Vegetarians, in general, tend to have reduced risks for common health problems, including obesity and ischemic heart disease. But new research has found a surprising twist: vegetarians may have a slightly higher risk of stroke compared to meat-eaters.
Analyzing diet
Researchers looked at the data from 48,188 people with an average age of 45. They followed the participants—who had no history of stroke or ischemic heart disease (IHD)—for an average of 18.1 years. They divided the group into three smaller groups:
- vegans and vegetarians (no meat or fish)
- pescatarians (fish but no meat)
- meat-eaters
(The vegans were grouped in with the vegetarians because there weren’t that many vegans in the study.)
The team collected information on blood pressure, BMI and height, as well as overall food intake and nutrient levels (using a food questionnaire). They found that:
- Compared to meat-eaters, pescatarians had a 13% lower rate of IHD.
- Compared to meat-eaters, vegetarians had a 20% lower rate of IHD.
This is likely due in part to the lower rates of diabetes and hypertension, and lower cholesterol and BMIs in those who don’t eat meat. But even after adjusting for these factors, the meat-eaters still had a “marginally significant” higher rate of IHD.
What was surprising, however, was that vegetarians had a 20% higher rate of hemorrhagic (not ischemic) stroke compared to meat-eaters. But why would vegetarians be more likely than meat-eaters to have a stroke? The researchers theorize that it could be that vegetarians have lower levels of other circulating nutrients in their bloodstream, including vitamin B-12, vitamin D and essential amino acids.
Limitations of the study
This study is by no means perfect and it’s important to note the following:
- The study was observational, so cause can’t be proved.
- The diets were self-reported, so there could be misreporting.
- Diet can change over days, weeks and years.
- The scientists didn’t have access to information about medications, such as statins, which could affect the results.
- Most of the participants were white and European.
