Vegetarians are 73 per cent less likely to get severe Covid-19 than their meat-eating peers, a new study claims.
Self-declared pescetarians were also found to be at 59 per cent less at risk than someone who regularly consumes red meat or poultry.
Low-carbohydrate, high-protein diets also appeared to be linked to a 3.8 times increased chance of getting moderate to severe illness.
The research, published in BMJ Nutrition, Prevention and Health, examined data from 2,884 healthcare workers across six countries including the UK. More than 2,300 did not catch Covid-19 and 568 did.
Among those who had Covid-19, 138 reported moderate to severe symptoms and 430 had mild or very mild illness.
Participants were asked to think about the diet they had in the year before Covid and were given 11 choices: whole foods, plant-based diet; keto diet; vegetarian diet; Mediterranean diet; pescatarian diet; Palaeolithic diet; low fat diet; low carbohydrate diet; high protein diet; other; none of the above.
Among the 568 participants who reported they had previously had Covid-19, 41 said they followed a plant-based diet and 46 said they followed a plant-based or pescatarian diet.
The researchers found that these 46 people each ate significantly less meat and dairy than other cohorts, but they still had 13 portions of dairy, two portions of egg, one poultry dish and two red meat meals a week, on average.
The authors, led by a team in the US, say: “In six countries, plant-based diets or pescatarian diets were associated with lower odds of moderate-to-severe Covid-19.
“These dietary patterns may be considered for protection against severe Covid-19.””
As part of their analysis, the researchers from Johns Hopkins University accounted for weight, BMI and pre-existing health conditions.
Dr Gunter Kuhnle, professor of nutrition and food science at the University of Reading, said: “The findings of the study are not surprising: people who follow a mainly plant-based diet or eat fish are often healthier when compared to a control group with a ‘normal’ diet.
“An interesting – and for some surprising – finding is the higher risk found in those following a low-carbohydrate diet.”
However, Dr Carmen Piernas, nutrition scientist at the University of Oxford, criticised the way the study was conducted and questioned the strength of the findings.
“Overall, this is methodologically weak and while it raises an interesting possibility that the severity of Covid-19 may be related to diet quality, a larger-scale population based study is needed to support these preliminary findings since the population studied here is unlikely to represent behaviours of the general population,” she said.
Prof Francois Balloux, director of the UCL Genetics Institute, UCL said: “further validation may be required to confirm a direct, causal between diet and Covid-19 illness severity.”