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2023 Namey/Burnett Preventive Medicine Writing Award third-place winner Violeta Foss, OMS-III. reviews and advocates for plant-based nutrition in the fight against COVID-19.
Violeta Foss, OMS-IIISponsored by the ACOFP Foundation, with winners selected by the ACOFP Health & Wellness Committee, the Namey/Burnett Preventive Medicine Writing Award honors the memory of Joseph J. Namey, DO, FACOFP, and John H. Burnett, DO, FACOFP—dedicated advocates for osteopathic medicine—and recognizes the best preventive medicine blog posts submitted by osteopathic family medicine students and residents.
“An apple a day keeps the doctor away.” The nineteenth-century English-language proverb remains popular to this day, suggesting that a healthy diet can save us frequent visits to the doctor.1 Does this saying hold more truth than we thought?
According to the American Heart Association, the term “Mediterranean diet” encompasses eating habits that emphasize a plethora of fruits, vegetables, grains, nuts, and seeds, with low to moderate amounts of dairy products, eggs, fish, and poultry.2 Populations following the Mediterranean diet largely use minimally-processed plant-based based foods as a source of nutrition. The American Heart Association recommends the Mediterranean diet as a way to reduce the risk for common conditions that may lead to disability, including heart disease, stroke, diabetes, high blood pressure, and high cholesterol.2 A plant-based diet that excludes all animal products may offer even more health benefits such as potentially reversing heart disease.3 In recent years, plant-based or plant-exclusive diets have been gaining recognition as powerful tools against disease, including COVID-19.
The COVID-19 pandemic has highlighted the need for primary, secondary, and tertiary prevention of chronic disease prior to or after a viral infection. Chronic conditions are a leading cause of death and disability in the United States and are responsible for $4.1 trillion in healthcare costs each year.4 When COVID-19 emerged, populations living with chronic disease were among the most vulnerable, prone to severe illness and even death, contributing to the enormous strain placed on American healthcare.5,6
Three years since the first reported COVID-19 cases, antiviral treatment options and vaccines remain effective against severe illness and death.7,8 Yet, the novel disease has led to a multitude of disabling long-term symptoms for many individuals.9 According to the National Center for Health Statistics, 14.6% of all adults in the United States have experienced persistent COVID-19 symptoms, lasting weeks to months after initial recovery and reducing their ability to carry out activities of daily living.9,10
Recognizing new prevention strategies will be crucial in the ongoing battle against COVID-19, its multiple variants, post-COVID conditions, growing list of symptoms, and overall burden of disease. This review aims to present the available literature on the relationship between plant-based diets and COVID-19. While studies on the association between diet and COVID-19 incidence and severity are limited, the literature suggests a possible protective effect of plant-based nutrition.
PubMed was used as a search engine to identify current literature on diet and COVID-19 with the following keywords: “SARS-CoV-2,” “COVID-19,” “plant-based diet,” “Mediterranean diet,” and “vegetarian.” Inclusion criteria included all articles published between 2020 and 2022 that had the abstract, full text, or both available in English. Exclusion criteria included review articles, as well as studies that did not explore the relationship between diet and COVID-19, which was determined by evaluating each individual article for relevance with respect to this review.
The initial keyword search retrieved 35 articles. After inclusion and exclusion criteria were applied, only 6 articles were deemed relevant to the topic of plant-based nutrition and its impact on COVID-19 burden of disease. The notable results from each study are summarized in Table 1: Studies Evaluating the Relationship between Dietary Habits and COVID-19.11-16 Overall limitations include sample size, study duration, possible geographic bias, and survey reporting bias.
COVID-19 is still a novel disease and much remains to be discovered about the precise way the virus infects cells, causing varying degrees of illness across populations. Studies suggest that the course of the disease is closely tied to an individual’s inflammatory response.17 Dysregulated levels of proinflammatory mediators, including cytokines and chemokines, cause a cascade of changes to the homeostatic state, leading to disease progression and worsening illness severity.18,19 When the aberrant immune response persists after initial recovery, individuals experience post-COVID symptoms, also known as long COVID.20
While plant-based nutrition is a developing field, the interest in such dietary patterns has been growing. Proteins, antioxidants, and sterols contained in whole-food plant-based sources have demonstrated anti-inflammatory effects.21 Various studies suggest that individuals following low-fat, vegetarian diets have a decreased risk for heart disease and diabetes, as well as chronic disease reversal.3,21 Plant-source nutrients are thought to exert their beneficial effect on these non-communicable diseases, which share a pathophysiology rooted in chronic inflammation.21
The areas of the world known for the particularly extended longevity of their populations, known as “Blue Zones,” follow a predominantly plant-based diet, with no processed food or red meat consumption.22 Interestingly, the Blue Zones do not only see low prevalence of chronic disease, but have also shown minimal COVID-19 mortality, implying a possible association between diet and severe illness prevention.22 Considering the suggested role of inflammation in the pathophysiology of COVID-19, plant-based nutrition may be used as a tool to aid the body’s immune response and mitigate the effects of COVID-19.
Overall, current literature agrees that plant-based nutrition may be an effective way to approach the prevention of COVID-19 and its sequelae. The evaluated studies concur that an association exists between diet and illness severity. Further research is needed to determine if plant-based diets impact the incidence and course of COVID-19 directly or indirectly, by alleviating the underlying conditions that predispose individuals to severe illness. The results and information about the individual studies are summarized in Table 1.
Several studies found evidence that adhering to a plant-based diet was associated with a lower risk of severe COVID-19 illness.11,12,13,16 The data suggest that acquiring daily nutrition from predominantly plant sources may be linked to lower incidence of COVID-19, likely due to a strengthened immune system.11,14,15 When compared to a pescatarian diet, exclusively plant-based diets showed lower odds of experiencing moderate to severe COVID-19.12 Existing research, though still limited, points to the beneficial effects of a plant-based diet, especially as we learn more about the processes underlying disease severity.
COVID-19 has changed the healthcare landscape and emphasized the increasing need for disease prevention. As lifestyle medicine gains popularity as a tool to achieve health, osteopathic family physicians can use existing research to help patients better understand and adopt dietary changes. Nutrition can be used as another safe preventative strategy to mitigate the impact of COVID-19 in the wake of the pandemic. Whole-food plant-based diets may be an important adjunct to pharmacologic therapies and vaccines, conferring unique protection and enhancing the body’s self-healing mechanisms. In the constant quest for preventing disease and improving health, nutrition can provide osteopathic family physicians with another avenue to advocate for their patients and help relieve the vast burden of COVID-19.
ACOFP is a community of current and future family physicians that champions osteopathic principles and supports its members by providing resources such as education, networking and advocacy, while putting patients first.