Zinc: Benefits, Risks, & How Much You Need

Known for its contributions to a healthy immune system, zinc has a starring or supporting role in dozens of clinical trials studying ways to prevent COVID-19 infection and improve outcomes. But zinc is far more than an immune booster. This mineral, which only comprises a measly 0.0036% of the body mass of a 150-pound human, is amazingly critical for many aspects of your health.

So, how does zinc work in your body? How can you make sure you’re eating foods high in zinc? Can you get it from food alone, or do you need to supplement? Is there such a thing as too much zinc? And can sucking on a zinc lozenge prevent or shorten the duration of a common cold? This article explores the ins and outs of zinc so you can get the right amount of this important mineral.

What Is Zinc?

Before we get into all that, here is a story:

One day, early in the 19th century, the Royal Navy came to the chemist and inventor Sir Humphrey Davy with a big problem. To protect their ships from a kind of mollusk that bore into wood, shipbuilders had been lining the bottoms of these vessels with copper. Unfortunately, the salt water quickly corroded the copper, leading to costly and highly inconvenient repairs. Could Davy come up with a solution?

Davy suggested attaching a “sacrificial metal” to the copper. His element of choice was zinc. The zinc would protect the copper by being degraded by the salt water, a process termed “galvanization,” later used to protect iron, steel, and other industrial metals from corrosion.

The story ends sadly for Davy, who was still in the Navy (yes, that’s a Billy Joel callback for all you “Piano Man” fans!). While the zinc stopped the deterioration of the copper, it also made it far more susceptible to weeds and barnacles by providing them with nutrients that they found appealing. But it highlights the power of zinc, which can protect not only copper and iron but us as well.

Zinc is a naturally occurring trace mineral that your body needs to fight off bacteria and viruses. The adult body contains about two to three grams of zinc — approximately the weight of a penny — which is stored mainly in fluid, bones, tissues, and organs. However, your body does not make zinc, so you need to get it from food or supplements.

Zinc is essential for growth in humans, animals, and even plants. (If your pecan tree isn’t producing nuts regularly, make sure you fertilize with zinc in late winter.) Zinc is used in cell division to create your unique DNA and plays a significant role in promoting wound healing. It’s also crucial to fertility as it helps maintain levels of the reproductive hormones testosterone and estrogen. Zinc also comes into play with the metabolism of fats and sugars, helping to regulate and express insulin. And, zinc is largely linked to your sense of smell and taste, although the exact way this occurs is unknown.

The Health Benefits of Zinc

As you can see, zinc is an essential nutrient for a healthy, functioning body. Here are seven important reasons to ensure you get enough zinc.

Does Zinc Help with Colds?

It appears that every immunological event relates in some way to zinc. There’s a strong connection between zinc deficiency and susceptibility to disease. A Cochrane Library meta-analysis of six studies that included over 5,000 children between two months old and five years of age found that zinc supplementation reduced the incidence of pneumonia.

And according to findings from a 2020 systematic review, zinc is effective in shortening the duration and severity of the common cold (by approximately 2.25 days, so don’t get too excited).

People infected by COVID-19 who are zinc-deficient develop more complications, are more likely to require hospitalization, have longer hospital stays, and are more likely to die. To prove that zinc can help with COVID-19 outcomes, one 2023 study found that oral supplementation with zinc decreased symptom duration, ICU admission, and death rates.

Zinc During Pregnancy

The World Health Organization estimated in 2013 that most pregnant women worldwide were at least somewhat deficient in zinc. This may contribute to the likelihood of poor birth outcomes and stunted infant development. Indeed, a global review of 21 randomized controlled trials found that zinc can reduce the risk of preterm birth.

The WHO recommends micronutrient supplementation (including zinc) for pregnant women at risk of zinc deficiency.

Zinc and the Brain

No, zinc is not the fictional brain-enhancing drug NZT-48 from the movie Limitless. Taking it won’t make you smarter or (spoiler alert) make you rich and powerful (or even look like Bradley Cooper).

Now, the good news. Many people can prevent age-related neurodegenerative disorders, like Alzheimer’s, with diet and lifestyle habits.

