Eating a plant-based or fish-based diet may help reduce your chances of developing moderate to severe Covid-19, according to a new study.

Following a plant-based diet was associated with 73% lower odds of severe disease, while a pescatarian diet was linked to 59% reduced odds.

“Our results suggest that a healthy diet rich in nutrient dense foods may be considered for protection against severe Covid-19,” researchers said.

However other experts have urged caution interpreting the findings. So don’t go ditching the masks and scrapping social distancing because you eat a lot of vegetables.

What did the study involve?

For the study in the BMJ Nutrition, Prevention and Health Journal, researchers drew on the survey responses of 2,884 frontline doctors and nurses with extensive exposure to the virus, working in France, Germany, Italy, Spain, the UK and the US.

The survey, which ran between July and September 2020, asked for detailed information about dietary patterns, the severity of any Covid-19 infections they’d had, personal background, medical history, medication use and lifestyle.

The various diets were categorised into:

• plant-based diets, which are higher in vegetables, legumes and nuts

• pescatarian, which are the same as plant-based diets, but with added fish/seafood

• and low carb, high protein diets which included meat

What were the results?

Some 568 respondents said they’d experienced symptoms consistent with Covid-19 infection or they’d had no symptoms but had a positive swab test for the infection. Of these, 138 said they’d had moderate to severe Covid-19 and the remaining 430 said they’d had mild infection.

After factoring in several potentially influential variables like age, ethnicity, and lifestyle, respondents who said they ate plant-based diets’ or plant-based/pescatarian diets had, respectively, 73% and 59% lower odds of moderate to severe Covid-19 infection than those who didn’t have these dietary patterns.

Those who said they ate a low carb, high protein diet had nearly four times the odds of moderate to severe Covid-19 infection compared to those who ate a plant-based diet.

The study is observational, and so can’t establish cause, but researchers pointed out that plant-based diets are rich in nutrients, especially phytochemicals (polyphenols, carotenoids), vitamins and minerals, all of which are important for a healthy immune system.

Meanwhile, fish is an important source of vitamin D and omega-3 fatty acids, both of which have anti-inflammatory properties.

Deputy chair of the NNEdPro Nutrition and Covid-19 Taskforce, Shane McAuliffe, said caution is needed in interpreting the findings, however he added that a high quality diet is “important for mounting an adequate immune response, which in turn can influence susceptibility to infection and its severity”.