You eat your fruits and vegetables. You hit your five-a-day target most days. You feel like you are doing everything right for your heart. But what if the specific foods you are choosing are leaving you dangerously short of one compound that has been shown to reduce your risk of dying from heart disease by 27%?
That is exactly what a major new study published on June 8, 2026, found. And the results are changing what doctors and nutritionists recommend for heart health.
New Study: Why 5 Fruits and Veggies a Day Isn’t Enough for Your Heart
A landmark study published in the journal Food & Function on June 8, 2026, tracked the diets of more than 30,000 participants across the United Kingdom and the United States using biomarker measurements. The research was conducted by scientists from the University of Reading, Harvard Medical School, the University of California Davis, and Mars, Inc.
The central finding was striking: fewer than one in five people reached the flavanol intake level that has been shown to reduce the risk of heart disease, and that included people who regularly ate five portions of fruit and vegetables every day.
Dr. Javier Ottaviani, the paper’s lead author, explained the significance in plain terms. He said that flavanols can significantly reduce the risk of dying from cardiovascular disease, but only if you consume enough of them. Most people assume that eating plenty of fruit and vegetables covers this, but the specific choices you make matter far more than the total amount.
The study built on findings from the COSMOS trial (COcoa Supplement and Multivitamin Outcomes Study), the largest randomized controlled trial ever conducted on flavanols. COSMOS enrolled 21,442 older adults and found that a daily intake of 500mg of flavanols reduced the risk of death from cardiovascular disease by up to 27%. That is not a marginal benefit, it is a substantial reduction in one of the world’s leading causes of death.
The June 2026 research showed that most people fall well short of the 500mg target even when following standard healthy eating guidance. The researchers found barely any difference in flavanol intake between participants with high versus low fruit and vegetable consumption, which suggests the problem is not about eating more produce but about eating the right kinds.
Professor Gunter Kuhnle of the University of Reading noted that different fruits and vegetables offer very different nutritional benefits beyond vitamins and minerals. As scientific understanding of plant compounds grows, dietary guidelines may need to become far more specific about which foods actually deliver the greatest cardiovascular protection.
This research has direct implications for anyone focused on heart health and challenges the common belief that all fruits and vegetables are equally beneficial for your cardiovascular system.
What Are Flavanols? (And How They Differ from Flavonoids)
If you have heard the term “flavonoids” before, you are in the right neighborhood, but flavanols and flavonoids are not the same thing.
Flavonoids are a large family of over 6,000 naturally occurring plant compounds. They are found in virtually all fruits, vegetables, teas, and grains. The flavonoid family includes several subgroups: flavones, flavanones, isoflavones, anthocyanins — and flavanols.
Flavanols (also called flavan-3-ols) are one specific subgroup within the flavonoid family. They are the particular compounds that the COSMOS trial and the June 2026 study identified as being strongly linked to cardiovascular protection. The most important flavanols include epicatechin, catechin, and proanthocyanidins.
Think of it like this: flavonoids are the entire orchestra, and flavanols are the lead violins doing most of the heavy lifting when it comes to heart health. While other flavonoid subgroups have their own benefits, flavanols are the ones with the strongest clinical evidence for reducing cardiovascular disease risk and cardiovascular death.
Flavanols work through several mechanisms. They help relax blood vessels and improve blood flow by supporting the production of nitric oxide. They reduce inflammation. They act as antioxidants, neutralizing free radicals that damage cells and contribute to chronic disease. And they support the gut microbiome, where beneficial bacteria ferment flavanols into compounds that further support cardiovascular and metabolic health.
This gut connection is especially important. Research has shown that flavanols increase populations of beneficial bifidobacteria and lactobacilli while reducing harmful clostridia. Inflammatory markers in the blood drop. The gut barrier grows stronger. This means flavanols are not just protecting your heart directly, they are strengthening the entire biological system that supports heart health from the inside out.
How Much Do You Need? The 500mg Daily Target
The number to remember is 500mg of flavanols per day.
This is the amount tested in the COSMOS trial that produced a 27% reduction in cardiovascular death risk among 21,442 participants over a median follow-up of 3.6 years. It is also the benchmark that the June 2026 study used to assess whether people were consuming enough flavanols for meaningful heart protection.
To put this in perspective:
The current dietary guidelines in both the United States and the United Kingdom focus on total fruit and vegetable servings without specifying flavanol-rich options. The NHS Eatwell Guide recommends five portions a day of any fruit and vegetables. The USDA Dietary Guidelines for Americans recommend two to three servings daily. Neither set of guidelines mentions flavanols specifically.
