Mediterranean diet associated with lower risk of stroke in women

Following a Mediterranean diet has been associated with reduced stroke risk in women, a new study has found. (SeventyFour/iStockphoto/Getty Images via CNN Newsource)

As stroke risk rises for women as they age — especially after menopause — a new long-term study suggests that what they eat may play a powerful role in lowering that risk.

Stroke is a leading cause of death among women, and 1 in 5 women in the United States between ages 55 and 75 will have a stroke, according to the U.S. Centers for Disease Control and Prevention.

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However, the award-winning Mediterranean diet may decrease the risk of stroke, according to a new study published Wednesday in Neurology Open Access, a journal of the American Academy of Neurology.

This diet prioritizes eating vegetables, fruits, beans, olive oil, nuts and fish, and limits consuming meat and dairy with moderate consumption of alcohol.

Investigating the effects of the Mediterranean diet

Researchers followed more than 105,000 women who participated in the California Teachers Study, which began in 1995. All participants were public school teachers, administrators or members of the California State Teachers’ Retirement System at the start of the study and ranged in age from 38 to 67.

At the beginning of this long-term study, women completed a detailed food questionnaire about their eating habits and portion sizes over the previous year. Researchers used these responses to calculate overall diet and nutrient intake, then measured how closely each participant followed the Mediterranean diet using a 9-point scoring system.

Points were awarded for eating more vegetables, fruits, legumes, cereals, olive oil, fish, less meat and dairy, and for moderate alcohol intake. Higher scores indicated greater adherence to the Mediterranean diet.

After a follow-up of 20.5 years, researchers found that women who followed the Mediterranean diet had a lower risk of all types of strokes. Specifically, these women were 18% less likely to have any type of stroke, with a 16% lower risk of ischemic stroke — caused by blocked blood flow to the brain — and a 25% lower risk of hemorrhagic stroke, which results from bleeding in the brain.

Findings reinforce existing evidence

Previous studies have shown that the Mediterranean diet may lower the risk for dementia, gum disease, depression, breast cancer and diabetes.

“We’ve known for a long time that this is a healthier type of diet,” said preventive cardiologist Dr. Andrew Freeman, director of cardiovascular prevention and wellness at National Jewish Health in Denver. He was not involved in the study.

Freeman added that many cardiologists often reference the PREDIMED study, which showed an overall reduction in cardiovascular and cerebrovascular events when participants followed a Mediterranean diet, with the most significant benefit seen in stroke prevention. “It’s really no surprise that another study of a different population shows similar reductions in stroke,” he said.

However, the decreased risk for hemorrhagic stroke was particularly surprising, said Dr. Sophia Wang, a senior author of the study. Lifestyle factors are known to influence ischemic stroke risk, but the dietary benefit for hemorrhagic stroke is a new finding, added Wang, a professor in the division of health analytics at the City of Hope, a US cancer and diabetes research and treatment organization.

It is “important to say we continue to get repeat studies showing that a predominantly plant-based diet seems to improve all sorts of outcomes,” Freeman said to CNN, emphasizing the consistency of the evidence.

Wang also pointed to the study’s relevance for women as they age. “Stroke risk for women increases when they reach menopause and is elevated afterward. Our study shows that there are things one can do to minimize that risk, such as adhering to a healthy diet such as the Mediterranean diet.”

Study limitations and big-picture implications

Freeman acknowledged several limitations of the study, including the fact that researchers did not track changes in diet or olive oil consumption over time, noting that these constraints were also identified by the authors.

Still, he said, the findings add to a growing body of evidence.

“This is another study in a long line of well-done research showing that a predominantly low-fat, whole-food, plant-based diet is one of the best ways to prevent a wide range of diseases, particularly cardiovascular and cerebrovascular disease,” Freeman concluded.

By Lily Hautau, CNN