Researchers followed over 7,400 people at high risk for heart disease for about 4 years to see how different healthy eating patterns affected their chances of having a stroke. They found that people who closely followed a Mediterranean diet—which emphasizes olive oil, fish, vegetables, and whole grains—had about 75% fewer strokes than those who didn’t follow it. A similar diet that combines Mediterranean and DASH principles showed similar benefits. However, two other healthy diets tested didn’t show the same protective effect. This suggests that not all healthy diets work equally well for preventing strokes, and the Mediterranean approach may be particularly powerful for people at high risk.

The Quick Take

  • What they studied: Whether following four different types of healthy eating plans could reduce the risk of having a stroke in people who already had a high chance of heart disease
  • Who participated: 7,447 adults at high risk for heart disease who were part of a large Spanish study. Researchers tracked their eating habits and health outcomes for about 4 years
  • Key finding: People who most closely followed a Mediterranean diet had about 75% fewer strokes compared to those who followed it least. A Mediterranean-DASH combination diet showed similar protection. The other two diets tested didn’t show significant benefits
  • What it means for you: If you’re at risk for heart disease or stroke, switching to a Mediterranean-style diet may significantly lower your chances of having a stroke. However, this research is strongest for people with existing heart disease risk factors, and you should talk with your doctor about what diet is right for you

The Research Details

This study used data from a large, well-designed experiment called PREDIMED that was conducted in Spain. Researchers didn’t randomly assign people to different diets; instead, they looked back at what people actually ate using detailed food questionnaires and tracked whether they had strokes. They calculated four different ‘diet scores’ to measure how well each person followed Mediterranean, DASH, Mediterranean-DASH, and Planetary Health diets. They then compared stroke rates between people who scored highest and lowest on each diet.

The researchers were careful to account for other factors that affect stroke risk, like age, smoking, exercise, and medications. They followed participants for an average of 4.3 years and recorded 135 stroke cases during this time.

This approach is valuable because it shows real-world results in people who actually chose their own diets, rather than forcing people into artificial eating patterns. The PREDIMED trial is one of the most respected nutrition studies ever conducted. By looking at multiple diet types in the same group of people, researchers could fairly compare which diets work best

This study has several strengths: it involved a large number of participants, had a long follow-up period, used detailed dietary assessments, and carefully controlled for other health factors. The main limitation is that it’s observational—people chose their own diets, so we can’t be 100% certain the diet caused the benefit rather than other lifestyle differences. The study was conducted in Spain, so results may differ in other populations with different food availability and cultures

What the Results Show

Among the 7,447 participants, 135 people had strokes during the study period (112 ischemic strokes, which are caused by blood clots, and 23 hemorrhagic strokes, which are caused by bleeding). People who followed the Mediterranean diet most closely had a 74% lower risk of total stroke compared to those who followed it least. Specifically, the risk was reduced from what would be expected to about one-quarter of that risk. A similar diet combining Mediterranean and DASH principles showed nearly identical protection, with a 75% risk reduction.

For ischemic strokes specifically (the most common type), the Mediterranean diet showed a 73% risk reduction, and the Mediterranean-DASH combination showed a 74% reduction. These are very substantial protective effects. In contrast, the traditional DASH diet alone and the Planetary Health Diet Index did not show statistically significant protection, though the Planetary Health Diet showed a trend toward benefit that didn’t quite reach statistical significance.

The study found that the benefits were consistent across different groups of participants, suggesting the Mediterranean diet works well for various types of high-risk individuals. The researchers also noted that the protective effect appeared to be related to how closely people actually followed the diet—the more closely they adhered, the greater the benefit. This dose-response relationship strengthens confidence that the diet itself, rather than other factors, was responsible for the protection

These findings align with previous research showing that Mediterranean diets protect against heart disease and early death. However, this is one of the first large studies to specifically examine stroke prevention with multiple diet types in the same population. Previous studies on DASH diet and stroke prevention have shown mixed results, which this study helps clarify by showing DASH alone may be less protective than Mediterranean approaches. The strong results for Mediterranean diet are consistent with decades of research in Mediterranean countries showing lower stroke rates

The study was conducted primarily in Spain with Mediterranean populations, so results may not apply equally to other ethnic groups or regions with different food cultures. Because people chose their own diets rather than being randomly assigned, we cannot prove the diet caused the benefit—other healthy lifestyle factors often go hand-in-hand with Mediterranean eating. The study only followed people for about 4 years, so we don’t know about long-term effects. Additionally, the number of stroke cases (135 total) was relatively small, which means some findings could be due to chance

The Bottom Line

If you are at high risk for heart disease or stroke, adopting a Mediterranean diet appears to offer strong protection (high confidence). This diet emphasizes olive oil, fish, vegetables, legumes, whole grains, nuts, and moderate wine consumption while limiting red meat and processed foods. A Mediterranean-DASH combination approach also appears effective. Standard DASH diet alone showed less clear benefit in this study. These recommendations are strongest for adults with existing heart disease risk factors and should be discussed with your healthcare provider

This research is most relevant for people with high cardiovascular disease risk, including those with high blood pressure, high cholesterol, diabetes, obesity, or a family history of heart disease. It’s also valuable for anyone interested in stroke prevention. The findings are less directly applicable to young, healthy people without risk factors, though Mediterranean diet is generally considered healthy for everyone. People with specific medical conditions or dietary restrictions should consult their doctor before making major dietary changes

Stroke prevention is a long-term benefit. In this study, the protective effects were observed over 4+ years of consistent diet adherence. You might notice other benefits of Mediterranean eating—like improved energy, better digestion, or weight loss—within weeks to months. However, the stroke-protective effects likely develop gradually over months and years of consistent adherence

Want to Apply This Research?

  • Track daily servings of Mediterranean diet components: olive oil use (tablespoons), fish/seafood meals (weekly count), vegetables (servings), legumes (servings), whole grains (servings), and nuts (servings). Create a weekly Mediterranean diet adherence score (0-100%) based on how many components you included each day
  • Start by making one Mediterranean swap per week: replace butter with olive oil, add fish to one meal, increase vegetable portions, or try a new legume-based recipe. Use the app to log these changes and build momentum toward full Mediterranean diet adoption
  • Monthly review of diet adherence patterns and correlation with energy levels, weight, and cardiovascular markers (if tracked). Set a goal to maintain 70%+ Mediterranean diet adherence weekly. Use app notifications to remind users about key components (fish twice weekly, daily vegetables, olive oil usage) and celebrate consistency milestones

This research suggests Mediterranean diet may reduce stroke risk in people at high cardiovascular disease risk, but it is not a substitute for medical advice. Stroke risk depends on many factors including genetics, blood pressure, cholesterol, diabetes, smoking, and exercise. Before making significant dietary changes, especially if you have existing health conditions or take medications, consult with your doctor or registered dietitian. This study was observational, meaning we cannot prove diet alone caused the benefits. Individual results may vary based on genetics, overall lifestyle, and other health factors.