The June 2026 study demonstrated that following these generic guidelines does not reliably deliver 500mg of flavanols. You could eat five servings of bananas, iceberg lettuce, cucumber, corn, and carrots every day and get almost no flavanols at all, because those foods simply do not contain them in meaningful amounts.
The key takeaway is not that you need to eat more, it is that you need to choose differently. And the difference between a high-flavanol day and a low-flavanol day can come down to something as simple as choosing plums over bananas, or drinking green tea instead of juice.
If you are already following a plant-based diet rich in berries, apples, and tea, you may already be close to the target. But if your fruit intake is dominated by citrus, melons, and tropical fruits, you are likely falling short.
Top 10 Flavanol-Rich Foods Ranked by Serving
The June 2026 study identified specific foods with the highest flavanol content per typical serving. Here are the top sources, ranked from highest to lowest, based on the data published in Food & Function.
Flavanol Content Per Typical Serving
| Rank | Food | Serving Size | Flavanols (mg) | % of 500mg Target |
| 1 | Plums | 500g punnet (~6 plums) | ~450 mg | 90% |
| 2 | Cranberries | 250g punnet | ~300 mg | 60% |
| 3 | Blackberries | 200g punnet (~1.5 cups) | ~250 mg | 50% |
| 4 | Green tea | 1 cup (brewed) | ~150–200 mg | 30–40% |
| 5 | Broad beans (fava beans) | 150g cooked serving | ~130 mg | 26% |
| 6 | Cherries | 400g punnet (~2 cups) | ~130 mg | 26% |
| 7 | Apples (with skin) | 1 medium apple | ~110 mg | 22% |
| 8 | Strawberries | 200g punnet (~1.5 cups) | ~90 mg | 18% |
| 9 | Blueberries | 150g punnet (~1 cup) | ~80 mg | 16% |
| 10 | Pinto beans | 150g cooked serving | ~50–70 mg | 10–14% |
A few things stand out from this table. Plums are the clear winner, a single punnet gets you to 90% of the daily target in one sitting. Cranberries and blackberries are also exceptionally rich sources. And green tea is one of the most efficient delivery methods per calorie: two and a half cups can get you to 500mg with essentially zero calories.
Apples are a reliable daily staple. One medium apple with the skin provides about 110mg of flavanols, which means that two apples a day cover nearly half the target. This is notable because apples are affordable, available year-round, and easy to eat without preparation. The skin is critical, peeling an apple removes most of the flavanols.
If you have been noticing increased snacking habits as you get older, replacing processed snacks with a handful of blackberries, a bowl of blueberries, or an apple is one of the simplest swaps you can make, and it directly increases your flavanol intake.
The Dark Chocolate Myth: Why It Is Not the Flavanol Source You Think
This section may be disappointing for chocolate lovers, but it is one of the most important things you need to understand about flavanols.
When most people hear about the heart benefits of flavanols, they immediately think of dark chocolate. It has become one of the most persistent health myths of the past decade: “eat dark chocolate for your heart.” Headlines reinforce it constantly. But the reality is far more complicated, and in most cases, dark chocolate is a poor and unreliable source of flavanols.
Here is why.
Processing destroys flavanols. Cocoa beans start out rich in flavanols. But nearly every step of commercial chocolate manufacturing, fermentation, drying, roasting, and especially Dutch processing (alkali treatment), destroys them. Dutch processing, which mellows bitterness and darkens the color, can eliminate up to 90% of the flavanols originally present in the cocoa. The percentage of cocoa on the label tells you almost nothing about how many flavanols survived processing.
The numbers are damning. Testing by ConsumerLab found that flavanol content across popular dark chocolate bars ranged from as little as 2.4mg to 309mg per serving, with no reliable way for consumers to predict which products retain meaningful amounts. To get 500mg of flavanols from most dark chocolate, you would need to consume roughly 700 calories’ worth every single day. That is a third of many people’s daily calorie budget, plus a heavy load of sugar and saturated fat.
The COSMOS trial did not use chocolate. This is critical. The landmark clinical trial that demonstrated the 27% cardiovascular death risk reduction used a standardized cocoa flavanol extract supplement, not chocolate bars, not cocoa powder, not hot chocolate. The researchers needed a precise, controlled dose (500mg flavanols including 80mg epicatechin), and commercial chocolate products simply cannot deliver that consistently.
Harvard’s T.H. Chan School of Public Health has noted that it remains unclear how much daily chocolate consumption would be necessary to obtain a health benefit, because flavanols can be lost when cocoa is processed into commercial bars.
