Researchers looked at 133 studies to find out which foods and eating patterns help your heart’s blood vessels stay healthy. They found that eating fruits, vegetables, tea, nuts, and following a Mediterranean diet (lots of vegetables, fish, and olive oil) all helped improve how well blood vessels work. Tea showed the biggest benefit. The study suggests these foods may help prevent heart disease, though scientists say we need more research to be completely sure about how much these foods help.

The Quick Take

  • What they studied: Which foods and eating patterns help keep your heart’s blood vessels healthy and working properly
  • Who participated: 102 different research studies involving adults who tried eating different foods or following different diets for at least 4 weeks
  • Key finding: Tea, Mediterranean diet, cocoa, nuts, seeds, soy, vegetables, and fruits all improved how well blood vessels work. Tea had the biggest effect, improving blood vessel function by about 3.22%
  • What it means for you: Adding these foods to your diet may help protect your heart, but this isn’t a cure-all. You should still talk to your doctor about heart health, and remember that losing weight alone didn’t help blood vessels in these studies

The Research Details

Scientists looked at 133 high-quality studies where people were randomly assigned to eat certain foods or follow certain diets. They focused on studies that lasted at least 4 weeks and measured something called ‘flow mediated dilation’ (FMD), which is a fancy way of saying how well your blood vessels can stretch and relax. This is important because healthy blood vessels that can stretch easily are a sign of a healthy heart.

The researchers separated the studies into two groups: 102 studies about specific whole foods (like apples, broccoli, or almonds) and 31 studies about overall eating patterns (like the Mediterranean diet). They combined all the results to see which foods and diets worked best.

They also checked each study for problems that might make the results unreliable, and they looked for signs that studies with better results might have been more likely to get published (which could make the overall picture look better than it really is).

This type of study is important because it combines information from many different research projects. Instead of relying on just one study, which might have been done differently or had different types of people, combining results from 133 studies gives us a much clearer picture of what actually works. The researchers also measured something that happens early in heart disease (before you have a heart attack), so these findings might help prevent serious problems before they start.

The researchers were honest about the fact that not all studies were perfect. They rated the certainty of their findings as ‘moderate to low,’ which means we should be somewhat confident but not completely certain. Some studies had problems with how they were done, and some were smaller than ideal. The biggest and most reliable finding was about tea, which showed the most consistent improvement across studies.

What the Results Show

The foods and diets that consistently helped blood vessels work better were: tea (the biggest improvement at 3.22%), Mediterranean diet (2.32% improvement), cocoa (1.68%), nuts and seeds (1.39%), soy (1.58%), vegetables (1.37%), and fruits (0.85%). These percentages might sound small, but they represent real improvements in how your blood vessels function.

Tea was the clear winner, showing the biggest benefit across all the studies. This might be because tea contains special compounds called antioxidants that help protect your blood vessels. The Mediterranean diet, which focuses on vegetables, fish, olive oil, and whole grains, also showed strong and consistent benefits.

Interestingly, weight loss by itself didn’t improve blood vessel function when people lost less than 10% of their body weight. This suggests that what you eat might be just as important as how much you weigh when it comes to heart health.

All of these improvements were measured in a very specific way (blood vessel stretching ability), which is considered an early warning sign of heart disease. If your blood vessels can stretch and relax easily, that’s a good sign for your heart’s health.

The researchers also looked at different types of fruits and vegetables separately and found that they all helped, though the exact amount varied. They noticed that the benefits seemed to work best when people stuck with these foods for at least a month. Some studies tested different amounts of these foods, and generally, more of these healthy foods meant better results, but there wasn’t a clear ‘magic amount’ that worked for everyone.

These findings fit well with what doctors have been recommending for years about eating more fruits, vegetables, and following a Mediterranean diet for heart health. However, this is one of the largest and most thorough reviews of this specific type of evidence (looking at blood vessel function) ever done. Previous research suggested these foods were good for your heart, but this study provides stronger evidence by combining results from so many studies.

The researchers were careful to point out several important limitations. First, most of the studies were relatively short (just a few weeks to a few months), so we don’t know if these benefits last for years. Second, many studies were small, which means the results might not apply to everyone. Third, the quality of evidence was rated as moderate to low, meaning some studies had problems with how they were designed. Fourth, most studies involved people who were already fairly healthy, so we don’t know if these foods help people who already have heart disease. Finally, the studies measured blood vessel function in a lab setting, which might not perfectly reflect what happens in real life.

The Bottom Line

Based on this research, here are evidence-based recommendations: (1) Drink tea regularly—this showed the strongest benefit and is easy to add to your routine (Confidence: Moderate). (2) Follow a Mediterranean-style diet with lots of vegetables, fish, olive oil, and whole grains (Confidence: Moderate). (3) Eat more fruits and vegetables daily (Confidence: Moderate). (4) Include nuts, seeds, and soy products in your diet (Confidence: Moderate to Low). (5) Enjoy cocoa or dark chocolate in moderation (Confidence: Low). These recommendations work best as part of an overall healthy lifestyle, not as replacements for exercise or other healthy habits.

These findings are most relevant for adults who want to prevent heart disease or improve their heart health. They’re especially important for people with risk factors like high blood pressure, high cholesterol, or a family history of heart disease. However, if you already have heart disease, you should talk to your doctor before making major diet changes. These findings are less clear for children, pregnant women, or people with certain medical conditions. If you’re taking blood pressure medications or have other health conditions, check with your doctor before making big diet changes.

Based on the studies reviewed, you might see improvements in blood vessel function within 4-8 weeks of consistently eating these foods. However, the real benefits for preventing heart disease happen over months and years. Don’t expect to feel dramatically different right away—these changes work quietly to protect your heart. The longer you stick with these eating patterns, the better the benefits seem to be.

Want to Apply This Research?

  • Track daily servings of heart-healthy foods: record cups of tea consumed, servings of fruits and vegetables, ounces of nuts/seeds, and whether you followed Mediterranean diet principles. Aim for at least 2-3 servings of vegetables, 1-2 of fruit, 1 cup of tea, and a small handful of nuts daily.
  • Start with one small change: replace one sugary drink per day with tea, or add one extra vegetable to dinner. Once that becomes a habit (2-3 weeks), add another change. This gradual approach is more sustainable than trying to change everything at once.
  • Use the app to track consistency over 8-12 weeks, then check in with your doctor for blood pressure or cholesterol measurements to see if your heart health markers are improving. Create weekly goals for each food group and celebrate when you hit them. Share progress with a friend or family member for accountability.

This research summary is for educational purposes only and should not replace professional medical advice. The findings suggest these foods may help heart health, but individual results vary. If you have heart disease, high blood pressure, take medications, or have other health conditions, consult your doctor before making significant diet changes. This study measured blood vessel function in a lab setting, which may not perfectly reflect real-world health outcomes. Always talk to your healthcare provider before starting new dietary patterns, especially if you have existing health conditions or take medications.