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Study Shows Plant-Based and Seafood Diets May Improve COVID-19 Outcomes

Throughout the second year of the global COVID-19 pandemic, public attention has primarily been focused on vaccination as the protocol for prevention, in addition to slowing the spread of the virus by wearing masks, contact tracing, testing, and lockdowns.

Now, additional hedges against severe COVID-19 symptoms may be as close as the next meal. “Plant-based and plant-based-pescatarian diets” may lower incidences of moderate to severe COVID-19, according to a peer-reviewed study published earlier in 2021. The study, published in the journal BMJ Nutrition, Prevention & Health in June 2021, describes itself as the first to have “investigated the association between dietary patterns and COVID-19.”

Pico de gallo, a colorful plant-based Mexican recipe. ©Jeffrey W/Wikimedia Commons
Pico de gallo, a colorful plant-based Mexican recipe. ©Jeffrey W/Wikimedia Commons

Plant-based (vegetarian) diets are high in foods such as vegetables, legumes, and nuts, and low in poultry, red meat, fish, and processed meats. Such a diet has plentiful nutrients, especially phytochemicals. Plant-based pescatarian diets are similar, with the addition of fish as a source of protein.

Healthcare Workers Surveyed on Diet and COVID-19 Symptoms

Frontline healthcare workers with a high frequency of exposure to COVID-19 patients in France, Germany, Italy, Spain, the United Kingdom, and the United States were surveyed between July and September 2020. The 2,884 participants provided information on demographic characteristics, past medical histories, medications, lifestyle, diet, and COVID-19 status and symptoms.

Lox on rye bread with avocado and lemon. ©twenty20photos/envato
Lox on rye bread. ©twenty20photos/envato

COVID-19 cases, whether symptomatic or asymptomatic, were self-reported by participants as Very Mild, Mild, Moderate, Severe, or Critical, with specific criteria for symptoms within each category.

Participants who reported following a “plant-based diet” and a “plant-based or plant-based-pescatarian diet” had 73% and 59% lower odds, respectively, of contracting moderate to severe COVID-19 compared with those who did not follow those dietary patterns. These associations held true when weight and coexisting medical conditions were factored in.

No association was found between diet and either the risk of contracting COVID-19 or the length of the illness.

“The trends in this study are limited by study size (small numbers with a confirmed positive test) and design (self-reporting on diet and symptoms), so caution is needed in the interpretation of the findings,” said Shane McAuliffe, deputy chair of The Need For Nutrition Education/Innovation Programme (NNEdPro) Nutrition and COVID-19 Taskforce. “However, a high-quality diet is important for mounting an adequate immune response, which in turn can influence susceptibility to infection and its severity.”

The Unique Protection Offered By Plant-Based‌ Diets‌

Plant-based eating as a lifestyle has already been shown to provide benefits for a multitude of ailments. Documentaries such as Forks Over Knives, Earthlings, and PlantPure Nation have brought the benefits of vegetarian diets to the forefront, backed by a plethora of research. In a 2019 study in the Journal of the American Heart Association, Johns Hopkins University researchers reported that, in a thirty-year period, people eating a mostly plant-based diet were 32% less likely to die from a cardiovascular condition and 25% less likely to die from any cause. A 2017 report published in International Journal of Epidemiology suggested that eating at least 500 grams of fruit and 800 grams of vegetables per day is associated with a reduced risk of many chronic diseases.

The benefits of plant-based diets come from the fact that they are replete with nutrients, especially phytochemicals, fiber, and essential vitamins and minerals. Previous studies have reported that these nutrients, specifically vitamins A, C, D, and E, decreased the risk and shortened the duration of the common cold, pneumonia, and other respiratory infections such as COVID-19.

Pescatarian-friendly Peruvian ceviche ©lblinova/Envato
Pescatarian-friendly Peruvian ceviche. ©lblinova/envato

Pescatarian diets offer unique benefits because fish is a source of vitamin D and Omega-3 fatty acids (EPA and DHA). Intake of Omega-3s provides anti-inflammatory effects and suppresses the production of pro-inflammatory cytokines, among other benefits, providing more favorable outcomes for patients with acute respiratory distress syndrome. While the 2021 BMJ Nutrition, Prevention & Health study showed evidence that fish intake can have favorable impacts on respiratory illness, future research is needed to confirm this association specifically to COVID-19.

