Chocolate Packed with Heart-Healthy Components

Chocolate's flavonoids, theobromine and other components go right to the heart.

By David Feder, R.D., Managing Editor

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With most chocolate consumed from Christmas through Easter, by the time spring is in full bloom — 150 million chocolate Santa Clauses, 36 million boxes of chocolate hearts and 90 million Easter bunnies later — many of us feel at least some measure of chocolate-covered guilt. But like those aforementioned confections, the guilt may turn out hollow. At least partly.

While it's true overindulgence in any sweet is not a healthy thing, cocoa and chocolate are staking out more and more territory in the domain of functional foods — foods that contain compounds such as phytochemicals, which are believed to provide a health benefit beyond basic nutrition. And that's good news, considering Americans spending nearly $15 billion to eat almost 3.5 billion pounds of the seductive substance each year, according to Susan Smith of the Chocolate Manufacturers Assn., McLean, Va.

Cocoa, derived from the cacao tree, is the result of processing fermented, dried cocoa beans. The dried beans are roasted and ground, creating a high-fat chocolate "liquor." If this liquor is allowed to cool and solidify, the result is plain, unsweetened chocolate (often sold as baking chocolate).

If the liquor is pressed to separate and remove the fat, the resulting products are cocoa and cocoa butter. Each of these may, in turn, be combined with other ingredients to make confections such as chocolate bars or further processed into cocoa powder or hot chocolate mixes. Cocoa butter also is used in other food products and cosmetics.

Chocolate has a centuries-old association with health and energy, going back to ancient Mesoamerica and the Aztecs. But modern science, too, has spent decades looking at the compounds in chocolate to back up the lore.

A number of compounds in the classes called flavonoids and flavonols found in cocoa products, including dark and milk chocolate, show evidence of contributing to the maintenance of heart and vascular health. Flavonoids and flavonols also are found in tea, apples, grapes and a host of other plant foods. These compounds, which include catechins, epicatechins and procyanidins, have also been linked to protective effects against other diseases, such as cancer and urinary tract infections.

Theobromine for high blood pressure

Another natural cocoa component also associated with health is the caffeine "cousin" theobromine. Theobromine is an alkaloid in the class of compounds called xanthines or, more specifically, methylxanthines, which include caffeine and theophylline (also in chocolate, as well as in tea).

Theobromine has some effects similar to caffeine. It is a mild diuretic (stimulates urine production), a mild stimulant and relaxes the muscles of the lungs' bronchial pathways. Concentrated theobromine is sometimes used clinically as a diuretic, particularly in cases of cardiac failure. It's also been used in clinical settings for its vasodilation properties (ability to dilate blood vessels). This has made theobromine a useful treatment for high blood pressure.

One study generating a sweet surge of excitement was last fall's discovery that theobromine, at least in tablet form, was nearly one-third more effective than codeine for treating a persistent cough. The research, conducted at Imperial College London and published in the Federation of American Societies for Experimental Biology (FASEB) journal, found theobromine suppressed the vagus nerve activity responsible for causing coughing. The theobromine worked better than codeine against induced coughs in volunteers and caused no adverse effects. The study was small, but the results certainly encourage further investigation.

Theobromine amounts differ with the type of chocolate. The darker and higher the quality of chocolates — that is, chocolates from richer beans and higher cocoa content — the higher the levels of theobromine and, in fact, the other beneficial phytochemicals.

In some cases, chocolate has proven to be richer in these healthful compounds than other foods usually associated with good health. For example, dark chocolate has more flavonoids than green and black tea, red wine and even blueberries.

Rich in flavonoids

Scientists seeking the chocolate bullet of health have spent years looking at the flavonoid group of chemicals as being especially important. One recently described flavonoid, epicatechin, was discovered to be exceptionally beneficial to vascular function and is considered key to the beneficial effects of chocolate on the inner linings of blood vessels.

Flavonoids, long recognized as powerful antioxidants, are found in a variety of plants. Their beneficial effects read like a who's who of cardiovascular system support, including properties such as suppressing blood platelet aggregation, regulating inflammatory action, inhibiting atherosclerosis, decreasing LDL cholesterol and decreasing the body's inflammatory immune responses.

