Can chocolate benefit your health?

One of the best pieces of medical news to emerge over the last several years is that chocolate may help you live longer, probably through a reduction in cardiovascular events like heart attack and stroke. But which type of chocolate is really the healthiest and how much chocolate should you be eating, before its advantages are cancelled out by overindulgence?  

Chocolate has been used for medical effect for thousands of years, but its status as a heart-healthy food was launched in the 1990s by Harvard Medical School researchers studying the Kuna Indians, living off the coast of Panama. The Kunas suffer very little hypertension, even with increasing age, despite their high salt intake. They also lived longer than their mainland cousins, with low rates of cardiovascular disease and cancer. Concluding the major difference in this indigenous population is dietary, the researchers focused their attention on the Kunas' regular consumption of cocoa - up to 5 cups a day - for clues about the effects of this largely unprocessed food. There’s a big difference between the cocoa the Kunas drink, and the cocoa and chocolate people usually purchase in a grocery or specialty store - mostly due to how it’s processed and its formulation.

Processing: Cocoa beans grow as the seed of the berry-like fruit of the cacao tree. After shelling and roasting, the beans are ground into a suspension called cocoa liquor, made up of cocoa butter (fat) and solids. Pressing removes most of the cocoa butter, resulting in a hard, dry cake, which is ground into what we use as cocoa powder.

This powder contains most of the flavanols, a family of flavanoids, or antioxidants that have since been credited with most of chocolate’s health benefits. Flavanols affect the way nitric oxide is produced in the body, helping blood vessels to relax, and thereby improving blood flow to the heart, the brain, and extremities. They also may reduce inflammation and the proliferation of dangerous free radicals produced in regular cell metabolism.

At this stage, cocoa powder remains quite bitter. As a result, it’s often processed by treatment with alkali -- most commonly sodium bicarbonate, or baking soda -- to make it darker, less acidic, and easier to mix into beverages. Unfortunately, this 200-year-old method, also known as "Dutch-processing," has been shown to destroy the active flavanol content by as much as 80%. Thus, the percentage of cocoa contained in a piece of chocolate, whether it’s 60%, 70% or higher, is no indication of its flavanol content.

Formulation: Cocoa butter has the unique property of having a melting point that matches human body temperature –- allowing it to literally “melt in your mouth” –- which makes it delicious. Its fat content, however, puts chocolate-lovers at risk of weight gain if they don’t compensate for those calories elsewhere. A 100g bar of chocolate contains more than 500 calories (compared with just 12 calories in a tablespoon of unsweetened cocoa). Obesity increases the risk of cardiovascular disease, diabetes, and cancer, so don’t try to extend your life by eating chocolate if it results in gaining weight. A very small amount of chocolate, perhaps only half a single square of a typical 100g dark chocolate bar may be sufficient for improved longevity.

Bottom line: Research on the indigenous Kuna Indian population of Panama suggests that unprocessed cocoa may be the healthiest form, due to its high flavanol content. Since flavanols are destroyed through chemical Dutch-processing, or alkalization, look for cocoas labeled "natural," as they have not been treated with alkali.

Source: Andres-Lacueva C., et al. “Flavanol and flavonol contents of cocoa powder products: influence of the manufacturing process.” J Agric Food Chem. 2008. May 14;56(9):3111-7. Epub 2008 Apr 16; Claims About Cocoa; Kenneth B. Miller et al. Impact of Alkalization on the Antioxidant and Flavanol Content of Commercial Cocoa Powders. J. Agric. Food Chem., 2008, 56 (18), pp 8527–8533; Norman K. Hollenberg, MD, PhD and Naomi D.L. Fisher, MD. “Is It the Dark in Dark Chocolate?” Circulation.2007; K. Hollenberg N. Vascular action of cocoa flavanols in humans: the roots of the story. J Cardiovasc Pharmacol. 2006.

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