A new study suggests that not all five-a-days are created equal, which is bad news for anyone who thought their daily apple and banana were doing the heavy lifting. Researchers claim that specific foods - blueberries, plums, blackberries, broad beans, cherries, and green tea - are ideal for boosting flavanols, nutrients that support heart health by reducing inflammation and improving circulation.

The study of 30,000 people in the US and UK found that even regular fruit-and-vegetable eaters often lack these compounds. Fewer than one in five get the recommended 500mg daily intake, according to the journal Food and Function. Lead investigator Dr Javier Ottaviani says simple food switches could “make a real difference,” adding that specific choices matter more than total quantity.

Professor Gunter Kuhnle from the University of Reading agrees that while five-a-day is still sound advice, we may need to think more carefully about which five. “Different fruits and vegetables offer very different nutritional benefits beyond vitamins and minerals,” he said, hinting at a future where dietary guidance gets more specific - and less forgiving of your potato habit.

The research, partially funded by chocolate giant Mars Inc (because who else would fund flavanol studies?), used urine biomarkers to track intake. But heart expert Professor Naveed Sattar from the University of Glasgow cautions that while small trials show flavanols can lower blood pressure, there’s no real evidence yet that they reduce heart attacks or strokes. More trials are needed before we start prescribing blueberries as a substitute for exercise.

Dell Stanford from the British Heart Foundation adds that flavanol content varies wildly depending on where food is grown, climate, ripeness, storage, and even your gut bacteria. So your neighbor’s blueberry might be more virtuous than yours. The BHF and British Nutrition Foundation recommend sticking with a balanced diet full of varied fruits and vegetables - because apparently, even science can’t make eating your greens simple.