The bottom line: if someone tells you to eat dark chocolate for heart health, ask them which specific product and how many flavanols it contains per serving. In most cases, they will not be able to answer, because the information is not on the label. Your heart is better served by a cup of green tea, two apples, or a bowl of blackberries, all of which deliver reliable, measurable amounts of flavanols without the added sugar, saturated fat, and caloric burden.
Simple Meal Combos to Hit 500mg Daily
Reaching 500mg of flavanols does not require exotic foods, supplements, or radical dietary changes. Here are five practical daily combinations, each designed to hit or exceed the target using commonly available foods.
Combo 1: The Green Tea Day
Two and a half cups of brewed green tea throughout the day (~375–500mg). Add one apple with skin (~110mg) for insurance. This is the lowest-calorie path to 500mg. If you are a tea drinker, you may already be hitting the target without knowing it.
Combo 2: The Berry Breakfast
One cup of blackberries (~250mg) + one cup of blueberries (~80mg) + one medium apple with skin (~110mg) = ~440mg. Add a cup of green tea to comfortably exceed 500mg. Spread these across breakfast and an afternoon snack.
Combo 3: The Summer Fruit Bowl
Three or four plums (~270–360mg) + a handful of strawberries (~90mg) + green tea (~150mg) = 510–600mg. Perfect during summer when stone fruits and berries are in season and at their most affordable.
Combo 4: The Snack Swapper
Replace your usual afternoon snack with a small punnet of cranberries (~300mg) and an apple with skin (~110mg) = ~410mg. A single cup of green tea brings you to 500mg+. This approach works especially well for anyone trying to break free from unhealthy snacking patterns or self-sabotage in weight management.
Combo 5: The Protein-Plus Plate
A serving of broad beans or pinto beans (~70–130mg) with a large side salad including apple slices and berries (~200mg) + green tea with lunch (~150mg) = 420–480mg. Close enough that one more piece of fruit at any point in the day brings you over the line.
The key principle: stack two or three flavanol-rich foods across the day rather than trying to hit the target in a single meal. This mirrors how participants in the COSMOS trial consumed their daily dose, consistently, over time, as part of a regular routine.
If you are already practicing intermittent fasting, plan your flavanol-rich foods within your eating window. Green tea (unsweetened) can be consumed during fasting periods since it is calorie-free and itself delivers a significant flavanol load.
Beyond the Heart: Flavanols, Blood Pressure, Memory, and Diabetes
While the cardiovascular evidence is the strongest, flavanols have demonstrated benefits across several other areas of health.
Blood Pressure
Flavanols support the production of nitric oxide, which relaxes blood vessels and improves blood flow. Multiple clinical trials have shown modest but meaningful reductions in blood pressure with regular flavanol intake, particularly in people with elevated baseline readings. For anyone managing hypertension alongside heart health concerns, increasing flavanol-rich foods is a low-risk, evidence-backed strategy.
Cognitive Function and Memory
The COSMOS-Mind substudy examined whether cocoa flavanols affected cognitive decline in older adults. The results showed measurable improvements in memory among participants who had lower-quality diets at baseline. The researchers described the benefit as “restoration”, bringing cognitive function back to where it should be, rather than enhancement beyond normal levels. For older adults whose diets lack flavanol-rich foods, supplementation or dietary improvement may help preserve mental sharpness.
Insulin Sensitivity and Type 2 Diabetes
Flavanols have been shown to improve markers of insulin resistance. Epicatechin, the most active flavanol compound, appears to enhance insulin signaling and glucose uptake in cells. For anyone managing or at risk for Type 2 diabetes, increasing flavanol intake through diet is a complementary strategy alongside standard diabetes medications.
Anti-Inflammatory and Antioxidant Effects
Chronic low-grade inflammation is a driver of virtually all major diseases, from cardiovascular disease to cancer. Flavanols are potent antioxidants that neutralize free radicals and reduce inflammatory markers in the blood. Their anti-inflammatory properties also have relevance for chronic pain conditions, the same systemic inflammation that damages blood vessels can contribute to persistent pain like lower back pain.
These broader benefits make flavanols one of the most comprehensively studied and well-supported dietary compounds for long-term health. They are not a cure-all, but among the dozens of superfoods that actually have scientific backing, flavanols have more large-scale clinical trial evidence behind them than almost any other.
Frequently Asked Questions
How much flavanols do I need per day?
The COSMOS trial, the largest clinical trial on flavanols involving 21,442 participants, used a dose of 500mg of flavanols per day. At this level, participants saw a 27% reduction in the risk of death from cardiovascular disease. The June 2026 study published in Food & Function confirmed that most people fall well short of this target even when eating five portions of fruit and vegetables daily. Aim for 500mg per day through a combination of flavanol-rich foods like plums, blackberries, apples with skin, and green tea.
