The immune system is complex, and different nutrients can have different roles in supporting immunity. Zinc is one of the more common nutrients brought up in the immunity conversation, so let’s take a look at what it does.

What does zinc do for the immune system?

Zinc helps the body’s different defense cells develop and function correctly.  Zinc is important for both the immune system’s rapid first line of defense against invading pathogens, the innate immune system, and the second line of defense, the adaptive immune system.

The innate immune system:When pathogens like infectious bacteria or viruses get into our respiratory tract or gastrointestinal system, the innate immune system responds by sending cells like neutrophils or macrophages to remove the threat. These cells attempt to swallow up the invading pathogen or create enzymes to destroy the pathogen. Zinc helps these cells develop and function correctly.

The adaptive immune system is sometimes described as the ‘memory’ of our immune system. Once we are exposed to a pathogen, our immune system can remember the identity of that pathogen for the future and quickly mount a defense specific to that pathogen. Zinc helps the T-cells and B-cells that make up our adaptive immune system develop and function correctly.

When the body doesn’t have enough zinc, it can’t develop as strong of an immune response.

Zinc also has roles in many other functions in our body, including growth and development, vision, and reproduction.

Do people get enough zinc?

Most people in developed countries get enough zinc through their diet, meaning their immune system isn’t missing the zinc it needs. For example, in the United States around 18% of people do not meet the Estimated Average Requirement (EAR) of zinc per day. This means most people are not zinc deficient, but  certain people may still benefit from eating more zinc in their diet.

In Europe, the average intake of zinc is above the recommended amount.

However, zinc deficiency is common in developing countries. About 17.3% of the world’s population is at risk of inadequate zinc intake.

Zinc recommendations range from 5 to 11 milligrams per day for adults, varying by each global region.

Where can zinc be found in food?

Zinc is mostly found in seafood, beef, poultry, beans, nuts, or fortified cereal. Sample values are in the table below, as well as their contribution to the recommended daily intake relative to daily United States recommendations.

Source: National Institutes of Health Zinc Fact Sheet for Health Professionals

Do supplements help with illness?

According to Kathleen Zelman, RDN, MPH, “zinc lozenges or syrup frequently are used to treat the common cold in adults. If taken within 48 hours of symptoms, zinc may help reduce the duration and severity of symptoms by up to 40 percent. According to a 2011 meta-analysis, daily elemental zinc dosage must be at least 75 milligrams to be effective. However, despite numerous trials, zinc supplementation remains questionable for treating colds. Further, zinc lozenges have been known to cause adverse effects such as a bad mouth taste and constipation, but there is no evidence of long-term harm.”

Additional Resources

The Role of Food in Maintaining Immune Health in Ageing

This article in Food and Nutrition Magazine is another great review of Zinc written by Kathleen Zelman, RDN, MPH.

Linus Pauling Institute’s summary of zinc.

To learn more about how COVID-19 is affecting the food and beverage industry, including changes in consumer preferences and purchasing behaviours, visit Kerry’s COVID-19 resource page.