Plant-based and pescatarian diets may lower odds for severe COVID-19

Frontline physicians and nurses who consumed plant-based or pescatarian diets had lower odds of developing moderate-to-severe COVID-19, a case-control study showed.

“While [health care workers (HCWs)] are being vaccinated in many countries currently, with the emergence of new variants and challenges in accessing COVID-19 vaccines globally, understanding risk factors associated with COVID-19 susceptibility and disease course in physicians and nurses may help to develop supportive strategies for protecting these workers both now and in the future,” Hyunju Kim, PhD, an assistant scientist in the department of epidemiology at the Johns Hopkins Bloomberg School of Public Health, and colleagues wrote.

The researchers analyzed survey responses from 2,884 physicians and nurses in France, Germany, Italy, Spain, the United Kingdom and the United States who had substantial exposure to patients with COVID-19 (eg, those who identified themselves as internists, ED or critical care physicians, worked in an ICU and/or critical care unit, had the presence of COVID-19 symptoms and a COVID-19 test result). The survey was conducted from July 17 to Sept. 25, 2020. Of the HCWs, 568 had COVID-19 — 138 were considered moderate-to-severe cases — and the remaining participants served as controls.

The results, published in BMJ Nutrition, Prevention and Health, showed that after adjusting for demographic data, smoking, physical activity, BMI and medical history, the physicians and nurses who indicated that they followed a plant-based diet or pescatarian diet had 73% (OR = 0.27; 95% CI, 0.1-0.81) and 59% (OR = 0.41; 95% CI, 0.17-0.99) lower odds of moderate-to-severe COVID-19 severity, respectively, compared with the HCWs who stated that they did not follow these diets. Compared with the HCWs who said they followed plant-based diets, those who indicated that they consumed low-carbohydrate, high-protein diets had greater odds of moderate-to-severe COVID-19 (OR = 3.86; 95% CI, 1.13-13.24). No links were found between self-reported diets and COVID-19 infection or duration.

“Interestingly, when we restricted cases to those with a positive [polymerase chain reaction] or antibody test, individuals who reported following plant-based diets or pescatarian diets had lower odds of COVID-19 infection,” Kim and colleagues wrote.

The researchers suggested that plant-based diets are rich in nutrients — “specifically vitamins A, C, D and E” — which support the immune system and may have protected physicians and nurses against respiratory infection. Similarly, “pescatarian diets lie within the spectrum of plant-based diets” and are “an important source of vitamin D and omega-3 fatty acids,” which have “have anti-inflammatory effects.” Specifically, omega-3 has been shown to increase favorable outcomes in patients with acute respiratory distress syndrome, they wrote.

Kim and colleagues said “future studies with detailed macro- and micronutrient data are warranted to study associations between dietary intake and COVID-19 severity.”