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Experts say the foods you choose can affect inflammation in your body, a risk factor for COVID-19. miniseries/Getty Images
  • Researchers report that the foods in your diet can increase or decrease risks associated with COVID-19.
  • They said that foods such as coffee and kale, as well as breast milk, can reduce COVID-19 risks because they keep inflammation in the body in check.
  • They add that tea, red meat, and fruit don’t seem to have an impact one way or the other, while processed meats such as hot dogs can raise risk factors.

What do coffee, breast milk, and kale have in common?

They all have the power to modestly reduce your COVID-19 risk factors, according to a new study on how nutrition affects immunity.

Researchers from Northwestern University in Chicago used UK Biobank data to examine the association between dietary behaviors from 2006 to 2010 and COVID-19 cases from March through November 2020 in the same people.

The study included 38,000 participants who had received a COVID-19 test. About 17 percent tested positive for the coronavirus. The specific foods used in the study were shown to affect the immune system in earlier human and animal studies.

Foods that reduced COVID-19 risk by 10 percent were:

  • coffee (1 or more cups a day)
  • vegetables (2/3 serving, cooked or raw, excluding potatoes)
  • breast milk (having been breastfed as an infant)

Foods that had no impact included tea, fruits, and red meat.

Processed meats such as hot dogs and deli meats were associated with higher risk. Even half a serving of processed meat daily can increase COVID-19 risk by 10 percent, the researchers said.

But how?

The study may not be able to determine cause and effect, but experts suggest the link between nutrition and COVID-19 is more about inflammation than any one food ingredient.

“In general, it makes sense as both coffee and vegetables have been linked to decreased inflammation and thus better immune function,” said Dr. Purvi Parikh, an adult and pediatric allergist and immunologist in New York City who’s a spokesperson for the Allergy & Asthma Network.

“While mechanism is not known, it further confirms healthier lifestyles are linked to better outcomes from COVID, as those who were obese, had heart disease, or diabetes did much worse than those who didn’t have those conditions,” Parikh told Healthline.

Further, Christina Meyer-Jax, MS, RDN, LDN, CLT, RYT, a health advisor for Lifesum and Gympass, said the new research once again reveals that people who are breastfed as infants, have diets higher in plant-based foods, and eat less processed meats and junk foods have a better chance against both acute and chronic diseases.

“Overall, this is a positive for eating more whole foods and plant-based when possible, but more research on diet and COVID-19 risk is needed to make strong dietary recommendations,” Meyer-Jax told Healthline.

Parikh said that while eating healthy can help prevent contributing factors for diseases such as obesity, diabetes, and heart disease, “good diet alone is not enough and a vaccine is the single most effective way to prevent COVID-19.”

Here’s a look at some benefits for the foods highlighted in the study:


While both tea and coffee support your immune system and have disease-fighting chemical compounds, Meyer-Jax said coffee has more polyphenols than tea, specifically chlorogenic acid, which is a unique compound in coffee.

“Other studies have shown that this compound may support immune function,” she noted.

Meyer-Jax said more research needs to be done to show what may be directly affecting these outcomes and what caffeine intake would be considered a safe level.


Vegetables contain powerful micronutrients and phytonutrients that synergistically help support immune function, explained Meyer-Jax.

“Vegetables also contain fiber, which research has shown relates to a better gut bacteria mix,” she said.

“Having more ‘good for you’ gut bacteria can lead to a stronger immune system and less inflammation, resulting in better overall health,” she added.

Breast milk

Health experts have reported for years that breast milk provides antibodies that can help infants with ailments such as ear infections, colds, flu, and gut infections.

They have also noted that breastfed babies have extra protection against respiratory tract infections. The coronavirus would fall into this category.

Research done earlier this year also concluded that people who have been vaccinated can pass on the protective benefits of the vaccine to infants via breast milk.

There are lots of foods that can contribute to a healthy immune system beyond coffee, vegetables, and breast milk.

Experts note that it’s up to the individual and their household to determine which foods are kept on hand.

They said you ultimately have the power to make positive changes for your immune system to help prevent diseases of all kinds — including COVID-19.

Making nutritional changes that are sustainable needs to come from a place of being realistic, said Meyer-Jax.

“It’s a gradual process of adding in one good habit at a time, sticking to that, and then building in new habits from there,” she said.

“Having support is also key,” she added. “I recommend to my clients to use healthy eating apps… to help them set realistic health goals and give them tools such as meal plans and diet tracking to achieve them.”