New studies back up earlier research showing the antioxidants in dark chocolate and cocoa powder may increase HDL (so-called "good") cholesterol by as much as 10 percent and reduce LDL cholesterol oxidation, a process that normally leads to artery-clogging plaques. All these favorable functions mean chocolate may reduce risks for strokes or heart attacks.

Chocolate is not bad, and it may have beneficial effects, according to Penny Kris-Etherton, Ph.D., R.D., at Pennsylvania State University. "People should not feel guilty about including chocolate — especially cocoa powder and dark chocolate — as a part of a balanced and healthy diet. Moderation is the key," says Kris-Etherton, whose own research has contributed significantly to understanding chocolate's role in health.

Best of all, most studies on chocolate (one exception being the theobromine and cough suppression study, above) focus on amounts which folks can enjoy with relative impunity: a few ounces or less daily.

For example, Kris-Etherton's studies involved feeding subjects as little as 16 g (about half an ounce) of cocoa powder. An ounce or two is the common amount tested in many of the human trials, and a small study recently conducted at the Hippokratian Hospital at the University of Athens found eating about 3.5 ounces daily (100 g) of dark chocolate improved blood vessel function in healthy young adults for three hours or longer.

The study was a follow-up to an American study, published in the June 2004 Journal of the American College of Nutrition, that found that flavanoids appeared to increase dilation of blood vessels. That study looked at samples of cocoas with varying flavonoid levels, with the samples provided by the American Cocoa Research Institute. A healthy increases in vascular dilation usually means better circulation and fewer chances of clot formation, protecting the body against thrombosis, stroke and cardiac incidents.

A February 2003 review in the Journal of the American Dietetic Association regarding potential health aspects of flavonoids found in cocoa and chocolate described a variety of beneficial actions, such as antioxidant protection and blood flow regulation.

Positive benefits to cardiovascular health also were reported for other constituents in cocoa. Although chocolate is high in fat, cocoa butter is about one-third stearic acid, a fat known to positively influence blood cholesterol levels. The association also noted cocoa and chocolate contribute needed trace minerals, especially those critical to vascular tone. The ADA review concluded "multiple components in chocolate, particularly flavonoids, can contribute to the complex interplay of nutrition and health."

For processors, adding these healthy flavonoids to foods may pose a problem due to their characteristic bitterness. But scientists found adding flavonoids to foods at beneficial levels may not necessarily increase bitterness and even could improve the taste of some products. The antioxidant ability of flavonoids acts as a protector of flavor for foods that are heat-treated.

At a recent meeting of the American Chemical Society, several successful experiments with epicatechin (one flavonoid found in chocolate) were described. In one, ultrapasteurized milk containing the compound was protected from developing an off, "overcooked" flavor, and taste testers could not detect a difference in flavor of pasteurized milk with added epicatechin.

Another experiment discussed at the meeting described how in a granola bar the flavonoid inhibited formation of negative flavors associated with processing without any increase in bitterness. In a third study presented at the meeting, epicatechin was added to unroasted cocoa, which was then heat processed. The addition of epicatechin halved the formation of two known negative flavor elements. The scientists concluded these flavonoids can be included during food processing without increased bitterness, allowing processors to make healthier, tasty foods.

For more information on the functional compounds in chocolate and other foods, check out the International Food Information Council's functional foods comprehensive information update at http://ific.org/nutrition/functional/index.cfm.

   
MEDICINE OR OPIATE?

Neuropharmacologists searching for the chemistry behind the universal passion for chocolate discovered marijuana-like compounds, called cannabinoids, in the confection, plus related chemicals that could help in the treatment of depression and other ailments.

At the University of Michigan, Adam Drewnowski, director of human nutrition, determined chocolate may possess natural analgesic properties, and eating chocolate may trigger the brain's production of natural opiates.

In a study reported in Nature, researchers identified several compounds in chocolate that act independently of fat and sugar in their ability to enhance the sense of pleasure and well-being. Based on evidence that nerve cells in the brain produce anandamide — a chemical that activates the same cellular receptors as THC in marijuana — the research group found n-oleoylethanolamine and n-linoleoylethanolamine in trace amounts in chocolate.

In in vitro trials, these chemicals were shown to delay anandamide's breakdown. This suggested an ability to prolong the pleasurable sensations derived from the body's own natural production of anandamide.

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