Scientists reviewed seven prospective studies involving more than 250,000 people and found that after adjusting for various stroke risks and for other nutrients consumed, those who had the highest consumption of protein had a 20 percent decreased risk for stroke compared with those with the lowest.
Each increase of 20 grams per day in protein — about the amount in a 3-ounce serving of chicken or fish or a cup of beans — was associated with a 26 percent decrease in risk, a dose-response relationship that further strengthens the association.
The finding does not apply to red meat, which has been shown to increase the risk for stroke and was not evaluated in the studies reviewed.
Some evidence suggested that animal protein was slightly more effective than vegetable protein, although there was not enough data on vegetable consumption to reach a definitive conclusion about the exact difference.
“Moderate dietary protein intake may lower the risk of stroke,” said the senior author, Dr. Xinfeng Liu, a neurologist at the Nanjing University School of Medicine in China. “This does not mean that people should avoid red meat entirely,” he added, but “increasing intake of fish or vegetables is recommended.”