Greater microbial diversity in the gut microbiome is connected to higher consumption of flavonoid-rich foods, and the metabolism thereof may be at the basis of flavonoids’ connection to lower blood pressure, according to a new study in Hypertension (DOI: 10.1161/HYPERTENSIONAHA.121.17441).
Researchers from Queen’s University Belfast, Northern Ireland, assessed how the composition of the gut microbiome could explain the association between regular high consumption of flavonoids and blood pressure. The study included more than 900 adults from Norther Germany; gut microbiome composition was sequenced from 16S ribosomal RNA genes, while food journals were used to assess types of flavonoid-rich food consumption.
Study participants with the highest intake of flavonoid-rich foods—notably berries, red wine, apples and pears—had lower systolic blood pressure levels (-2.9%), as well as greater microbial diversity and lower abundance of Parabacteroides, compared to participants with the lowest consumption levels. For context, the researchers noted drinking 250ml/week of red wine was associated with an average of 3.7mm Hg lower systolic blood pressure; similarly consuming 80 g/day of berries was associated with an average reduction of systolic blood pressure levels of 4.1mm Hg.
Ultimately, up to 15% of the association between consumption of flavonoid-rich foods and systolic blood pressure was explained by the gut microbiome. The researchers concluded further research should focus on inter-individual variability in the gut microbiome in mediating the cardiovascular effects of flavonoid-rich foods.
Prof. Aedin Cassidy, chair of nutrition and preventive medicine at the Institute for Global Food Security (IGFS) at QUB, commented in a statement: “Our findings indicate future trials should look at participants according to metabolic profile in order to more accurately study the roles of metabolism and the gut microbiome in regulating the effects of flavonoids on blood pressure. A better understanding of the highly individual variability of flavonoid metabolism could very well explain why some people have greater cardiovascular protection benefits from flavonoid-rich foods than others.”
Whether the benefits could be delivered via food supplements compared to dietary intake is unknown, according to Prof. Cassidy, as the study focused on food intake.