Plant-Based and Pescatarian Diets May Protect Against Severity of COVID-19 Infection

by | Jan 27, 2022 | 2021, COVID-19, Vegetarianism

Written by Taylor Woosley, Staff Writer. Study findings suggest following a plant-based diet resulted in a 73% lower chance of developing severe COVID-19 symptoms, while participants following a pescatarian diet experienced a 59% lower chance of developing severe symptoms.

COVID-19, a disease caused by SARS-CoV-2, results in a pathogenic condition that ranges from asymptomatic cases to life-threatening conditions 1. Common symptoms include cough, fever, fatigue, loss of taste or smell, muscle weakness, and in severe cases it may even result in respiratory failure 2. Previous research on COVID-19 suggests that the viral infection leads to a significant increase in inflammatory markers in the body, leading to an excessive host immune reaction, causing extensive tissue damage 3.  Many people affected with COVID-19 continue to report symptoms after the acute phase of the infection. The umbrella term “long-COVID” has emerged over the last few months to describe moderate to severe symptoms affecting different organs that may last weeks to months after the initial infection 4. As COVID-19 continues to pose as a global threat with massive loss of life and economic burden, it is important to find ways to lessen the severity of symptomatic responses 5.

One proposed method of reducing COVID-19 symptom severity is the adoption of a plant-based or pescatarian diet, which consists largely of fruits and vegetables with the main protein source being seafood and the absence of meat.  While only 2.4% of the general US population follows a plant-based diet, there is a growing interest towards increasing the intake of whole foods and following a healthier lifestyle 6. Researchers suggest a diet comprised of predominantly nutrient-dense vegetables, legumes and nuts may lead to a reduced intake in pro-inflammatory mediators 7. Cumulative evidence shows that following a plant-based diet results in lower rates of obesity, diabetes, and dysbiosis of the microbiome, which could contribute to lower levels of severe infection 8.

In this COVID-19 case-control study, researchers created a health survey that was distributed among health care workers in six countries in the Survey Healthcare Globus network, with the aim of identifying health care workers who had high levels of exposure and risk for COVID-19. Participants were screened based on exposure level, medical specialty, practice setting, presence of COVID-19 symptoms and a COVID-19 positive test result based on PCR or antibody. The participating health care workers were also asked to fill out a survey containing basic demographic characteristics, past medical history, lifestyle, COVID-19 symptoms and a 47-item food frequency questionnaire. A total of 2,884 health care workers were included in the study and divided into two groups, symptomatic and asymptomatic COVID-19 patients (n=568) or a control (n=2316).

COVID-19 positive participants were asked to rate their level of symptoms, ranging from extremely mild to severe, and the number of days they experienced symptoms. Additionally, all participants reported if they followed any specific diet over the last year before COVID-19, such as a plant-based diet, Mediterranean diet, low-fat diet, etc. At the end of the study, the results were as follows:

  • Participants following a plant-based (n=254) had 73% lower odds of moderate to severe COVID-19 symptoms compared to those not following a plant-based diet (OR 0.27, 95% CI 0.10 to 0.81).
  • Participants following a plant-based or pescatarian diet (n=294) had 59% lower odds of moderate to severe COVID-19 (OR 0.41, 95% CI 0.17 to 0.99) compared to those not following a plant-based or pescatarian diet.
  • Compared to those following a plant-based diet, participants who followed a low-carbohydrate, high-protein diet were associated with 48% greater odds of moderate to severe COVID-19 (OR 1.48, 95% CI 0.89 to 2.49).

In conclusion, following a plant-based or pescatarian diet may result in a lower chance of developing moderate to severe COVID-19 symptoms. The addition of whole foods such as vegetables, legumes, nuts, and clean sources of protein may provide a level of protection against long-haul symptoms. Study limitations include potential incorrect data interpretation by the participating health care workers, lack of participants experiencing severe COVID-19 symptoms, the lack of adequate female participants (the study was predominantly male physicians), and the potential room for error when adjusting for a number of confounding factors. Kim et al suggest further research should continue to observe the immense benefits a plant-focused diet may have on severe infection.

Source: Kim, Hyunju, Casey M. Rebholz, Sheila Hegde, Christine LaFiura, Madhunika Raghavan, John F. Lloyd, Susan Cheng, and Sara B. Seidelmann. “Plant-based diets, pescatarian diets and COVID-19 severity: a population-based case–control study in six countries.” BMJ Nutrition, Prevention & Health (2021): bmjnph-2021.

© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY. Published by BMJ.

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Posted January 27, 2022.

Taylor Woosley studied biology at Purdue University before becoming a 2016 graduate of Columbia College Chicago with a major in Writing. She currently resides in Glen Ellyn, IL.

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