Diets Rich in Protein May Lower Stroke Risk
Study found lean animal proteins like fish showed most benefit
The results, which are published online June 11 in the journal Neurology, accounted for other factors that could affect the risk of stroke, such as smoking and high cholesterol, the study authors said.
The investigators found in their analysis that animal protein reduced stroke risk by 29 percent, while vegetable protein lowered risk about 12 percent. However, the study only found an association between protein intake and stroke risk because it was not designed to prove a cause-and-effect link.
Protein quality might explain this difference, said Dr. Linda Van Horn, a professor of preventive medicine at Northwestern University Feinberg School of Medicine and a past chair of the American Heart Association's Nutrition Committee.
Animal proteins are considered "complete" because they contain all the amino acids needed by humans, while most sources of vegetable protein are incomplete, she said. Vegetarians often need to include a wide variety of vegetable protein sources in their diet to get all the amino acids they need.
"One could say that having animal protein simply means you're getting a better quality diet because all the amino acids are present," Van Horn said.
But vegetable proteins also come with lower amounts of saturated fat. Dr. Arturo Tamayo, an assistant professor of neurology at the University of Manitoba in Winnipeg, Canada, said that people will do themselves no favor if they pay attention only to protein intake without considering other dietary risk factors for stroke.
"If we exclusively rely on protein, we are making a mistake," said Tamayo, who wrote an editorial that accompanied the new analysis. "This is a complex disease that needs the control of multiple risk factors and lifestyle changes."
Saturated fat, salt and sugar all have been shown to increase a person's risk of stroke, he said. People who smoke or drink also are at increased risk.