A high-protein diet might benefit health in some ways, but depending on what kind of protein a person consumes, it could raise their stroke risk too, suggests a large new study that finds eating lots of red meat ups the likelihood of having a stroke while poultry lowers it.
"The main message from this paper is that the type of protein or the protein package is really important for the risk of stroke. We have to consider protein in the context of the foods," said Dr. Frank Hu, a professor at the Harvard School of and one of the authors of the study.
He and his colleagues collected data from two massive health surveys that tracked tens of thousands of men and women from roughly middle age to their senior and elderly years.
Over 20-some years of the study, nearly 1,400 men and more than 2,600 women had a stroke.
Caused by a blood clot or a burst blood vessel that stops blood flow to the brain, stroke is the third most common cause of death in the United States. Twenty-six out of every 1,000 people in the U.S. have experienced a stroke, according to the Centers for Disease Control and Prevention, and about 800,000 die of stroke each year.
To see what influence different types of dietary protein have on stroke risk, the researchers divided up the people in the study based on how much red meat, poultry, fish, dairy and other sources of protein they typically ate each day.
Men who ate more than two servings of red meat each day -- which was at the high end of the meat eaters -- had a 28 percent increased risk of stroke compared to men who averaged about a third of a serving of red meat each day, the low end of the red meat eaters.
The researchers considered a serving of red meat as four to six ounces of beef or a hamburger patty.
Women who ate nearly two servings of red meat a day had a 19 percent higher risk of stroke than women who ate less than half a serving each day.
A 19 percent increase in stroke risk means that instead of 26 out of every 1,000 people having a stroke, 31 out of every 1,000 people would have one.
The researchers also looked at the change in stroke risk that would come with substituting different forms of protein for one daily serving of red meat: swapping in one serving a day of poultry lowered stroke risk by 27 percent, a serving of nuts or fish was linked to a 17 percent drop in risk and a serving of dairy dropped the risk by 10 to 11 percent.
Dr. Adam Bernstein, the lead author of the study and a researcher at the Cleveland Clinic, said he was not surprised to see that red meat eaters suffer more strokes.
"We've also done work on red meat and diabetes and red meat and coronary heart disease. So it makes sense that these cardio-metabolic diseases are grouped together," Bernstein told Reuters Health.
An earlier study, led by Susanna Larsson at the Karolinska Institute in Stockholm, Sweden, also found that eating red meat had a link to stroke risk (see Reuters Health story of December 31, 2010).