The University of Belfast confirms that putting flavonoid-rich foods on the table helps counter hypertension, thanks to the support of a healthier intestinal flora.
Described as a "silent killer", hypertension, if left untreated, can cause serious health consequences. One way to keep blood pressure under control is through diet. And it is in this area that a recent discovery has been made, concerning flavonoids, the antioxidant substances belonging to the polyphenol family found, for example, in berries, black grapes, apples, pears, dark chocolate, tea and red wine.
According to research conducted by Queen's University Belfast, a diet richer in flavonoids is associated with a clinically significant reduction in blood pressure levels. But that is not all. The Irish researchers found that the health of the intestinal flora also benefits. The health and richness of the microbiota is, in fact, important for the gut to metabolise flavonoids more effectively, supporting them in their protective "work" on the cardiovascular system.
It is not the first time that science has highlighted the relationship between a flavonoid-rich diet and cardiovascular health, but the Irish study is the first to reveal the key role of the microbiota — the population of microorganisms (bacteria, fungi, protozoa and viruses) that colonises our gut — in lowering blood pressure.
Recent studies had already uncovered a connection between gut bacteria and heart attack, and also that the microbiota of individuals with heart or circulatory problems differs from that of those who do not suffer from such conditions. A difference that the Irish researchers also found. The subjects analysed responded differently to the flavonoid-rich diet because each of them processed flavonoids, through their own gut bacteria, in a different way.
The study, conducted on more than 900 individuals aged between 25 and 82 and published in Hypertension, highlighted that eating a cup of berries every day reduces systolic (upper) blood pressure by 4.1 mm Hg (millimetres of mercury). A reduction attributable 12 per cent to the richness of the intestinal flora; drinking around 2.8 glasses of red wine per week lowers the upper blood pressure reading by 3.7 mm Hg, an improvement owing 15 per cent to the health of the microbiota.
"Our gut microbiome (the totality of the genetic heritage expressed by the microbiota, ed.) plays a key role in metabolising flavonoids to enhance their cardioprotective effects," said Aedín Cassidy, the study's lead researcher, who added: "the study has provided evidence that these blood pressure-lowering effects can be achieved through simple modifications to the daily diet. The findings indicate that future studies should examine participants according to their metabolic profile in order to more accurately investigate the roles of metabolism and intestinal flora in regulating the effects of flavonoids on blood pressure."