Fortify Your Plant-Based Diet By Eating a Variety of Colors

Putting a plant-based diet in place is as simple as eating fruits and vegetables in a rainbow of vibrant colors. This ensures the consumption of a variety of phytochemicals, vitamins, minerals, and antioxidants. The U.S. federal Office of Disease Prevention and Health Promotion recommends consuming two and one-half cups of vegetables and two cups of fruit each day. Lisa McDowell, director of lifestyle medicine and clinical nutrition at Saint Joseph Mercy Health System in Ann Arbor, Michigan, suggests including “deeply pigmented fruits and veggies in at least five different colors.” This ensures getting all the micronutrients, which work synergistically.

It is not necessary to eat five colors per day; the goal is to include a couple of different foods from each of the following color groups through the week. Infographics and charts are available for download from the American Heart Association, Vegan Easy, and other nutrition-centric organizations. Apps such as Eat the Rainbow Food Journal, Eat Five, and VegHunter also help to track vegetable and fruit intake.

While it’s not necessary to eat five colors per day, try to include a couple different foods from each of the following color groups throughout the week.
  1. Green: Dark greens contain folate for healthy cells and calcium for stronger bones, muscles, and heart regulation. Get plenty of asparagus, avocados, broccoli, Brussels sprouts, green tea, kale, kiwi, spinach, and green herbs.

  2. Blue and purple: Anthocyanins wipe out free radicals, reduce inflammation, and boost brain health. Resveratrol can delay cellular aging, protect the heart, and reduce the risk of cancers. Blueberries, blackberries, eggplant, elderberries, figs, grapes, plums, raisins, eggplant, and purple cabbage are good choices.

  3. Red: Rich in lycopene, a potent scavenger of gene-damaging free radicals, red plants boost heart, brain, eye, and bone health and reduce cancer risk. Try apples, beets, cherries, cranberries, raspberries, red peppers, tomatoes, and watermelons.

  4. Yellow and orange: Contains vitamin C, hesperidin, and carotenoids such as beta-carotene to boost the immune system, detoxify the body, reduce inflammation, and protect the heart. Add apricots, bananas, cantaloupe, carrots, mango, oranges, pineapple, pumpkin, sweet potatoes, tangerines, and yellow peppers.

  5. White and brown: The onion family contains allicin and beta glucans, which can help lower cholesterol. Nuts contain healthy fats. Other foods in this group contain blood pressure-regulating potassium and antioxidant flavonoids like quercetin and kaempferol. Choose beans, cauliflower, garlic, leeks, mushrooms, nuts, onions, parsnips, and whole grains.

Meal Prep Makes Switching to a Healthier Diet Easier

William Li, M.D., author of Eat to Beat Disease, advises people to “practice health care at home every day in our own kitchens.” But breaking old habits and incorporating new ones isn’t always simple. For those with busy schedules, meal prepping can make switching to a new way of eating easier. Sites such as She Likes Food, Sweet Peas and Saffron, Running in a Skirt, and Budget Bytes focus on recipes and time-saving tips to prepare a week’s worth of healthful meals.

Prepping meals ahead of time can support healthier food decisions. ©Ella Olsson/Pexels
Prepping meals ahead of time can support healthier food decisions. ©Ella Olsson/Pexels

Where is the Media Attention on Diet and COVID-19?

While plant-based and plant-based-pescatarian diets appear to cultivate a compelling defense against the likelihood of suffering severe COVID-19 symptoms, the mainstream news has continued to focus primarily on the medical and political issues of the pandemic. Rates of vaccination, infection, hospitalization, and death fill the news reports.

Sadly, the angle of how eating a healthy, plant-based diet as a way to fend off COVID-19 has yet to be properly covered. However, as many functional medical practitioners and nutritionists are saying, the story of one’s future with COVID-19 may be written by the food on one’s plate.

Further studies are needed to confirm the findings, but, for now, the authors of the June 2021 study conclude, “Our results suggest that a healthy diet rich in nutrient-dense foods may be considered for protection against severe COVID-19.”


*Julie Peterson is a freelance journalist based in the Midwest region of the U.S., who has written hundreds of articles on natural approaches to health, environmental issues, and sustainable living.


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