But does science back up those immune-boosting and calorie-burning beliefs? Experts suggest there’s some truth to the claims.  

Health benefits of zinc 

Like other essential vitamins and minerals, zinc supports overall health. “Zinc is involved in the activity of many biochemical and metabolism-related reactions in the body,” Kathleen Garcia-Benson, a registered dietician nutritionist, tells Fortune. In fact, it is second only to iron in its concentration in the body.

Many people believe that taking zinc supplements can help prevent or stop colds. However, studies show there’s little to no evidence that zinc can ward off cold symptoms. Some research, however, does indicate that zinc can help cut a cold shorter if it’s started early on.

“Research suggests that zinc lozenges can reduce the duration and severity of the common cold when taken within 24 hours of symptom onset, likely due to zinc’s ability to inhibit viral replication and support the immune system’s response,” says Garcia-Benson. “However, more studies are needed to determine the optimal lozenge dosage and treatment strategies.” 

In addition to supporting immunity, zinc is essential for numerous processes in your body, including: 

• DNA synthesis: Zinc acts as a vital cofactor for various enzymes and proteins involved in the process of DNA replication, repair, and overall genetic stability. 
• Wound healing: Zinc’s role in wound healing is multifactorial, and it is required for collagen and protein synthesis, cell proliferation, and immune function, all of which are essential for tissue regeneration and repair.
• Taste and smell senses: Zinc is important in the functioning of taste buds and smell. A zinc deficiency can adversely affect these senses. 
• Growth and development: Zinc is vital for human development during pregnancy, childhood, and adolescence.

Can zinc boost metabolism?

Zinc plays an integral role in metabolic function. Research shows that it’s essential for the correct functioning of lipid and glucose metabolism, regulating and forming the expression of insulin.

However, when it comes to zinc’s ability to boost metabolism, the findings are murky.  

One 2019 study found that zinc supplementation along with a restricted calorie diet has positive effects in reducing body weight and body mass index (BMI), as well as a decrease in appetite in people with obesity. 

Garcia-Benson shares a different viewpoint.  

“Zinc is crucial for supporting various metabolic processes, however, it does not boost the metabolic rate in the sense of increasing metabolic rate or burning more calories,” she says. 

“There isn’t strong evidence to suggest that zinc increases metabolism beyond its natural levels in individuals who are not deficient. So while zinc is vital for a healthy metabolism, it’s not a direct enhancer of metabolic rate outside of deficiency.”

The side effects of too much zinc 

As the idiom goes, “too much of a good thing” isn’t always good. Some side effects of excessive zinc intake include gastrointestinal symptoms (nausea, vomiting, diarrhea, abdominal pain). 

“We want a healthy immune system, but not a ‘boosted’ overreactive one,” says Garcia-Benson. “Excessive zinc won’t trigger it to be overactive; however, there are other side effects from too much zinc.”

She adds, “Too much can also result in reduced magnesium absorption and copper deficiencies. While zinc is required for a healthy immune system to perform at an optimal level, there is a point when its requirement is met and more zinc will not increase immune system response.”

Zinc toxicity will dissipate as the excessive intake decreases. But some people may still experience long-term side effects from taking too much zinc, like a compromised immune system. 

While zinc plays an integral role in the body’s overall function and performance, moderation is key. 

How much zinc do you need?

The daily recommended dietary allowance is 8 mg for women and 11 mg for men. 

Supplements are the go-to for some, but people can easily get their recommended requirement simply by incorporating zinc-rich foods into their diet. 

Garcia-Benson suggests, “If regularly supplementing, consider tracking food intake for one week to determine if it’s really needed.”  

How to get zinc through food 

Although zinc is available as a supplement in the form of pills and lozenges, it’s also found in many foods and drinks. 

“Oysters, red meat, poultry, fish, legumes, nuts, seeds, dairy, whole grains, and fortified breakfast cereals are great sources of zinc,” Garcia-Benson says. “In general, zinc intake correlates well with protein intake.” 

She adds, “Cooked 3 ounces of lean beef provides roughly 9 mg of zinc; 1 cup of yogurt provides roughly 2.2 mg, and half a cup of chickpeas, or 1 ounce of walnuts, provides roughly 1 mg.” 

Research shows that the amount of zinc absorbed from food ranges from 5% to more than 50%, depending on the amount of plant-based foods in the diet. 

Who needs more zinc?

“A few groups of people are at a higher risk for zinc deficiencies, including those who’ve have had gastrointestinal surgery (including weight loss surgery), those with ulcerative colitis, Crohn’s disease, vegetarians, vegans, those pregnant or nursing, those with sickle cell disease, and infants 6 months and older,” Garcia-Benson says. 

Some common symptoms of a zinc deficiency include:

• delayed wound healing
• impaired appetite 
• impaired taste
• immune deficiencies 
• hair loss
• increased night blindness
• diarrhea 

The bottom line

Zinc helps you maintain a healthy immune system. It has been proven to reduce the severity and duration of colds, but cannot cure one. Zinc is also important for metabolic function, but don’t count on it to help you instantly shed pounds.

More on nutrition and supplements 

• It’s not 8 glasses a day anymore. Here’s how much water you should drink each day
• The 5 best supplements for healthy aging, according to a longevity expert
• Do turmeric supplements work?  Experts say, yes, for 2 conditions
• The 7 best zinc supplements of 2024, reviewed by a registered dietitian