Diet High in Flavanol May Lower Blood Pressure, Study Finds

Foods such as red wine and apples have been highlighted for cardiovascular benefits before, and a new study in Nature suggests this may be because they have high levels of bioactive compounds that could improve vascular function.??

Known as flavan-3-ols or flavanols, these compounds may lower blood pressure with the same efficacy as other food-related changes such as adopting a Mediterranean diet approach or moderating salt intake, the study suggests.

Eat More Apples, Drink More Tea

The study was based on data of 25,618 men and women, with results linked to the amount of flavanols found in participants' systems and their blood pressure readings.

Researchers also looked at associations between flavan-3-ol levels and other cardiovascular risk markers like blood lipids and c-reactive protein, but found only modest improvements with those.

Since the connection to low blood pressure was significant, though, they concluded that higher intake could affect overall cardiovascular function and mortality.

Foods and beverages known to be high in the compound are:??

• Green, white, black, and oolong tea
• Grapes
• Wine
• Apples
• Berries
• Cocoa

These are not the same compounds as flavonols, although both types fall under the family of compounds known as flavonoids. Flavonols, which also have numerous benefits, are found in foods like onions, scallions, kale, and broccoli.

How This Research Is Different

Nutritional studies are notoriously tricky for several reasons, says study co-author Gunter Kuhnle, Ph.D., in the Department of Food and Nutritional Sciences at the University of Reading in the UK.

"If research is based on self-reporting, it runs into the issue of participants incorrectly logging or recalling what they ate, and leaning more toward reporting healthier selections than they may have had," he says. More difficult to address is when researchers are trying to determine the effects of individual compounds like vitamins and minerals as well as caffeine or flavanols.

"The variability in food composition is huge, even in foods harvested from the same plant," says Kuhnle. For example, apples harvested from the same tree may be very different in terms of their vitamin C content, even if they're roughly equal in size.

"Also, composition changes during storage and, of course, preparation." This means it's very difficult to estimate the actual intake of a compound based on dietary data and food composition, he adds.

But this problem can be addressed by looking at biomarkers, which means measuring what is taken up by the body, and can indicate exactly what a person has consumed. When combined with a large dataset and a longer duration in terms of timeframe, it can run counter to the usual nutritional study limitations.

That's the approach done with the recent large-scale study, which took almost 10 years to complete. In examining how the body metabolizes flavanols, researchers were able to get an accurate estimate of intake from urine samples.

"The results of the study are exciting," Kuhnle says. "Because for the first time, we can show that there was a statistically significant, meaningful difference in blood pressure between those high- and low-flavanol intake."

Effect on Blood Pressure

The most likely reason for the benefits with blood pressure is because flavanol itself contains a compound, catechin. This is a natural antioxidant and can lower inflammation. Not only is it good for your heart, but it can also offer major benefits throughout your body, and even impact your brain.

For example, a recent study published in Aging suggests that consistent tea drinkers have healthier cognitive function and better organized brain regions compared to non-tea drinkers, mainly because of tea's high level of catechin, according to study co-author Junhua Li, Ph.D, of the University of Essex.??

"The compound not only lowers blood pressure, which is beneficial for brain health, but the compounds like catechin actually improve connections between brain regions," he says.

In addition to drinking tea and having other flavanol-packed food and beverage choices, there are other ways to lower blood pressure as well:

• Reduce stress
• Get more quality sleep
• Exercise regularly
• Lose weight if needed