Study: Flavonoid-Rich Foods Could Improve Gut Health and Reduce Blood Pressure

Flavonoids, typically found in vegetables, fruits, chocolate, and red wine, may lower blood pressure, according to a recent study. Researchers found that the benefits of a flavonoid-rich diet are associated with a greater diversity of gut bacteria.

Based on data from more than 900 adults in Germany, the study concluded that up to 15.2% of the association between flavonoids and systolic blood pressure could be explained by gut microbiota. 

“What we eat plays a critical role in shaping our gut microbiome but little is known about the relative importance of plant foods and specific constituents called flavonoids. This is one of the first studies to address this,” Aedín Cassidy, PhD, director for interdisciplinary research at the Institute for Global Food Security at Queen's University Belfast and co-author of the study, tells Verywell.

What Are Flavonoids?

Flavonoids are antioxidants and anti-inflammatory compounds found in certain plant foods like red wine, tea, berries, apples, and dark chocolate. 

“Unlike many other food constituents, the flavonoids are predominantly metabolized in the gut,” Cassidy says.

Scientists are still learning about the biological mechanisms of flavonoids and how exactly gut microbiome affects health outcomes. But a previous study found that flavonoids may reduce risks of Alzhemier’s Disease, cardiovascular diseases, and diabetes, among others.

Cassidy adds that the type and amount of gut bacteria can vary from individual to individual, though recent research has suggested that the presence of unhealthy gut bacteria is associated with a higher risk of heart attack and stroke.

Flavonoids, Gut Bacteria, Blood Pressure

The new study found that even consuming small amounts of flavonoid-rich foods can significantly lower blood pressure.

For instance, eating 1.5 servings of berries per day was associated with a 4.1 mmHg reduction in systolic blood pressure, Cassidy says. Drinking 2.8 glasses (125ml) of wine every week was associated with an average of 3.7 mm Hg lower systolic blood pressure level as well.

Dietary flavonoids have probiotic-like properties that can stimulate the growth of certain gut bacteria. Incorporating flavonoids into one’s daily diet can be as simple as topping yogurt with blackberries, drinking green tea instead of coffee in the afternoon, and grabbing an apple or a pear for a snack. 

Promoting gut health has been an extremely popular wellness trend in the last few years. Scientists have pointed to fermented foods like yogurt and kombucha as options to increase gut bacteria diversity and reduce inflammation. Some have even suggested “rewilding” the microbiome by reverting modern diets to a pre-industrialized state.

However, others have also emphasized that the term “gut health” is poorly understood. 

Heidi M. Staudacher and Amy Loughman, researchers at the Food & Mood Centre at the Deakin University in Australia, wrote in The Lancet that listicles with top 10 gut health foods are not particularly insightful. 

“Instead they simplify the complexity of diet to a handful of foods high in fibre without appreciation of important nuances,” they wrote, adding that scientists have not been able to define the optimal microbiome yet.

Cassidy says further research should focus on the differences in individual gut microbiomes. This could help explain why not everyone gets the same health benefits from eating flavonoid-rich foods. 

By understanding these mechanisms, nutritionists could offer personalized dietary plans based on individual microbiome responses. This means the future of nutrition may move beyond one-size-fits-all recommendations.