What foods are highest in flavanols?
The highest flavanol foods per typical serving are plums (~450mg per 500g), cranberries (~300mg per 250g), blackberries (~250mg per 200g), green tea (~150–200mg per cup), broad beans (~130mg per serving), cherries (~130mg per 400g), apples with skin (~110mg per medium fruit), strawberries (~90mg per 200g), blueberries (~80mg per 150g), and pinto beans (~50–70mg per serving).
Is dark chocolate high in flavanols?
Dark chocolate is not a reliable source of flavanols despite popular belief. Cocoa processing, especially Dutch processing (alkali treatment), can destroy up to 90% of the flavanols originally present in cocoa beans. Testing shows that flavanol content in commercial dark chocolate ranges from as little as 2.4mg to 309mg per serving, with no way for consumers to predict the amount. The COSMOS trial used a standardized cocoa extract supplement, not chocolate. You would need roughly 700 calories of dark chocolate per day to match the 500mg trial dose. Berries, apples, and green tea are far more reliable and lower-calorie sources.
Are 5 fruits and vegetables a day enough for heart health?
Not necessarily. The June 2026 study published in Food & Function found that fewer than one in five people reached the 500mg flavanol target associated with cardiovascular protection, even among those who regularly ate five portions of fruit and vegetables daily. The study found barely any difference in flavanol intake between people with high and low produce consumption. The type of fruit and vegetables matters more than the quantity. Choosing flavanol-rich options like berries, plums, apples, and beans is more important than simply hitting a serving count.
What is the difference between flavanols and flavonoids?
Flavonoids are a large family of over 6,000 plant compounds that include several subgroups: flavones, flavanones, isoflavones, anthocyanins, and flavanols. Flavanols (also called flavan-3-ols) are one specific subgroup within the flavonoid family. They are the particular compounds with the strongest clinical evidence for cardiovascular protection, including epicatechin, catechin, and proanthocyanidins. While all flavonoids have health benefits, flavanols are the ones specifically tested in the COSMOS trial and the June 2026 study.
Which fruits are best for heart health?
Based on the June 2026 study, the best fruits for heart health measured by flavanol content per serving are plums, cranberries, blackberries, cherries, apples with skin, strawberries, and blueberries. These fruits are rich in flavanols, the specific compounds linked to a 27% reduction in cardiovascular death risk. Eating two to three servings of these particular fruits daily, combined with green tea, can help reach the 500mg flavanol target.
Can green tea replace supplements for flavanols?
Green tea is one of the most efficient flavanol sources, providing approximately 150–200mg per brewed cup. Two and a half cups of green tea per day can deliver 375–500mg of flavanols with essentially zero calories. Combined with flavanol-rich fruits like apples or berries, most people can reach the 500mg target through diet alone without supplements. However, if your diet consistently falls short, standardized cocoa flavanol supplements (like those used in the COSMOS trial) are an option to discuss with your healthcare provider.
Do cooking or processing methods affect flavanols in food?
Yes. Flavanols are sensitive to heat, light, and alkaline conditions. Eating fruits raw and with the skin on (especially apples) preserves the most flavanols. For tea, standard brewing preserves flavanols well. For beans, cooking reduces some flavanol content but they remain a meaningful source. The biggest processing losses occur in cocoa, where fermentation, roasting, and Dutch processing can destroy up to 90% of original flavanols.
Sources
- Ottaviani, J. I., Erdman, J. W., Jr., Steinberg, F. M., Manson, J. E., Sesso, H. D., Schroeter, H., & Kuhnle, G. G. C. (2026). Adhering to dietary guidelines does not yield flavanol intake levels associated with beneficial cardiovascular effects. Food & Function, Advance Article. DOI: 10.1039/D6FO00867D
- Sesso, H. D., et al. (2022). Effect of cocoa flavanol supplementation for the prevention of cardiovascular disease events: the COSMOS randomized clinical trial. American Journal of Clinical Nutrition.
- University of Reading Press Release. “Not all five-a-days are equal for heart health.” June 8, 2026.
- Harvard T.H. Chan School of Public Health. “Dark chocolate is best choice for health — but don’t turn it into medicine.”
- COSMOS Trial Registration. ClinicalTrials.gov #NCT02422745. 500 mg/day cocoa flavanols including 80 mg (-)-epicatechin.
Disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider before making significant dietary changes or starting any supplement regimen.
