Can You Really Boost Your Immune System With Food?

Ask Keri: Does my diet affect my immune system? I’m seeing so many mixed things during this coronavirus pandemic! 

Keri Says: As COVID-19 sweeps the nation, many people are wondering what they can do to stay healthy. But there has been some mixed information about whether or not you can boost your immune system with food.

Here’s the deal: Your diet provides many essential nutrients your immune system needs to function properly, but consuming high amounts of certain foods won’t necessarily offer additional benefit. On the flip side, a diet loaded with unhealthy foods can cause inflammation, which compromises your body’s immune system.

The confusion lies in the term “boost,” which infers that you can supercharge your immune system by consuming certain foods or supplements. Does diet influence immunity? Yes. Does eating certain foods make your immune system function better in the absence of a nutrient deficiency? Maybe not.

What the Research Says

Nutrients like vitamin C and zinc have been touted for their immune-boosting capabilities and potential to alleviate the common cold or flu. Vitamin C plays an essential role in the immune system by promoting the production of white blood cells, acting as an antioxidant to protect the body from damaging free radicals and strengthening the skin’s barrier against pathogens. 

RELATED: What Are the Health Benefits of Antioxidants? 

A 2013 systematic review of 29 trials found that daily vitamin C supplementation was able to reduce the risk of getting a cold for extremely active people like marathon runners, but it did not reduce the incidence of colds in the general population.

Similarly, a very limited number of randomized trials suggest that supplementing with zinc, which plays an important role in immune cell development and signaling, may reduce the duration of colds by 33 percent. That said, we need more research in different populations and with different doses and supplement types. 

Antioxidants and probiotics have also been promoted as immunity-boosters for their ability to reduce disease-causing inflammation and act as a barrier against pathogens, respectively. While these nutrients definitely play a role in the immune system, there is no strong evidence directly linking these nutrients to an enhanced immune response.

The reality is that the immune system is extremely complex and there’s still a lot that researchers don’t know when it comes to diet and immunity. It’s also important to note that research on the cold and flu cannot be extrapolated to the coronavirus. Any companies stating that their food or supplement will protect or prevent COVID-19 are making false claims that have not been researched.

Nevertheless, eating a well-balanced diet rich in nutrient-dense foods will ensure you’re consuming the essential nutrients your body needs to maintain a healthy immune system. Fruits and vegetables like peppers, oranges, leafy greens, carrots, and berries are great sources of gut-friendly fiber, vitamin C, and many inflammation-fighting antioxidants. Whole grains, legumes, and shellfish provide zinc, while yogurt and fermented veggies pack in beneficial probiotics. What’s more, if your diet is loaded with these filling, health-promoting foods, it also means there’s less room for the inflammation-causing stuff, like sugar. 

The Bottom Line

This is really a matter of semantics. No, food doesn’t “boost” your immune system in the sense that extra nutrients probably won’t improve your immune function if you don’t have a deficiency. That being said, the immune system does rely on essential nutrients derived from food, so eating a nutritious diet is one way to support a strong immune system. 

Ultimately, there’s still a lot of research that needs to be done to understand the exact relationship between lifestyle factors and immunity, but eating your fruits and veggies (plus sleeping well and hydrating!) never going to hurt.


(Featured photo: Shutterstock)

About Nutritious Life Editors

The Nutritious Life Editors are a team of healthy lifestyle enthusiasts who not only subscribe to — and live! — the 8 Pillars of a Nutritious Life, but also have access to some of the savviest thought leaders in the health and wellness space — including our founder and resident dietitian, Keri Glassman. From the hottest trends in wellness to the latest medical science, we stay on top of it all in order to deliver the info YOU need to live your most nutritious life.

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