the least easily absorbed, though it tends to be the cheapest.
“Equally important is selecting a reputable supplement brand that conducts third-party testing to ensure the purity of its products,” she said.
Always take zinc supplements with food, as they can cause nausea otherwise, Siegel said. And steer clear of nasally administered zinc. “It’s been linked with the loss of the sense of smell, known as anosmia, and there have been class-action suits against Zicam nasal spray or gel swabs,” she said. In 2009, federal drug regulators warned consumers to stop using the product because it could damage or destroy their sense of smell. Since then, Zicam says it has reformulated its products; however, as a homeopathic medicine, it isn’t regulated by the Food and Drug Administration.
Can I take too much?
More is not necessarily better, and you should limit intake to no more than 40 milligrams of zinc per day for adults. But as long as you’re getting zinc through food, not supplements, you should be OK. “It’s hard to consume too much zinc from food alone, unless you’re eating a lot of oysters every day,” Russell said.
If you’re taking supplements, Goodson said to be aware of possible reactions. “Excessive zinc intake can cause nausea, vomiting, loss of appetite, stomach cramps, diarrheoa and headaches,” she said. “Chronic high zinc intake may also lead to copper deficiency, weakened immune function and disruption of iron absorption.”
It’s important to note all the ways you’re getting zinc in your diet and make an accurate tally. “Many multivitamins also contain zinc, so read the labels,” Palmer said. “Also, check the labels on fortified foods like cereals.”
It’s all part of a bigger picture.
Finally, Russell noted that no single vitamin or mineral can work by itself. “Zinc can play a key role in boosting immunity, but it’s just one part of the puzzle,” she said. “We also need to focus on gut health and other essential nutrients to support a strong immune system. With health, there’s never a single magic solution. It’s the combination of diet, lifestyle and various factors that work together to create a robust immune system.”