food’s effects on COVID risk and severity

In more good COVID news that’s not exactly surprising, new research supports the idea that eating healthy helps keep you healthy.

A September 2021 study published in the journal Gut found that folks eating more plant-based foods had lower risk and lower severity of COVID-19. (Read the full text study or the more reader-friendly Harvard Health Letter synopsis.)

Researchers tracked data from nearly 600,000 people submitted via smartphone from the beginning of the pandemic through December 2020. Folks answered survey questions about their food choices and, if they got sick, their COVID symptoms and severity.

The surveys asked about 27 different foods and participants were asked to recall how often they’d had a full portion of each food.

Researchers considered a diet healthier if it included more plant-based foods — veggies, but also fruits and grains. Researchers also analyzed these results in terms of socioeconomic deprivation — which considers education, economic security, housing and neighborhood quality, health and standard of living.

Key findings:

  • Eating more plant-based foods lowered risk and severity of COVID 19.
  • Poor diet combined with socioeconomic deprivation lead to greater COVID-19 risk than for either factor alone
  • Improving diet was most helpful for folks with more socioeconomic deprivation

Here’s the big take home message from the study:

“The beneficial association of diet with COVID-19 risk seems particularly relevant among individuals living in areas of higher socioeconomic deprivation. Our models estimate that nearly a third of COVID-19 cases would have been prevented if one of two exposures (diet and deprivation) were not present.” — Diet quality and risk and severity of COVID-19: a prospective cohort study

why does diet help?

Improving food choices, especially emphasizing vegetables and clean proteins, simply gives the body more tools to function well. A varied diet with high-quality produce means a more diverse microbiome (itself an important player in immunity) and a wide array of vitamins, minerals and micronutrients. It may not be enough to keep you from getting sick, but it gives your body more resilience in the face of sickness or other stressors.

Authors of this study note that prior research has focused more on individual nutrients, as was the case in the zinc study I wrote about earlier. This whole-diet research may be limited, but it’s a start.

my thoughts

The results from this research reinforce basic ideas about the importance of nutrition. But of course the study has its limitations.

First, the research relies on recall of pre-pandemic diets and self-reported food choices. It’s well known that people can exaggerate their veggie intake when talking to healthcare workers, including researchers.

Also, the researchers acknowledge that participants were mostly white and living in areas of greater socioeconomic advantage. People who eat more veggies in general may also have other health-promoting behaviors dialed in.

Because these data are from earlier in the pandemic, the results address the original variants and cover a period before vaccines were available. I see no reason to believe more recent data would support different conclusions.

Based on my reading of the science and experience in practice, I continue to believe that clean animal protein is an important contributor to health. Researchers cite earlier studies showing the COVID-specific health benefits of a fish-and-veggies diet. These types of studies can’t distinguish between a burger at McDonald’s and grass-fed and -finished beef. That doesn’t mean wild and well-raised animals don’t support health — although these are beyond the financial reach of many.

go for good, not perfect

I want to reiterate that not everyone can eat a “perfect” diet — whatever that is. No shame for not being able to do everything!

Still, I find this kind of research hopeful and empowering, giving us some measure of control in a pretty out-of-control time. It’s a suggestion for affirmative steps folks can take to improve our odds.

After nearly two full years of the pandemic we know that diet alone isn’t always enough. But better is … better. Know that doing whatever you can do can help.

More reasons to eat the rainbow!




—Dr. Orna


P.S. Want help dialing in the best food choices to support your health? I’ve got telemedicine appointments open for folks living in Alaska and Oregon. Schedule here. If you’re in a different state, let me know. I can help you find resources that will work where you are.



Photo via @NappyStock.