Alternatively, those eating poorer quality diets were more at risk, a finding that was amplified for those living in a more socioeconomically deprived area.
Researchers analyzed data from 592,571 ZOE COVID Study app contributors in the U.S. and U.K., who completed a survey about the food they ate during February 2020. Rather than look at specific foods or nutrients, the survey looked at broader dietary patterns, and produced a ‘diet quality score’ that reflected the overall merit of each person’s diet. Diets with high quality scores were found to contain plant-based foods such as fruits, vegetables, whole grains, and nuts, as well as oily fish, healthier fats, and less processed foods or refined carbohydrates. High quality diet scores were also linked with a healthier and more diverse microbiome.
“These findings chime with recent results from our landmark PREDICT study, showing that people who eat higher quality diets (with low levels of ultra-processed foods) also have a healthier collection of microbes in their guts, which is linked to better health,” said Professor Tim Spector, lead scientist at ZOE COVID Study and professor of genetic epidemiology at King’s College London, in the press release. “You don’t have to go vegan, but getting more diverse plants on your plate is a great way to boost the health of your gut microbiome, improve your immunity and overall health, and potentially reduce your risk from COVID-19.”
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The numbers: People with the highest quality diet were around 10% less likely to develop COVID-19 than those with the lowest quality diet, and 40% less likely to become severely ill. The scale of the study allowed researchers to adjust for multiple confounding factors, and this effect was independent of other risk factors including age, weight, race, ethnicity, and underlying health conditions, but social inequality worsened outcomes; specifically, those in low-income neighborhoods who ate the lowest quality diet were around 25% more at risk from COVID-19 than people who ate the same way, but lived in affluent neighborhoods.Based on these results, researchers estimate that nearly a quarter of COVID-19 cases could have been prevented if these differences in diet quality and socioeconomic status had not existed.
“For the first time we’ve been able to show that a healthier diet can cut the chances of catching COVID-19, especially for people living in the poorest areas,” said Dr. Sarah Berry, study co-lead and associate professor in nutritional sciences at King’s College London, in the press release. “Access to healthier food is important to everyone in society, but our findings tell us that helping those living in more deprived areas to eat more healthily could have the biggest public health benefits.”
Professor Andrew Chan MD, MPH, gastroenterologist and director of epidemiology at Massachusetts General Hospital, and professor at Harvard Medical School, added: “Diet quality is an established risk factor for many conditions that are known to have an inflammatory basis. Our study demonstrates that this may also hold true for COVID-19, a virus which is known to provoke a severe inflammatory response. We also highlight how diet quality is also an important social determinant of health. COVID-19 has laid bare how such social determinants underlie the severe racial and socioeconomic disparities in COVID-19 risk that we and others have documented.”
