The analysis of data from the ongoing, prospective California Teachers Study, which was designed to examine dietary patterns and breast cancer risk, found that following a Mediterranean diet reduced ischemic stroke risk by up to 18%, stroke neurologist Ayesha Sherzai, MD, of Columbia University Medical Center, New York City, said.
Mediterranean Diet Followers Had Lower Risk
The more closely the women followed the diet, the lower their risk of ischemic stroke, even after researchers adjusted for potential confounders like physical activity, smoking status, and cardiovascular risk factors.
“With stroke being one of the biggest disease burdens in the U.S. and throughout the world, and treatments not being as extensive as we would like them to be, diet is a risk factor that people can control,” Sherzai said.
The California Teachers Study enrolled close to 133,500 female teachers from across the state who were recruited in 1994. At recruitment the women filled out baseline lifestyle questionnaires, which included detailed information about their eating habits.
In the newly reported analysis, Sherzai and colleagues evaluated these eating patterns using a validated 9-point Mediterranean diet scoring system.
“The question was ‘In a U.S. population of women, what is the association between adhering to the Mediterranean diet and stroke risk, specifically stroke subtypes?” she said. “That hasn’t really been studied.”
In revised stroke prevention guidelines made public last fall, the American Heart Association (AHA)/American Stroke Association (ASA) for the first time recommended following a Mediterranean-style diet as a strategy to lower stroke risk. The recommendation followed the publication of several studies showing the diet to lower cardiovascular and stroke risk, including a 2013 randomized trial, published in the New England Journal of Medicine, which found that following a Mediterranean diet reduced the risk of heart attack and stroke in people at high risk for the events.
AHA also identified eating a healthy diet as one of the most important strategies for lowering cardiovascular risk in its initiative to reduce cardiovascular diseases and strokes by 20% by 2020.
Less Than 1% of Adults Over 50 Have Ideal Diets
But Sherzai said fewer than 1% of U.S. adults age 50 and over have an ideal dietary score. That is far lower than any other lifestyle factor related to stroke risk, she said.
In the newly reported analysis, women who ate diets high in fruits, vegetables, legumes, and monounsaturated fatty acids (MUFAs), scored high on the scale and points were deducted when the diets were high in meats, dairy, and sugar.
Olive oil, olives, avocados, and many nuts and seeds are good sources of MUFA.
“The higher the scores, the lower the stroke risk,” Sherzai said. “This basically confirms what other studies have found, but we were able to delineate between ischemic and hemorrhagic stroke.”
She added that it was not a big surprise that following a Mediterranean diet did not lower hemorrhagic stroke risk because diet does not really affect risk factors associated with stroke caused by weakened vessels that rupture and bleed into the brain.
And she said eating a healthier diet that may lower stroke risk shouldn’t mean big changes for most people.
“We aren’t saying that everybody has to strictly follow a Mediterranean diet, because we now know the components of this diet that are important,” she said. “Eating a mostly plant-based diet and eating less meat and saturated fats can make a real difference in stroke risk,” she said, adding that most people should be able to make small, but significant changes in their diet, like switching from butter to olive oil and cutting back on their consumption of sugar, meats, and whole-fat dairy products.
Findings from the study were reported Thursday at the annual meeting of the International Stroke Conference, sponsored by the American Heart Association/American Stroke Association.
The researchers disclosed no relevant relationships with industry.