Scientists confirm link between red wine, microbiota and blood pressure
Flavonoids are a class of plant-derived substances whose structure is based on a skeleton consisting of two benzene rings connected by a three-carbon chain. Consumption of foods rich in these polyphenols, such as red wine, green tea, onions, berries, pears, dark chocolate, has a positive effect not only on the digestive system, but also on the level of blood pressure. And such an effect of 15 per cent can be explained by the characteristics of the gut microbiome, said scientists from the Institute for Global Food Security at Queen's University in Belfast, Northern Ireland. The study is published in the journal of the American Heart Association Hypertension.
The fact is that the GI microbiome - the many microorganisms living in the gut - breaks down flavonoids. The microbiota is individual, in addition, experts have previously identified differences in its composition in people with and without cardiovascular disease. Since scientists have long assumed that flavonoids reduce the risk of developing such, often fatal diseases, the authors of the new work decided to study the relationship between a diet rich in these natural compounds, blood pressure and the diversity of the gut microbiome.
The study involved 904 North German adults (25 to 82 years old, 57% male) whose data were stored in the German biobank PopGen. The scientists took into account the consumption of certain foods high in flavonoids over a one-year period, blood pressure readings after a night's rest, at rest, and the composition of the microbiome (assessed by bacterial RNA isolated from stool samples). In addition, volunteers filled out questionnaires on lifestyle, age, body mass index, kilocalorie and fibre intake, bad habits, physical activity, prescribed medications, and history of coronary heart disease.
As the analysis showed, the respondents - lovers of red wine, berries, pears and so on - had a lower level of systolic blood pressure, which depends on the strength of heart contractions and their number per unit time, as well as the resistance of blood vessel walls. In addition, the gut microbiome of these work participants was more diverse than those who did not include flavonoid-containing foods in their diet. Overall, about 120 grams of berries per day correlated with a 4.1 millimetres of mercury column reduction in blood pressure levels, while 350 millilitres of wine per week reduced the figure by 3.7 millimetres of mercury column. This association was partly explained by the diversity of the microbiota.
‘Future studies should examine participants according to metabolic profile to better understand the role of metabolism and the gut microbiome in regulating the effects of flavonoids on blood pressure,’ the scientists said. - ‘Individual variability in flavonoid metabolism may well explain why some people derive more cardiovascular protection benefits from foods rich in these compounds than others.’ But the work had limitations: for example, although the paper's authors made adjustments, unaccounted-for factors such as genetic predispositions and other health conditions may have influenced the results, so the findings may not show direct cause and effect.