Vegetarian and vegan diets may be linked to a lower risk of heart disease, but experts now say they could increase the risk of a stroke.
Researchers at the University of Oxford say the increased risk of stroke could be in part due to a lack of vitamins.
The study, which featured in the British Medical Journal, used data from more than 48,000 people, who had no history of heart disease or stroke, and who were split into three groups: meat-eaters, pescatarians (those who do not eat meat but do eat fish) and vegetarians and vegans.
After 18 years, data showed that there were 2,820 cases of heart disease and 1,072 cases of strokes.
Once the results were adjusted, pescatarians recorded a 13% reduced risk of heart disease than meat eaters, with people on plant-based diets showing a 22% lower risk – the equivalent of 10 fewer cases in vegetarians and vegans than in meat eaters per 1,000 people over 10 years.
The researchers said: “We observed lower rates of ischaemic heart disease in fish eaters and vegetarians than in meat eaters, which appears to be at least partly due to lower body mass index and lower rates of high blood pressure, high blood cholesterol, diabetes associated with these diets.”
Despite the reduced heart disease risk, the stroke rate in non-meat and fish eaters was 20% higher than those who did eat meat, which is three more stroke cases per 1,000 people over 10 years – which the researchers said could be down to the lower levels of vitamins consumed by non-meat eaters.
Researchers admitted that more studies were needed to be sure of the nutritional factors as well as suggesting that low blood levels of total cholesterol among vegetarians and vegans may also play a role.
Tracy Parker, senior dietitian at the British Heart Foundation, said: “Whilst this is an interesting finding, this study is observational and doesn’t provide us with enough evidence, so more research in this area would be needed.”
Vegetarian and vegan diets may be linked to a lower risk of heart disease, but experts now say they could increase the risk of a stroke. Researchers at the University of Oxford say the increased risk of stroke could be in part due to a lack of vitamins.