King's College London has just released a ground-breaking study that followed over 3,100 people for more than 11 years. What makes it special? Instead of just asking people what they ate, researchers also measured evidence of plant compounds in their urine - giving us the clearest picture yet of how these powerful nutrients protect our hearts.
What Did They Find?
The research tracked participants from the TwinsUK study, which has been following British twins for over 30 years. The results were clear: people who regularly ate a variety of plant-based whole foods rich in polyphenols (natural plant compounds with health benefits) had lower risk scores for heart disease.
This might not sound surprising, but what's interesting is how they measured it. Rather than just counting nutrients, researchers looked at how often people ate from a list of 20 polyphenol-rich foods. They also tested urine samples from 200 participants to confirm that these plant compounds were being absorbed by the body.
Which Foods Matter Most?
Participants were scored on how much they ate from 20 different food groups, including tea, coffee, wholegrains, berries, dark chocolate, apples, pears, grapes, citrus fruits, potatoes, carrots, onions, peppers, garlic, green vegetables, beans and pulses, soybeans, nuts, and olive oil.
The more variety and frequency of these foods in someone's diet, the better their heart health markers looked.
The Most Powerful Plant Compounds
When researchers analysed the urinary samples to see which plant compounds were being absorbed and utilised by the body, certain foods emerged as particularly beneficial for cardiovascular health:
Berries were particularly impressive, contributing anthocyanins - the natural pigments that give them their deep purple and red colours. These showed strong links to heart health benefits.
Coffee, tea, and red wine delivered beneficial compounds called phenolic acids.
Olive oil provided tyrosols, another protective compound.
People with higher levels of these plant compounds in their urine had lower blood pressure, better cholesterol levels, and reduced cardiovascular risk scores.
What Does This Mean for You?
The good news is that protecting your heart doesn't require complicated meal plans or expensive supplements. It's about regularly including a variety of colourful, plant-based whole foods in your everyday eating.
If you're already drinking tea or coffee, eating berries or berry powder and other fruits, using olive oil, choosing wholegrains, and including plenty of vegetables, you're on the right track. This is essentially what makes the Mediterranean diet so beneficial.
Five Simple Ways to Add More Plant Power to Your Diet
Want to boost your intake without overhauling your entire diet? Here are five easy changes:
- Add berry powder to your morning routine - Freeze-dried berry powders like haskap (incredibly rich in those beneficial anthocyanins) can be stirred into yoghurt, porridge, or smoothies. No washing, no waste, no berries going mouldy in the fridge.
- Finish with olive oil - Drizzle extra virgin olive oil over your cooked dishes rather than cooking with it. This preserves the heat-sensitive beneficial compounds.
- Use herbs generously - Fresh parsley, oregano, and thyme aren't just for flavour - add them by the handful for a serious nutritional boost.
- Mix up your hot drinks - If you only drink coffee, try alternating with green or black tea to get a wider variety of beneficial compounds.
- Make nuts a daily habit - A small handful (about 30g) of mixed nuts every day provides their own beneficial plant compounds, plus the healthy fats in nuts help your body absorb fat-soluble nutrients from other foods in your meal.
The Bottom Line
This study gives further evidence that eating a varied diet rich in colourful plant foods genuinely makes a measurable difference to heart health. The best part? These aren't exotic superfoods - they're everyday foods that can easily become part of your normal routine.
Research
Li, Yong, et al. “Higher Adherence to (Poly)Phenol-Rich Diet Is Associated with Lower CVD Risk in the TwinsUK Cohort.” BMC Medicine, vol. 23, no. 1, 2025, p. 645, pubmed.ncbi.nlm.nih.gov/41299455/, https://doi.org/10.1186/s12916-025-04481-5.