Recent studies have found that foods that have high amounts of flavanol can help to lower blood pressure. The study was conducted on 25,000 participants in the UK, and it measured the biomarkers of the participants’ urine instead of relying on their answers. Participants could have kept food diaries, but those are often flawed because people will often understate how much sugar or protein they have eaten. Biometric measurements provide a more accurate idea of what the participants consumed. It was more difficult to determine how much flavanol was consumed since foods can greatly vary in how much of the compound they contain.
The urine also provides a fairly accurate idea of how much flavonoid was consumed than in what was eaten to increase the levels. The participants who consumed more flavonoids had lower systolic blood pressure, though the effect was relatively small. Researchers indicated that the differences was roughly the same as the participants having adopted either the Mediterranean or DASH diet, or reducing salt. There was no link between flavanol and cardiovascular disease or mortality. To determine these will require larger, more long-term studies.
In the UK, tea is the most commonly consumed flavanol source. Flavanol are also found in cocoa (but not chocolate), nuts, apples, and berries. The compound is common in plants as a way to protect them from being eaten. It is perhaps ironic that the protective compound has health benefits when consumed by people.
For more details about the studies, you can read the full article, Flavanols – Found in Tea, Berries and Apples – May Reduce Blood Pressure, Study Finds.