Healthier, happier: Diet is one way to decrease risk of coronavirus

Fiber in our diets feeds the bacteria in our intestines, which play a crucial role in our immune system function.

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Dr. Jason Buffington

The COVID-19 illness has certainly changed our lives.

Health experts, as well as the media, have made it known that social distancing, wearing face masks and frequent hand-washing are the most effective ways to prevent transmission of the disease to others and minimize our own exposure to the virus. But we don’t hear much, if anything, about other proactive steps we can take to decrease our risk of the disease and its complications.

The SARS-CoV-2 is a brand-new virus, so there are not many studies specific to it, but medical research is full of studies regarding lifestyle factors and their influence on the immune system and other infections, such as influenza.

The most influential lifestyle factor on our immune system is our diet. Everything we eat and drink affects our immune system, either positively or negatively. If you research scientific studies, you will find many foods, nutrients and supplements that have been analyzed regarding the immune system. Let’s focus on five main groups of food/drink that have special immune-boosting benefits: fiber, alliums, cruciferous vegetables, tea and salads/spices.

Fiber in our diets β€” which is only found in whole-plant foods, with the highest amounts in legumes and whole grains β€” feeds the bacteria in our intestines, the gastrointestinal microbiome. These bacteria play a crucial role in our immune system function, helping form a barrier between the GI and respiratory tract and the bloodstream, and training and modulating our immune system through chemicals secreted, such as redox molecules and short-chain fatty acids. Studies show as much as 80% of our immune system lines our GI tract, with the microbiome directly influencing it.


Alliums are the garlic and onion family. They contain many beneficial ingredients that support our immune system, including fiber and allicin, a phytonutrient that has direct antiviral and immune-boosting properties.

Cruciferous vegetables like kale, cabbage, broccoli, cauliflower, radishes and asparagus also contain fiber, but are more known for their high level of sulfur-containing compounds that help our immune system fight infections.

Tea, especially green tea, is high in immune-boosting antioxidants and phytonutrients, such as catechins, which have been proven to help lower rates of viral infections like influenza and lessen the severity of symptoms if contracted.

Salads and spices are also well-known in the scientific literature to help boost our immune systems and help prevent and fight viral infections. Dark leafy greens, such as kale, swiss chard and spinach, are especially high in immune-enhancing antioxidants and help our bodies produce nitrous oxide, a strong antioxidant and potent dilator of blood vessels, improving blood flow to our organs. Spices, notably bay leaves, rosemary, turmeric and ginger, have been found in studies to be effective in preventing and fighting viral and respiratory infections and modulating inflammatory reactions. Berries and other brightly colored produce are also very high in antioxidants.

So be avid with hand-washing and mask-wearing, and smart with your social interactions, but also take advantage of this challenge to become a healthier eater. Enjoy oatmeal with berries and pumpkin pie spice and a cup of green tea for breakfast; vegetable bean soup with plenty of spices, onions and garlic and a side spinach salad for lunch; and maybe a lentil curry bowl with onions, ginger and curry spices over brown rice and kale for dinner, all loaded with immune-boosting fiber, antioxidants and phytonutrients!

Dr. Jason Buffington practices lifestyle medicine at Essentia Health.

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