08 June 2026
Including blueberries, plums, blackberries, broad beans or cherries (washed down with green tea) in your five-a-day may be the best way to a healthier heart, new research suggests.
A major research study involving scientists from the University of Reading, Harvard Medical School, the University of California Davis, and Mars, Inc., found that fewer than one in five people reached the flavanol intake that has been shown to reduce the risk of heart disease, even including those who regularly ate five portions of fruit and vegetables a day.
The research, published today (Monday, 8 June, 2026) in the journal Food and Function tracked the diets of more than 30,000 participants across the UK and United States using biomarker measurements.
Dr Javier Ottaviani, the paper's lead author, said: "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 what this research shows is that the specific choices you make matter far more than the total amount. Including a handful of blackberries, a whole apple or having a cup of green tea alongside your meal could make a real difference to how much of these beneficial compounds you actually consume and absorb from the diet.”
Previous research, including the largest clinical trial of flavanols, the COSMOS study, found that a daily intake of 500mg of flavanols significantly reduced the risk of dying from heart disease. This new research finds that most people fall well short of that level, even when following standard healthy eating guidance, such as the NHS Eatwell Guide. The foods with the highest flavanol content per portion are:
Plums (500g, roughly one punnet): approximately 450mg of flavanols
Cranberries (250g, roughly one punnet): approximately 300mg of flavanols
Blackberries (200g, roughly one punnet): approximately 250mg of flavanols
Green tea (one 250ml cup): approximately 200mg of flavanols
Broad beans/fava beans (80g, a small handful): approximately 140mg of flavanols
Cherries (400g, roughly one punnet): approximately 130mg of flavanols
Apples with skin (200g, one medium apple): approximately 110mg of flavanols
Strawberries (200g, roughly one punnet): approximately 90mg of flavanols
Blueberries (150g, roughly one punnet): approximately 80mg of flavanols
Pinto beans (40g, two tablespoons dry): approximately 70mg of flavanols
The findings raise wider questions about whether current dietary recommendations around fruit and vegetable consumption could be made more effective.
Professor Gunter Kuhnle of the University of Reading said: "Five-a-day is the right message, but we may need to think more carefully about which five. Different fruits and vegetables offer very different nutritional benefits beyond vitamins and minerals, and as our understanding of these compounds grows, there is a real opportunity to make dietary guidance more specific and more effective. This research is a step towards understanding what that might look like in practice."
Professor Gunter Kuhnle is available for interview. Contact the University of Reading Press Office on 0118 378 5757 or pressoffice@reading.ac.uk.
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. https://doi.org/10.1039/D6FO00867D
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