Getting enough zinc is a key part of this prevention strategy; it acts as an antioxidant, preventing oxidative stress in the brain that could otherwise increase your risk for neurodegeneration. In fact, an imbalance of iron and zinc ions (too much iron and not enough zinc) has been shown to lead to Alzheimer’s and Parkinson’s disease symptoms.

Zinc and Hormones

Zinc plays a huge role in regulating your hormones, including growth hormone, insulin, leptin, thyroid hormone, melatonin, and sex hormones. Getting enough zinc is important for ensuring your endocrine system is working properly. When it isn’t, your various organs and systems can’t communicate well, which can wreak havoc on your health, energy, and mood.

Zinc is also key for reproduction and plays a role in processes such as ovulation and fertilization. Zinc supplementation has offered improvement in symptoms for women with Polycystic Ovarian Syndrome (PCOS) and dysmenorrhea. And zinc benefits for men may include sperm motility and testosterone levels and, by extension, a boost in fertility.

Zinc and Diabetes

According to a 2015 review of both test tube and human studies, zinc has many beneficial effects on type 1 and type 2 diabetes. Specifically, zinc appears to play an important role in pancreatic β-cell (that funny-looking thing that looks like a capital B is a symbol for beta) function, insulin activity, glucose modulation, and the process by which diabetes develops and has complications.

However, it’s unlikely that zinc deficiency directly causes type 2 diabetes, but rather people with type 2 diabetes have lower levels due to insulin resistance.

So, if you’re trying to prevent, reverse, or manage diabetes, in addition to watching your weight and eating a largely plant-based diet, make sure you get enough zinc to keep your pancreas firing on all cylinders.

Is Zinc Good for Your Heart?

In a 2015 meta-analysis, researchers found that zinc supplementation significantly reduced total cholesterol, LDL “bad” cholesterol, and triglycerides, which are risk factors for heart disease when elevated. Studies show that having adequate levels of zinc in your body may help prevent plaque buildup in your arteries, which can protect your heart.

Zinc and Eye Health

Zinc works alongside vitamin A and other antioxidants to support eye health and normal vision. It helps vitamin A produce melanin, a protective pigment that’s found in your eyes (as well as in your skin and hair).

Not getting enough zinc can also worsen night vision. Some research indicates that zinc supplemented with antioxidant vitamins can slow the progression of age-related macular degeneration, a condition in which the central field of vision becomes blurred or lost over time. This is a pretty significant contribution, considering macular degeneration is the leading cause of blindness among the elderly in Western countries.

How Much Zinc Do You Need?

The Recommended Dietary Allowance (RDA) for zinc is fairly small compared to other vitamins and minerals. Although it increases from infancy to teenage years, it largely remains the same throughout adulthood.

Below are the RDAs for zinc based on age group:

• 0–6 months: 2 milligrams (mg)
• 7–12 months: 3 mg
• 1–3 years: 3 mg
• 4–8 years: 5 mg
• 9–13 years: 8 mg
• 14–18 years: 9 mg (girls), 11 mg (boys)
• 18+ years: 8 mg (women), 11 mg (men)
• Pregnancy: 11–12 mg
• Breastfeeding: 12–13 mg

What Foods Have Zinc?

While some animal products — particularly oysters — contain high amounts of zinc, a diet rich in whole plant foods can provide you with various plant-based sources of zinc.

For instance, whole grains, soy foods like tofu and tempeh, legumes, nuts, and seeds are all zinc-rich foods. A one-ounce (30-gram) serving of pumpkin seeds contains two milligrams of zinc, and the same amount of hulled hemp seeds provides three milligrams.

However, many plant-based zinc foods are also high in phytates, which can reduce zinc absorption. One way to combat this is to prepare zinc- and phytate-rich foods in a way that reduces phytate content. You can reduce the phytate content of grains and legumes by soaking, sprouting, fermenting, or simply cooking them before eating. (You heard it here first: don’t eat raw wheat berries or black beans. You’re welcome!)

To increase zinc absorption, you can also eat zinc-containing foods with a source of protein. Amino acids (found in plant-based foods such as nuts, seeds, and whole grains) bond well with zinc in the body. However, eating a wide variety of whole plant foods, in addition to being a commonsense approach to diet in general, can help ensure you get enough zinc and other trace minerals. For example, those nuts and seeds are high in protein and give you zinc as part of a total package of goodness.

