Flavanol-rich Diet May Lower Blood Pressure

A diet rich in flavan-3-ols, more commonly referred to as flavanols, includes food and beverages such as tea, apples, and berries. According to the European Prospective Investigation into Cancer (EPIC) Norfolk study published in Scientific Reports, this type of diet may lower blood pressure, indicating its ability to support the maintenance of cardiovascular (CVD) health on a population scale.^1,2

Flavanols are a group of bioactive compounds that have demonstrated an ability to help vascular function in prior intervention studies. For this reason, the researchers were interested in investigating flavanols as dietary support in the prevention of CVD diseases due to a lack of reliable data from observational studies on the subject. They noted that such a lack may be in part because of the high variability in the flavanol content of food, making estimates of actual intake difficult without nutritional biomarkers.¹

The researchers assessed the biomarker-estimated flavanol intake of 25,618 citizens of Norfolk in the United Kingdom in relation to their blood pressure and other CVD risk markers, as well as longitudinal associations with CVD risk. However, the researchers strayed from common practice in studies of this kind by not relying on the reported diets of participants, and instead measured flavanol intake through nutritional biomarkers, such as indicators of dietary intake, metabolism, or nutritional status present in the blood.^1,2

"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 lead author Gunter Kuhnle, PhD, a professor of nutrition at the University of Reading, in a press release.²

The results demonstrated that participants with the lowest 10% of flavanol intake and participants with the highest 10% of intake had a difference in blood pressure between 2 and 4 mmHg. Such significant changes in blood pressure are comparable to those with a Mediterranean diet or moderate salt reduction.^1,2

"What this study gives us is an objective finding about the association between flavanols—found in tea and some fruits—and blood pressure. 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,” Kuhnle said.²

Kuhnle explained that the methodology of the study was also of importance in their research.²

“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," Kuhnle said.²

Following this study, researchers from the University of Reading; Cambridge University; University of California, Davis; and Mars, Incorporated assessed the data of the participants from the EPIC Norfolk study and observed that the greatest change in blood pressure due to diet was observed in participants with the highest blood pressure.²

The researchers noted this finding suggests that an increase in flavanol intake among the general public could result in an overall reduction in CVD disease incidence.²

"This study adds key insights to a growing body of evidence supporting the benefits of dietary flavanols in health and nutrition,” said Hagen Schroeter, PhD, chief science officer at Mars Edge, in a press release. “But, perhaps even more exciting was the opportunity to apply objective biomarkers of flavanol intake at a large scale. 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."²

REFERENCES

1. Ottaviani JI, Britten A, Lucarelli D, et al. Biomarker-estimated flavan-3-ol intake is associated with lower blood pressure in cross-sectional analysis in EPIC Norfolk. Scientific Reports. 10,17964(2020). doi: 10.1038/s41598-020-74863-7.
2. High flavanol diet may lead to lower blood pressure. Reading, UK: University of Reading; October 21, 2020. eurekalert.org/pub_releases/2020-10/uor-hfd101620.php. Accessed October 28, 2020.