Food and beverages that are high in flavanols such as apples, berries, and tea can help lower blood pressure, according to a study from the University of Reading. The research is the first of its kind to objectively measure the effect of a specific compound on blood pressure among thousands of people.
“Previous studies of large populations have always relied on self-reported data to draw conclusions, but this is the first epidemiological study of this scale to objectively investigate the association between a specific bioactive compound and health,” said study lead author Professor Gunter Kuhnle. “We are delighted to see that in our study, there was also a meaningful and significant association between flavanol consumption and lower blood pressure.”
The researchers compared the diets and blood pressure readings of more than 25,000 adults in the UK. Instead of relying on self-reported flavanol intake, the team analyzed nutritional biomarkers present in the blood.
“This study adds key insights to a growing body of evidence supporting the benefits of dietary flavanols in health and nutrition. But, perhaps even more exciting was the opportunity to apply objective biomarkers of flavanol intake at a large scale,” said Hagen Schroeter. “This enabled the team to avoid the significant limitations that come with past approaches which rely on estimating intake based on self-reported food consumption data and the shortcomings of current food composition databases.”
The study revealed that participants with the highest levels of flavanol intake had a difference in blood pressure of between 2 and 4 mmHg compared to individuals who had the least flavanols in their diet. This drop in blood pressure is comparable to that observed among people following a Mediterranean diet or Dietary Approaches to Stop Hypertension (DASH) diet. The positive effect of flavanols was found to be even more pronounced in participants with hypertension.
“What this study gives us is an objective finding about the association between flavanols – found in tea and some fruits – and blood pressure,” said Professor Kuhnle. “This research confirms the results from previous dietary intervention studies and shows that the same results can be achieved with a habitual diet rich in flavanols. In the British diet, the main sources are tea, cocoa, apples and berries.”
“The methodology of the study is of equal importance. This is one of the largest ever studies to use nutritional biomarkers to investigate bioactive compounds. Using nutritional biomarkers to estimate intake of bioactive food compounds has long been seen as the gold standard for research, as it allows intake to be measured objectively.”
“The development, validation and application of the biomarker was only possible because of the long-term commitment of all collaborators. In contrast to self-reported dietary data, nutritional biomarkers can address the huge variability in food composition. We can therefore confidently attribute the associations we observed to flavanol intake.”
The findings suggest that if the general public increased its flavanol intake, there could be a significant reduction in the prevalence of cardiovascular disease, which is the leading cause of death worldwide.
The study is published in the journal Scientific Reports.