Zinc: everything you need to know

Zinc is an essential micronutrient that your body needs in order to function properly. Your body can’t make zinc so you must get it from food or supplements.

Below, we’ll walk you through everything you need to know about zinc including how it helps your body stay healthy and how much you need for optimal health.

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Zinc is a trace mineral, meaning that you only need a small amount of it per day. The only catch is your body can’t make zinc on its own. Your body also doesn’t store this mineral, so you need to make sure you get enough daily through either food or zinc supplements.

Zinc helps keep cells in your body functioning properly. For example, zinc plays a role in promoting enzyme function. This helps your body do things like break down carbohydrates, secrete insulin, and maintains your sense of taste and smell (Morris, 2021). 

Zinc is also crucial for skin health, immune function, cell growth, and wound healing (Rabinovich, 2021). 

Zinc has a multitude of health benefits. Here is an overview of the main ones.

Supports immune function 

Zinc is essential to maintaining white blood cells. Studies suggest that zinc supplements may improve your ability to fight off infections like the common cold (Wessels, 2017). 

One study found that oral zinc supplements or dietary zinc helped people get over a cold 30% faster, especially when taken at the first sign of cold symptoms (Hemilä, 2017). 

However, if those sniffles are due to COVID-19, research shows zinc may not do much. One clinical trial found that the use of high-dose zinc supplements didn’t shorten how long people experienced COVID symptoms (Thomas, 2021).   

Treats diarrhea

The use of zinc can be a short-term solution for treating diarrhea in children, mostly in developing countries. The recommended dose is 20 mg daily for adolescents and 10 mg for babies younger than six months (NIH, 2021). 

Another recent study found that lower levels of zinc for kids still effectively treated diarrhea and reduced the chance of vomiting or upset stomach (Dhingra, 2020).

Helps with fertility 

Zinc intake may play a role in promoting fertility in both men and women. Studies looking specifically at zinc’s effects on testosterone are limited, but some show that low zinc can interfere with testosterone levels, which are needed for healthy sperm production (Fallah, 2018; Terrin, 2015). 

Delays vision loss

A review of studies found that antioxidants like zinc play a role in preventing age-related macular degeneration, an eye disease that causes vision loss.

Studies have found that supplementing with antioxidants may halt the progression of the condition, though more research is needed to determine if long-term supplementation of certain antioxidants is harmful (Evans, 2006).

There are two main sources of zinc: food and supplements. Most people will be able to get enough of this mineral through diet alone. 

Foods high in zinc

The National Institutes of Health (NIH) lists there are many foods that are good sources of zinc including (NIH, 2021):

• Shellfish: Oysters, crab, and lobster

• Fish: Flounder and sole

• Meat: Beef and pork

• Poultry: Chicken and turkey

• Legumes: Peas, kidney beans, baked beans, and chickpeas

• Nuts and seeds: Pumpkin seeds, cashews, and almonds

• Dairy: Yogurt, milk, and cheddar or mozzarella cheese

• Whole grains: Bran and wheat germ 

• Fortified foods: Oatmeal and some breakfast cereals

Zinc supplements

In addition to your dietary intake, you can also take zinc supplements. If you don’t have a zinc deficiency taking supplements won’t hurt you (as long as you don’t swallow too many––more on that below), but the jury is still out if you’ll actually benefit from them. 

When shopping around, you may see different forms of elemental zinc like zinc gluconate, zinc acetate, and zinc sulfate. Zinc gluconate and acetate are typically found in cold medications like nasal sprays (Hunter, 2021). Zinc sulfate is beneficial for topical formulations for treating skin conditions like acne (Cervantes, 2017).

Just be mindful that this trace element can inhibit copper absorption (which your body also needs) and supplementing can accidentally create a copper deficiency (NIH, 2021). 

The amount of zinc your body needs varies based on factors like age and if you’re pregnant or nursing. 

The general recommended dietary allowance (RDA) is 8 mg for adult females and 11 mg for adult males. Pregnant women should get about 11 mg and lactating mothers require roughly 12 mg of zinc daily (NIH, 2021).

The tolerable upper level—or maximum amount considered safe—is 40 mg per day for healthy adults. This, however, is not the case for someone with a zinc deficiency (NIH, 2021).

In North America, zinc deficiencies are uncommon but not totally unheard of. Certain groups of people are also at higher risk for developing zinc deficiency than others. 

In mild cases, signs of a zinc deficiency include loss of appetite and low immune function. In more severe cases, symptoms can cause hair loss, diarrhea, impotence, and eye or skin lesions (NIH, 2021). 

Those most at risk for a zinc deficiency include pregnant women, vegetarians, and those with gastrointestinal or digestive problems that inhibit zinc absorption (NIH, 2021).

Just like too little can cause problems, too much zinc can also lead to side effects. This mostly pertains to supplemental zinc––there’s not much evidence that people overdose on zinc from food sources. Symptoms of zinc toxicity include (Bartzatt, 2017): 

• Fatigue

• Nausea

• Vomiting

• Problems breathing 

• Fever

• Anemia

Although zinc is considered relatively non-toxic, it’s important to not overdo it and follow any medical advice while taking supplements (Bartzatt, 2017). 

If you want to use zinc nasal sprays, make sure to talk to a healthcare provider first. In 2009, the U.S. Food and Drug Administration (FDA) advised against using three zinc-containing nasal sprays because they were linked to temporary loss of sense of smell (NIH, 2021). 

Your body needs zinc to function properly and support your immune system. It also interacts with other important vitamins and minerals like calcium, vitamin A, and vitamin C. You should be able to get enough daily by consuming some of the foods listed above. Before taking any dietary supplements like zinc, consider talking to a healthcare professional first.

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How we reviewed this article

Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Current version

March 21, 2022

Written by

Kaitlin Sullivan

Fact checked by

Felix Gussone, MD

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About the medical reviewer

Felix Gussone, MD, Ro

Felix Gussone is a physician, health journalist and a Manager, Medical Content & Education at Ro.