While zinc and vitamin C are often combined in supplements aimed at reducing the duration and severity of the common cold, this is mainly because both micronutrients can have immune-enhancing properties.

Vitamin C boosts iron absorption but doesn’t have the same effect on zinc. However, citrate, often found in vitamin C-containing foods like citrus fruits, may help enhance zinc absorption. So, it doesn’t hurt to still eat vitamin C-rich foods like oranges, grapefruits, and lemons alongside foods with zinc.

Zinc Deficiency

It’s estimated that about 17% of the world’s population is deficient in zinc, with a higher incidence in South Asia and sub-Saharan Africa.

Early in life, zinc deficiency may manifest in children as stunted growth. Other symptoms may include lack of appetite, unintentional weight loss, loose stools, low energy levels, increased susceptibility to infections, loss of hair, skin rashes, impotence, and problems with vision, taste, or smell.

But how is zinc deficiency diagnosed?

Because its symptoms are fairly generalized across several conditions, formal diagnosis usually involves ruling out other disorders that can present similarly. Your doctor may do a complete blood count (CBC) panel to check for an infection or anemia. If zinc deficiency is suspected, a blood test can be ordered.

Normal zinc blood levels are between 0.66 to 1.10 mcg/mL for anyone over 11 years of age.

Are You at Risk for Zinc Deficiency?

The risk for zinc deficiency depends on the individual and involves factors like age, diet pattern, medical conditions, and certain lifestyle habits.

Many omnivores get a good deal of their zinc from oysters, beef, dairy, and other animal products. Oats, pumpkin seeds, lentils, and peanut butter can also be good sources. However, some plant-based eaters may tend towards the lower end of the range regarding dietary intake.

In addition, the absorption rate for foods rich in zinc can range from 16–50%, meaning that the remaining zinc passes through the body unused. But what does that mean for you?

Some research indicates that those who follow a plant-based diet may need to eat as much as 50% more zinc than the recommended amounts to compensate for loss of absorption due to phytates (a type of antinutrient) or take a daily zinc supplement.

As a result, plant-based eaters may experience greater rates of subclinical zinc deficiency than omnivores.

The good news is that an individual’s current zinc status may influence their absorption rate — meaning that your body can adapt to lower zinc status by better using the zinc it ingests.

High-Risk Individuals

If you fall into some of these other categories, you may also be at a higher risk for developing zinc deficiency:

• Pregnant and breastfeeding women appear to have a higher prevalence of zinc deficiency, which can have long-term consequences for mom and baby.
• Elderly individuals who tend to eat fewer zinc-rich foods and lead less active lifestyles.
• People who use alcohol chronically because alcoholism is linked to lower intracellular zinc levels and worsened immunity.
• People who smoke because tobacco smoke is high in cadmium, which appears to further reduce tissue concentrations of zinc in the body.
• Those with absorption disorders, such as ulcerative colitis, Crohn’s disease, celiac disease, or conditions with persistent diarrhea.
• People who use high-dose iron supplements because taking iron with zinc supplements or zinc-rich foods may impair zinc absorption.
• Plant-based eaters might also be at greater risk, particularly if they aren’t taking zinc supplements.

Zinc Supplements

As mentioned, zinc is one of the few minerals plant-based eaters may have difficulty absorbing in sufficient quantities from food alone. Generally, an estimated 17% of people are low in zinc, but it may be as high as 30% in vegans.

For this reason, plant-based eaters and people at a heightened risk for zinc deficiency may want to consider adding a zinc supplement. The best way to be 100% certain you’re getting enough every day is by taking a high-quality zinc supplement.

But there are a lot of zinc supplements out there. So, if you want to consider taking a supplement, where should you start? There are a few things to know.

Zinc supplements are available in capsules, tablets, liquids, gummies, and lozenges. There are also several types of zinc.

One of the most cost-effective and widely available zinc types is zinc gluconate, commonly found in cold and flu lozenges. However, some studies show that zinc picolinate and zinc citrate appear to have better absorption rates. And in one study, zinc bisglycinate was found to be 43.4% more bioavailable than other forms of zinc.

If you have trouble with acne, zinc sulfate may come with the added benefit of improving the appearance of your skin.

