In a new study, researchers found vegetarian (including vegan) and pescetarian diets may be linked to a lower risk of coronary heart disease than diets that include meat.
But vegetarians and vegans had a 20% higher risk of stroke than meat-eaters, particularly hemorrhagic stroke (when blood from an artery starts bleeding into the brain).
This may be caused by low blood levels of total cholesterol or a low intake of certain vitamins.
The research was conducted by a team from the UK.
In recent years, more and more people have been turning to vegetarian and vegan diets, which is partly due to the perceived health benefits, as well as concerns about the environment and animal welfare.
But the full extent of the potential health benefits and hazards of these diets is not well understood.
Previous studies have suggested that vegetarians have a lower risk of CHD than non-vegetarians, but data from large studies are limited and little has been reported on the difference in risk of stroke.
In the study, the team explores the risks of coronary heart disease and stroke in meat eaters, pescetarians (those who eat some fish but not meat) and vegetarians over an 18 year period.
They examined 48,188 people (average age 45 years) who were recruited between 1993-2001, and had no history of heart disease or stroke.
The results showed that pescetarians and vegetarians had a 13% and 22% lower risk of heart disease than meat-eaters, respectively.
The difference may be at least partly due to lower BMI and lower rates of high blood pressure, high blood cholesterol and diabetes linked to these diets.
However, vegetarians and vegans had a 20% higher risk of stroke than meat-eaters, mainly due to a higher rate of hemorrhagic stroke.
Vegetarians and vegans in the study had lower circulating cholesterol and levels of several nutrients than meat-eaters (e.g. vitamin B12), which could explain these findings.
The team says this is an observational study, and as such, can’t establish a cause. And the findings may not be widely applicable because they were mainly based on white Europeans.
The study had a large sample size and long-term monitoring, but further research is needed to replicate the results in other populations and it should include further measurements of nutritional factors.
The lead author of the study is Dr. Tammy Tong.
The study is published in The BMJ.
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