Almonds, Blueberries, and Oat Bran Help, Too

Dark Chocolate provides improved cardiovascular function and lowered risk for heart disease, according to a report in the Journal of the American College of Nutrition.

Dr. Mary Engler, a professor of physiological nursing at the University of California, San Francisco School of Nursing, says that eating dark chocolate can make arteries expand, increasing blood flow, and thus reducing cardiovascular risk.

Milk chocolate does not provide the same protection, Dr. Engler stresses, because it is, well, too milky. Look for darker chocolates, because darkness is an indicator of high levels of flavonoids, the chemicals that loosen up the arteries.

Flavonoids are naturally-occurring compounds found in plant-based foods. According to the Chocolate Information Center, supported by Mars, Inc., scientists have discovered that one of the functions flavonoids may have is to act as antioxidants in humans.

Antioxidants are believed to help the body's cells resist damage by free radicals, which are formed by numerous processes including when the body's cells utilize oxygen for energy.

Tastes Good, Supports Health

You can tell that a chocolate has a high flavonoid content because "the flavor is so intense and rich," Dr. Engler says.

Dr. Engler and her colleagues asked 11 willing participants to eat 1.6 ounces of flavonoid-rich chocolate every day for two weeks. Another 10 volunteers consumed an equal amount of low-flavonoid chocolate.

Ultrasound measurements showed that expansion of the arteries in response to greater blood flow increased by 10 percent in the flavonoid consumers, while there was a slight decrease in those who got the flavonoid-poor chocolate.

Blood levels of a powerful flavonoid, epicatechin, rose more than eightfold for the high-flavonoid group and remained unchanged for the others.

The study was conducted in collaboration with the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University.

Flavonoids Found in a Variety of Foods

Dr. Jeffrey Blumberg, chief of the center's Antioxidant Research Laboratory, said the work has expanded to look at other flavonoid-containing foods.

"Not only chocolate, but also tea, oat bran, almond skins, and blueberries, all are good sources of flavonoids," Dr. Blumberg said. "We're trying to get a better understanding of vital chemicals, flavonoids being one of the larger groups."

Dark chocolate "happens to be a rich source of flavonoids," Dr. Blumberg said, but he adds that "we are not trying to position chocolate as a health food."

In addition to flavonoids, chocolate also has a lot of calories and a lot of saturated fat, neither of which is good for the arteries, he says.

"But in the context of a reasonable diet, chocolate is not only a pleasurable food but might contain some health-promoting ingredients," Dr. Blumberg says.

Recommendations about dark chocolate can be compared with those about wine, Dr. Engler says.

An occasional glass or two of wine has been shown to be associated with a reduced risk of cardiovascular disease, she says, "but people should not be overindulgent with wine. The same is true of dark chocolate in moderation as part of a well-balanced diet."

Always consult your physician for more information.

Online Resources

Centers for Disease Control and Prevention (CDC)

Chocolate Information Center, Mars Inc.

HealthierUS.Gov

National Institutes of Health (NIH)

National Library of Medicine

National Women's Health Information Center

Office of Research on Women's Health

US Food and Drug Administration

July 2004

Dark Chocolate Aids In Cardiovascular Health

Tastes Good, Supports Health

Flavonoids Found in a Variety of Foods

What Are Flavonoids?

Plants Benefit From the Cocoa, Too

Online Resources

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What Are Flavonoids?

According to the American Heart Association (AHA), flavonoids are compounds with varied chemical structures present in fruits, vegetables, nuts and seeds.

The major flavonoid categories are flavonols, flavones, catechins, flavanones, and anthocyanins.

The main dietary sources of these compounds are tea, onions, soy, and wine. The main flavonoid in onions is quercetin glucoside and the main flavonoid in tea is quercetin rutinoside.

The AHA states that flavonoid intake has been inversely linked with coronary heart disease in the Zutphen Elderly Study, the Seven Countries Study, and a study in Finland.

That is, people with a low intake of flavonoid had a higher death rate from coronary heart disease than did those who consumed more flavonoid (about five to six cups of tea per day).

The AHA states that some flavonoids have toxic effects (gastrointestinal or allergic), especially if taken in large amounts.

More study is needed on the major classes of flavonoids to understand their structure, effectiveness, and potential harmful effects, the AHA states.

The link between flavonoids and atherosclerosis is based partly on the evidence that some flavonoids have antioxidant properties. For example, the phenolic substances in red wine inhibit oxidation of human LDL.

Flavonoids also have been shown to inhibit the aggregation and adhesion of platelets in blood, which may be another way they lower the risk of heart disease.

Isoflavones in soy foods have been reported to lower plasma cholesterol and also to have effects similar to estrogen.

Always consult your physician for  more information.

Plants Benefit From the Cocoa, Too

Flavonols play an important protective role in the cacao plant, according to the Chocolate Information Center.  

The Center states that compounds created naturally to protect the health of the plant may also help to maintain the health of humans as well.

Research suggests that flavonols work two ways to protect plants - they contribute to the healing of wounds and use antimicrobial properties for protection against disease.

Flavonols can either be present in the plant at the time of the injury or can be produced in response to the injury.