In a recent study led by researchers at Massachusetts General Hospital (MGH) and published in Gut, people whose diets were based on healthy plant-based foods had lower risks of becoming infected COVID-19 and experiencing serious symptoms.
“Previous reports suggest that poor nutrition is a common feature among groups disproportionately affected by the pandemic, but data on the association between diet and COVID-19 risk and severity are lacking,” says lead author Jordi Merino, PhD, Research Associate at the Diabetes Unit and Center for Genomic Medicine at MGH and an instructor in medicine at Harvard Medical School.
For the study, Merino and his colleagues examined data on 592,571 participants of the smartphone-based COVID-19 Symptom Study. Participants lived in the United Kingdom and the United States, and they were recruited from March 24, 2020, and followed until December 2, 2020. At the start of the study, participants completed a questionnaire that asked about their dietary habits before the pandemic. Diet quality was assessed using a healthful Plant-Based Diet Score that emphasizes healthy plant foods such as fruits and vegetables.
During follow-up, 31,831 participants developed COVID-19. Compared with individuals in the lowest quartile of the diet score, those in the highest quartile had a 9% lower risk of developing COVID-19 and a 41% lower risk of developing severe COVID-19. “These findings were consistent across a range of sensitivity analysis accounting for other healthy behaviors, social determinants of health and community virus transmission rates,” says Merino.
The researchers also found a synergistic relationship between poor diet and increased socioeconomic deprivation with COVID-19 risk that was higher than the sum of the risk associated with each factor alone.
“Our models estimate that nearly a third of COVID-19 cases would have been prevented if one of two exposures — diet or deprivation — were not present,” says Merino.