A comprehensive long-term study spanning over two decades has revealed compelling evidence that adhering to a Mediterranean diet can significantly reduce the risk of stroke, with reductions reaching up to 25% for certain types. The research, published in the journal Neurology Open Access, provides new insights into how dietary choices can impact cardiovascular health, particularly in preventing this leading cause of death and disability worldwide.
Key Findings from the 21-Year Research
The study, conducted by researchers from the United States and Greece, involved 105,614 women in California with an average age of 53 at the outset, all of whom had no prior history of stroke. Participants were followed for an average of 21 years, making this one of the most extensive investigations into the diet's effects on stroke risk to date.
How the Study Measured Diet Adherence
Participants were assigned a score from zero to nine based on how closely they followed the Mediterranean diet. Points were awarded for consuming above-average amounts of specific food categories, including:
- Wholegrain cereals
- Fruits and vegetables
- Legumes
- Olive oil
- Fish
- Moderate alcohol consumption
Additionally, points were given for consuming below-average amounts of red meat and dairy products. In the study, 30% of participants fell into the highest adherence group (scores 6-9), while 13% were in the lowest group (scores 0-2).
Significant Reductions in Stroke Risk
After adjusting for factors such as smoking, physical activity, and high blood pressure, the results were striking. Those in the highest adherence group experienced an 18% lower risk of stroke overall compared to those in the lowest group. More specifically, the risk reduction was 16% for ischemic stroke and 25% for hemorrhagic stroke.
Understanding the Types of Stroke
Ischemic stroke, caused by blocked blood flow to the brain, is the most common type, accounting for the majority of cases. Hemorrhagic stroke, resulting from bleeding in the brain, is less frequent but often more severe. The study's findings are particularly notable for hemorrhagic stroke, as few large-scale studies have previously examined this subtype in relation to diet.
Expert Reactions and Implications
Dr. Sophia Wang, the study author from the City of Hope Comprehensive Cancer Centre in California, emphasised the importance of these results. "Our findings support the mounting evidence that a healthy diet is critical to stroke prevention," she stated. "We were especially interested to see that this finding applies to hemorrhagic stroke, as few large studies have looked at this type of stroke."
Independent experts have welcomed the study, highlighting its potential public health impact. Juliet Bouverie, Chief Executive of the Stroke Association, noted that "nine out of 10 strokes were preventable," underscoring the "huge potential" for reducing stroke incidence through dietary changes. She added, "It's long been known that eating a Mediterranean diet can help to lower the risk of cardiovascular diseases, such as stroke. We welcome how this has now been shown to reduce the risk of total, ischemic, and haemorrhagic strokes."
Study Limitations and Future Research
While the study offers robust evidence, it has some limitations. It focused exclusively on women, and participants self-reported their dietary data, which could introduce bias. However, the large sample size and lengthy follow-up period lend credibility to the findings.
Dr. Wang called for further studies to confirm these results and explore the underlying mechanisms. "Further studies are needed to confirm these findings and to help us understand the mechanisms behind them so we could identify new ways to prevent stroke," she explained.
Global Context and Health Benefits
Stroke remains a major global health challenge, with over 15 million people experiencing a stroke annually. Of these, 5 million die, and another 5 million are left permanently disabled. The Mediterranean diet, rich in olive oil, nuts, seafood, whole grains, and vegetables, has been linked to various health benefits, including reduced risks of heart disease and certain cancers. This study adds to the growing body of evidence supporting its role in stroke prevention.
In summary, this long-term research underscores the powerful impact of dietary choices on health outcomes. By adopting a Mediterranean-style diet, individuals may significantly lower their risk of stroke, contributing to better overall cardiovascular health and quality of life.
