About 45% of Americans have high blood pressure, or hypertension, according to the Centers for Disease Control and Prevention. Yet only 1 in 4 has it under control, which leaves the majority at an increased risk of heart attack, stroke and kidney failure. Now, a new British study of 25,000 people reports that a diet rich in compounds called flavanols may help reduce blood pressure. And the higher a person’s blood pressure is, the more effective flavanols may be.
The study was funded by the Medical Research Council and the National Institute for Health Research in the U.K. and Mars, the maker of M&M's and other candy brands. Mars is also the employer of two of the study authors.
What are flavanols, anyway?
Even though you might not have heard of flavanols before, you probably consume them every day. These naturally-occurring compounds are found in lots of plant-based foods and drinks, especially:
- Apples and pears
- Broccoli, spinach and kale
- Onions and scallions
- Red wine
How do flavanols help with blood pressure?
“Flavanols may improve blood pressure by favorably impacting the hormones that regulate and control blood pressure,” Howard Sesso, an associate professor of epidemiology at the Harvard T.H. Chan School of Public Health in Boston, who was not affiliated with the study, told TODAY. However, foods can vary wildly in their flavanol content. Take tea for example, which can contain anywhere from 10 and 600 milligrams of flavanols per cup. Because of this, researchers usually estimate flavanol consumption by asking people to recall everything they typically eat. That has a big downside.
“Self-reporting always relies on study participants to remember and record their food intakes correctly,” said Gunter Kuhnle, a professor of food and nutritional sciences at the University of Reading outside of London, who led the study. “But we know from many previous studies that this is not always the case, especially since people usually over-report eating foods they think are healthy yet underreport those that aren’t as good for them.”
This study was different. In addition to scrutinizing people’s diets, researchers also measured markers of flavanol consumption in the volunteers’ bodies. “Nutritional biomarkers, such as those evaluated in this study, are more objective and have the potential to provide high-quality evidence for nutrients on blood pressure and other outcomes,” said Sesso. So even though this is not the first study to find a link between flavanol intake and lower blood pressure, it may be the most accurate.
How effective are flavanols?
The study participants who consumed the most flavanols had blood pressure readings that were 2 to 4 mmHg lower than those who took in the fewest flavanols. That’s similar to the reduction a person would achieve by following the Mediterranean diet or the DASH diet. But it’s not as much as the roughly 10mmHg drop that a person would get from taking antihypertensive medication, says Kuhnle. Better blood pressure, however, isn’t the only reason to eat more flavanol-rich foods. These potent compounds may also protect against Alzheimer’s disease and they’ve been linked to improved memory, attention and mental processing.
What are the best blood pressure-lowering foods?
In this study, volunteers obtained most of their flavanols from apples, tea, red wine, berries and chocolate. Does that mean it’s okay to load up on chocolate? Not exactly. “It’s important to note the difference between cocoa and chocolate,” says Sesso. “Cocoa is a rich source of flavanols, but chocolate is not, as cocoa flavanols are often destroyed during chocolate processing.” Perhaps that’s why a recent study found that eating cocoa-rich chocolate has no impact on blood pressure or other markers of heart health.
A better strategy? Eat lots and lots of fruits and veggies. Not only are they packed with flavanols, they also deliver plenty of other blood pressure-lowering nutrients like potassium, magnesium and calcium.