Zinc is best taken one hour before or two hours after a meal. Also, for cold and flu prevention, zinc works best if taken within 24 hours of symptoms to reduce the length and severity of illness.

Regarding which is best, it doesn’t seem like you can go wrong with most of the forms used in common supplements. However, some studies have linked zinc in nasal sprays to a loss of smell, so you might want to steer clear of those.

Zinc Precautions

With all the benefits of zinc we’ve looked at, you might think that more is always better. Unfortunately, it’s not. You can experience zinc toxicity and overdose on zinc if you take too high of a dose of zinc supplements. Signs that you’re getting too much zinc may include nausea, vomiting, loss of appetite, diarrhea, stomach cramps, and headaches.

If you get too much zinc over an extended period, you can experience additional side effects like decreased copper levels, reduced immunity (for instance, getting sick more often), and sometimes reduced levels of HDL (“good”) cholesterol.

Understanding the upper limits of zinc supplementation can help you make sure you’re not consuming an unwise amount.

In general, you’d probably have to take over 100 milligrams of zinc per day to start experiencing any adverse effects — almost 10 times the recommended daily dose. Symptoms generally become evident at 100–200 times the recommended daily dose, with levels as high as one to two grams per day.

It’s also noteworthy that supplemental zinc may interact with certain drugs and medications. For instance, some antibiotics, penicillamine (a drug for managing rheumatoid arthritis), diuretics, and even other minerals may interact or cause zinc absorption issues. It’s probably wise to speak with your healthcare provider before taking a zinc supplement, especially if you take other medications or mineral supplements.

The good thing about getting zinc from food, however, is that most serving sizes are well below 100 milligrams where symptoms of toxicity may occur. The only food that may pose problems is oysters, which can contain up to 74 milligrams per three-ounce serving. But if you’re following a plant-based diet, this is a moot point.

Recipes With Zinc-Rich Foods

As you’ll see below, incorporating zinc-rich plant-based foods into your diet doesn’t have to be hard! Try out oat flour in baking (like in the Berry “Scuffins”), incorporate more organic soy products (check out the Lemon Herb Tofu), and combine several sources of zinc (as seen in the Southwest Quinoa Salad). Plus, you get so many other nutrients in these dishes, including vitamin C, fiber, and iron!

1. Berry “Scuffins”

Zinc intake doesn’t get much tastier than this! Just one-half cup of oats provides 1.5 milligrams of zinc. (Have no fear — you cook the “scuffins,” so you can reduce those zinc-binding phytates.) The term “scuffins” is what you get when you combine a scone and a muffin, which means you can enjoy it for breakfast, as a snack, or as an after-dinner treat!

2. Lemon-Herb Tofu

Wondering about your zinc intake? One way to consume a decent amount of zinc in just one meal is to enjoy tofu (1.8 milligrams of zinc in every four ounces) on top of whole grains (one to two milligrams of zinc per cooked cup) along with your favorite veggies. Sprinkle nuts and seeds on top for some crunch, flavor, and an extra dose of zinc!

3. Southwest Quinoa Salad

Both black beans and quinoa are rich sources of zinc. Since they need to be cooked, much of the phytate content is eliminated, making that zinc available to you! They’re also both packed with iron. Moreover, the vitamin C in the salsa and peppers helps enhance iron absorption. The citrate in the lime juice allows your body to absorb more zinc from your meal. We’re saying that getting lots of nutrition on a plant-based diet can be simple — and, as this salad will prove to you, delicious!

Get Enough Zinc, But Not Too Much

Zinc is an essential mineral for immunity. It also protects your heart, brain, eyes, hormones, and more. Although you can get zinc from food, many people, including plant-based eaters, may want to consider soaking, sprouting, or fermenting grains and legumes to reduce phytate content and increase zinc absorption. Some may also want to consider supplementation to protect against the risk of zinc deficiency.

Tell us in the comments:

• Do you use a zinc supplement?
• What zinc-rich foods do you enjoy? Which can you add to your diet?
• Have you ever used a zinc product to help reduce the duration and severity of the common cold?

Feature image: iStock.com/ratmaner

Read Next:

• 8 Essential Minerals — What They Are, Why You Need Them, and How To Get Them

• 14 Top Foods for Immunity Support So You Can Stay Well During Cold and Flu Season