Tea, Berries, and Other Flavanol-Rich Foods May Help You Manage Hypertension

A diet rich in flavanol-containing foods and drinks, including tea, apples, and berries, could help lower blood pressure, according to a recent study.  

“These findings are incredibly exciting,” Elise Compston, RD, LD, a Reno, Nevada-based registered dietitian, tells Verywell. She was not involved with the research. “The fact that improvements were seen by simply including flavanol-rich fruits and tea in the diet should give encouragement to those looking to make simple lifestyle changes to support their health.”

The October study, published in Scientific Reports, evaluated the intake of over 25,000 subjects in the U.K. and determined whether there was a link between their blood pressure and what they ate. But instead of using self-reported diet as a way to gather data, the researchers used nutritional biomarkers found in blood. This is because the variability of flavanol content in food makes it challenging to rely solely on dietary reporting to assess intake. 

Researchers found that higher levels of flavanol, a naturally-occurring compound, were associated with a significantly lower systolic blood pressure in both men and women. The levels were comparable to adherence to a Mediterranean diet or moderate salt reduction.

Subjects considered to be hypertensive had a stronger inverse association between flavanol levels and systolic blood pressure when compared to those who were not considered to be hypertensive, suggesting the effects are stronger in those with this diagnosis.

However, the researchers did not observe consistent or statistically significant association between flavanol intake and heart attack or death.

What Are Nutritional Biomarkers?

According to the researchers, it's almost impossible to estimate flavanol intake without analyzing the actual food consumed. But self-reported dietary data like a dietary recall or a food frequency questionnaire can be unreliable in certain situations, Melissa Azzaro, RDN, LD, a registered dietitian in New Hampshire and author of A Balanced Approach To PCOS, tells Verywell.

She explains that people have a hard time recalling what they eat accurately—or sticking to their normal eating habits—when they know they're being tracked. "When tracking foods knowing that our diet is going to be looked at by a professional, it can impact our choices,” Azzaro says. You might be less likely to eat a donut for breakfast instead of a more balanced meal if you know you'll have to tell someone tomorrow.

This is where biomarkers can help.  

A nutritional biomarker is something that can be objectively measured in different biological samples and can be used as an indicator of nutritional status—with respect to the dietary intake or metabolism of nutrients. By taking a sample of blood or urine, levels of certain biomarkers—like flavanols—can be measured. No more relying on self-reported data.

In the case of this study, flavonol levels were measured through urine samples.

Flavonols and Hypertension

Common recommendations to manage high blood pressure include limiting salt, getting regular physical activity, and managing stress. But guidelines do not specifically include taking in a consistent amount of flavanols per day. However, the new data highlights a single compound’s potential positive role in the health of people with hypertension.

“We know from the DASH DIET (Dietary Approaches to Stop Hypertension) that what we eat is critical to managing blood pressure,” Lauren Harris-Pincus, MS, RDN, a New Jersey-based registered dietitian and author of The Protein-Packed Breakfast Club, tells Verywell. 

The standard DASH diet guidelines include:

• Eating vegetables, fruits, and whole grains
• Including fat-free or low-fat dairy products, fish, poultry, beans, nuts, and vegetable oils into your diet
• Limiting foods that are high in saturated fat, such as fatty meats, full-fat dairy products, and tropical oils such as coconut, palm kernel, and palm oils
• Limiting sugar-sweetened beverages and sweets
• Consuming up to 2,300 mg sodium per day 

Harris-Pincus adds that the new data reinforces that consuming foods rich in flavanols such as tea, cocoa, apples, and berries can positively impact hypertension and the risk of cardiovascular disease.

Following a flavanol-rich and DASH-compliant diet can go hand-in-hand, as many fruits naturally contain this important compound. The same goes for the Mediterranean diet, which has been shown to play a positive role in hypertension management as well.

“The addition of one or more servings of fruit per week, like apples and berries, has additional benefits—vitamins, minerals, phytochemicals, and soluble fiber, which has been shown to support a healthy heart,” Compston says. 

"Currently, only 1 in 10 Americans consume the recommended servings of fruits and vegetables per day," she says. "Fruits, vegetables, and teas also contain potassium, which has been shown to support the sodium-potassium ratio on blood pressure."

To help manage hypertension, you can enjoy a cup of tea, indulge in some blueberries dipped in dark chocolate for a decadent treat, or snack on a crunchy apple. Along with other healthy lifestyle changes like managing stress, avoiding cigarette smoking, and maintaining a healthy weight, incorporating flavanol-rich foods into your diet on a consistent basis could be the missing link in your overall health.