A diet high in vegetables, legumes and nuts and low in dairy and meat is associated with a 39% lower chance of developing Covid-19, according to research published in the open access journal ‘BMJ Nutrition Prevention & Health’.

The survey was conducted on 702 adults in the period March-July 2022. Participants were asked about their usual eating habits and the frequency with which they consumed food groups, as well as their lifestyle and medical history. They were then divided into groups: omnivorous or mainly plant-based. The plant-based diet group was further divided into those who ate meat three or fewer times a week and vegetarians and vegans.

There were no significant differences in age and gender between the two groups. However, omnivores reported a higher rate of medical conditions and lower rates of physical activity, and the overweight and obese were also more common in this group, all factors associated with a higher risk of Covid-19 infection and more severe symptoms.

In total, 330 people said they had contracted Covid-19, of which 224 said they had mild symptoms and 106 moderate to severe symptoms. Omnivores had a significantly higher reported incidence of Covid-19 than plant-based groups (52% vs. 40%). In addition, they were more likely to have a moderate to severe infection, 18% versus 11%. There was, however, no difference in how long symptoms lasted.

After accounting for potentially influencing factors such as weight, pre-existing medical conditions and physical activity levels, the researchers found that those who more often followed a vegetarian and vegan diet were 39% less likely to be infected than omnivores. In contrast, they found no difference in symptom severity between the omnivore and vegetarian diet groups.

The researchers suggest as an explanation for their findings that a mostly vegetarian diet might provide more nutrients that boost the immune system and help fight viral infections. “Plant-based dietary patterns are rich in antioxidants, phytosterols and polyphenols, which positively affect various cell types, which are involved in the functioning of the immune system and exhibit direct antiviral properties,” they note.

However, they emphasize that this is an observational study and therefore cannot establish causal factors. They conclude, however, that in light of these findings and the findings of other studies, vegetarian dietary patterns are recommended.

*Link to the scientific publication