Antioxidant compounds called flavonoids are key to the remarkable health benefits of many fruits and vegetables, and even red wine.

For instance, researchers have discovered that flavonoids can fight inflammation and protect your heart. Recently they made another discovery: The heart health benefits of flavonoids may be the result of a process that happens in your digestive tract.

Here’s the fascinating story and what it means for your diet and supplement regimen.

Flavonoids are becoming well known for their heart health benefits, which include a reduced risk of high blood pressure and cardiovascular disease.

Flavonoids are just one of many chemical groups found in plants known to have a broad spectrum of health-promoting effects. Flavonoid-rich foods and beverages include berries, apples, pears, grapes, bell peppers, dark chocolate, tea and red wine.

Many studies show higher intakes of flavonoids significantly reduce the risk of heart disease, and one also found it lowered the risk of death from heart disease. (Risk of developing a disease and risk of death from it are different variables.) One type of beneficial flavonoid is also linked to lower blood pressure.

Anthocyanins Lower Blood Pressure

Anthocyanins are one of six subclasses of flavonoids. They are found in high concentrations in blackcurrants, blackberries, blueberries, red cabbage, cranberries and cherries.

One very large study showed that adults consuming diets with the highest 20 percent of anthocyanin intake had an eight percent reduced risk of hypertension over 14 years compared to the lowest 20 percent. Another showed anthocyanins reduced arterial stiffness and lowered systolic (upper) blood pressure by three to four mm Hg.

Why are flavonoids so effective at helping your heart? Scientists believe it might have something to do with the bacteria in your gut.

Following ingestion most flavonoids interact with the gut microbiome, causing structural changes to both. For instance, anthocyanins increase levels of beneficial bifidobacteria. At the same time these beneficial bacteria form metabolites within the gut which are believed to be even more cardioprotective than the anthocyanins themselves.

This interaction between flavonoids and gut bacteria led to a unique study that shed new light on the importance of gut health.

Simple Dietary Changes Have Profound Benefits

Researchers looked at data on 904 participants aged between 25 and 82. Each filled out a food frequency questionnaire. In addition, the researchers analyzed their gut microbiome using fecal samples and measured their blood pressure.

Information was also collected on age, gender, smoking status, physical activity, calorie and fiber intake, body mass index, medications and family history of heart disease.

Taking all of these factors into account, the researchers discovered those consuming the most flavonoid-rich foods had lower systolic blood pressure and greater gut microbiome diversity than participants consuming the lowest levels of flavonoids.

Up to 15.2 percent of the link between flavonoid-rich foods and systolic blood pressure was explained by gut microbiome diversity. For instance, eating 128 grams/4.5 ounces of berries containing 112 mg of anthocyanins per day reduced systolic blood pressure levels by an average of 4.1 mm Hg, and about 12 percent of the association was explained by gut microbiome factors.

Drinking 2.8 glasses (125 ml of wine per glass) of red wine a week lowered systolic blood pressure by an average of 3.7 mm Hg, of which 15 percent could be explained by the gut microbiome.

Lead study investigator Aedín Cassidy explained, saying, “Our gut microbiome plays a key role in metabolizing flavonoids to enhance their cardioprotective effects, and this study provides evidence to suggest these blood pressure-lowering effects are achievable with simple changes to the daily diet.

“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.”

My Takeaway

We’ve long reported on the importance of the gut microbiome and maintaining a healthy balance of bacteria in your journey to achieve optimum health. Studies have shown that a healthy gut can improve your immune system, protect your memory, help you maintain a healthy weight and, yes, support the health of your heart and arteries.

This new study adds weight to the advice of many natural health doctors to keep your gut in working order by exercising, eating a healthy diet rich in fruits and vegetables and supplementing with healthy probiotic bacteria.

As the science evolves, researchers will no doubt learn more about how the gut microbiome interacts with the nutrients you consume to bring about positive changes in your health. I’ll keep you posted.


  1. https://newsroom.heart.org/news/gut-bacteria-and-flavonoid-rich-foods-are-linked-and-improve-
    blood-pressure-levels?preview=fa05
  2. https://www.ahajournals.org/doi/10.1161/HYPERTENSIONAHA.121.17441