COVID-19 Defense: Antiviral Power with Plant-Based Diets

A plant-based or vegetarian diet is associated with a 39% decreased risk of COVID-19 infection, according to research published in the open-access journal BMJ Nutrition Prevention & Health.

According to the findings, a diet heavy in vegetables, beans, and nuts and low in dairy products and meat may help to stave off the infection.

Several studies have revealed that nutrition may play a significant role in the progression of COVID-19 infection, as well as the factors that increase the risk of its associated consequences.

As a result, the researchers set out to assess the possible impact of dietary patterns on the incidence, severity, and duration of COVID-19 infection in 702 adult volunteers recruited between March and July 2022.

Participants were asked about their regular eating habits and food group frequency, as well as their lifestyle and medical history, including COVID-19 vaccination. They were then classified as either omnivore (424) or predominantly plant-based (278).

The plant-based food category was further subdivided into flexitarians/semi-vegetarians (87), vegetarians and vegans (191).

Those who reported eating mostly plant-based or vegetarian diets consumed more vegetables, legumes, and nuts and consumed less/no dairy and meat.

There were no significant differences between the omnivorous and plant-based groups in terms of sex, age, or immunization uptake. However, a much greater number of people had received postgraduate education in the latter.

Omnivores also had a greater risk of medical issues and less physical activity. Furthermore, the incidence of overweight and obesity was considerably greater among omnivores–all of which are related with a higher risk of COVID-19 infection and more severe symptoms/complications.

In all, 330 patients (47%) reported having COVID-19 infection. 224 (32%) had mild symptoms, while 106 (15%) reported moderate to severe symptoms.

The reported incidence of COVID-19 was much greater in omnivores than in plant-based dietary groups: 52% versus 40%. They were also more likely to have had a moderate to severe infection: 18% vs. slightly more than 11%.

However, there was no change in the duration of symptoms.

There was no overall difference in symptom severity between the omnivore and plant-based dietary groups after accounting for potentially important factors such as weight, pre-existing medical problems, and physical activity levels.

Those who ate a largely plant-based or vegetarian/vegan diet, on the other hand, were 39% less likely to become infected than omnivores.

As an explanation for their findings, they speculate that largely plant-based diets contain more nutrients that stimulate the immune system and aid in the battle against viral infections.

“Plant-based dietary patterns are rich in antioxidants, phytosterols and polyphenols, which positively affect several cell types implicated in the immune function and exhibit direct antiviral properties,” they write.

However, because this is an observational study, it cannot identify causal factors. The researchers also admit that the study was based on personal recall and subjective assessment, both of which are open to error.

Nevertheless, they conclude: “In light of these findings and the findings of other studies, and because of the importance of identifying factors that can influence the incidence of COVID-19, we recommend the practice of following plant-based diets or vegetarian dietary patterns.”

“This research adds to the existing evidence, suggesting that diet may have a role in susceptibility to COVID-19 infection,” comments Shane McAuliffe, Senior Visiting Academic Associate, NNEdPro Global Institute for Food, Nutrition and Health, which co-owns BMJ Nutrition Prevention & Health with BMJ.

“But this remains an area of research that warrants more rigorous and high-quality investigation before any firm conclusions can be drawn about whether particular dietary patterns increase the risk of COVID-19 infection,” he adds.