A new study, published in Hypertension, says that flavonoid-rich foods appear to have beneficial effects on Blood Pressure, explained in part by gut microbiome characteristics.

Flavonoids are naturally available in fruits, vegetables, and plant-based foods such as tea, chocolate, and wine that have been demonstrated to provide a variety of health advantages to the body in prior research.

The body’s gut microbiome — the bacteria that live in the digestive tract — helps to break down flavonoids. Recent research has established a relationship between gut microbiota, the microorganisms that live in the human digestive tract, and cardiovascular disease (CVD), the world’s leading cause of mortality.

Individuals’ gut microbiotas are highly varied, and there have been reports of changes in gut microbial composition among people with and without cardiovascular disease.

With growing evidence that flavonoids may help reduce the risk of heart disease, this study examined the involvement of the gut microbiome in the process. The researchers looked at the relationship between eating foods high in flavonoids and blood pressure and gut microbial diversity. Additionally, the study examined how much variation within the gut microbiome could account for the connection between flavonoid intake and blood pressure.

This study enrolled 904 persons between the ages of 25 and 82, 57 percent of whom were men, from Germany’s PopGen biobank.

At regular follow-up exams, the researchers assessed the patients’ food intake, gut microbiome, and blood pressure levels, as well as other clinical and molecular phenotyping.

The previous year’s intake of flavonoid-rich foods was determined using a self-reported dietary questionnaire that included the frequency and quantity of 112 types of foods consumed. Foods were assigned flavonoid values based on data from the United States Department of Agriculture on flavonoid content in foods.

The individuals’ gut microbiome was evaluated using faecal bacterial DNA isolated from stool samples. After a five-minute rest period, participants’ blood pressures were monitored three times in three-minute intervals following an overnight fast. Additionally, researchers collected information about participants’ lifestyles, including gender, age, smoking status, medication use, and physical activity, as well as family history of coronary artery disease, daily calorie and fiber intake, and each participant’s height and weight to calculate BMI (body mass index).

The analysis of flavonoid intake in relation to the gut microbiome and blood pressure levels revealed the following:

• The researchers discovered that participants who consumed the most flavonoid-rich foods, such as berries, red wine, apples, and pears, had lower systolic blood pressure and a more diverse gut microbiome than those who consumed the least flavonoid-rich foods.
• The diversity of the individuals’ gut microbiome could account for up to 15.2 percent of the link between flavonoid-rich meals and systolic blood pressure.
• Consuming 1.6 servings of berries per day (one serving equals 80 grams, or 1 cup) was related with an average 4.1 mm Hg drop in systolic blood pressure, with gut microbiota characteristics accounting for around 12 percent of the connection.
• Consuming 2.8 glasses (125 ml of wine each glass) of red wine per week resulted in an average 3.7 mm Hg reduction in systolic blood pressure, 15 percent of which might be attributed to the gut microbiome.

While this study reveals that red wine may have some health benefits, the American Heart Association advises against starting if you haven’t previously. If you do drink, consult your physician about the benefits and hazards of moderate alcohol consumption. According to an American Heart Association statement on dietary health, alcohol consumption can be a part of a healthy diet if it is consumed in moderation (no more than one alcoholic drink per day for women and two alcoholic drinks per day for men) and only by nonpregnant women and adults when there is no risk to pre-existing health conditions, medication-alcohol interactions, personal safety, or work.

The authors highlight that the study’s participants were drawn from the general public and were uninformed of the premise. However, because residual or unmeasured confounding variables (such as other health issues or genetics) can introduce bias, these data cannot establish a clear causal relationship, even though the researchers adjusted for a wide variety of food and lifestyle factors in their studies. The authors stress that this study focused on specific meals that were high in flavonoids, not on all foods and beverages that included flavonoids.

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