Vegetarian diet linked to lower stroke risk

People who eat a vegetarian diet rich in nuts, vegetables, and soy may have a lower risk of stroke than those who eat a diet that includes meat and fish, according to a new study published in the journal Neurology.

The study, led by Chin-Lon Lin, MD, of Tzu Chi University in Hualien, Taiwan, involved two groups of people from Buddhist communities in Taiwan where a vegetarian diet is encouraged, and smoking and drinking alcohol are discouraged. Approximately 30 percent of participants in both groups were vegetarians. Of the vegetarians, 25 percent were men. Researchers defined vegetarians as people who did not eat any meat or fish.

At the start of the study, the average age of all participants was 50 years old and none had experienced stroke. The first group of 5,050 people was followed for an average of six years. The second group of 8,302 people was followed for an average of nine years. Participants were given medical exams at the start of the study and asked about their diet.

Vegetarians ate more nuts, vegetables, and soy than non-vegetarians and consumed less dairy, the researchers said. Both groups consumed the same amount of eggs and fruit. Vegetarians ate more fiber and plant protein and ate less animal protein and fat.

The researchers then looked at a national database to determine the numbers of strokes participants had during the study. In the first group of 5,050 people, there were 54 strokes. For ischemic strokes, which are strokes where blood flow to part of the brain is blocked, there were three strokes among 1,424 vegetarians, or 0.21 percent, compared to 28 strokes among 3,626 non-vegetarians, or 0.77 percent. After adjusting for age, sex, smoking and health conditions like high blood pressure and diabetes, researchers found vegetarians in this group had a 74 percent lower risk of ischemic stroke than non-vegetarians.

In the second group of 8,302 people, there were 121 strokes. For both ischemic and hemorrhagic strokes, also called bleeding strokes, there were 24 strokes among 2,719 vegetarians, or 0.88 percent, compared to 97 strokes among 5,583 non-vegetarians, or 1.73 percent. After adjusting for other factors, researchers found vegetarians in this group had a 48 percent lower risk of overall stroke than non-vegetarians, a 60 percent lower risk of ischemic stroke, and a 65 percent lower risk of hemorrhagic stroke.

One limitation of the study was that the diet of participants was only assessed at the start of the study, so it is not known if participants' diets changed over time. Study participants did not drink or smoke, so results may not reflect the general population. Results from the study population in Taiwan may not be generalizable worldwide. Finally, there could be other factors, not accounted for, that might affect stroke risk, the researchers said.

"Overall, our study found that a vegetarian diet was beneficial and reduced the risk of ischemic stroke even after adjusting for known risk factors like blood pressure, blood glucose levels and fats in the blood," said Lin in a statement. "This could mean that perhaps there is some other protective mechanism that may protecting those who eat a vegetarian diet from stroke."