Updated February 04, 2015.

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Question: Does Cocoa Content Matter in Dark Chocolate?

Chocolate has been shown in a number of studies to benefit longevity, thanks primarily to a reduction in cardiac problems like heart attack and stroke. As chocolate-lovers learn more about the health benefits of their favorite treat, many gravitate towards the darkest varieties. But does a higher percentage of cocoa in your chocolate guarantee that it will deliver all the heart-healthy effects you're seeking?

Answer:

The degree of processing of the cocoa used to make each chocolate bar may well be more important than the percentage of cocoa displayed on the label, concluded Harvard Medical School researcher Norman Hollenberg, following his team's investigation of the Kuna Indians of Panama. Back in the 1990s, Hollenberg studied how the Kunas consistently had low blood pressure, despite consuming a lot of salt. This was true even as they got older — also unusual, since hypertension often increases with advancing age. In the United States, for example, about 65% of adults over the age of 60 have high blood pressure, according to the National Heart, Lung, and Blood Institute.

The Kunas' diet includes drinking several cups of unprocessed cocoa a day. Typical processing of cocoa involves treating the cocoa powder extracted from roasted beans with an alkali such as sodium bicarbonate, or baking soda. Such treatment can destroy the concentration of flavonols, a group of antioxidants believed to be responsible for chocolate's health benefits.

In a 2007 editorial in the journal Circulation, Hollenberg argued for flavonol content to appear on chocolate labels, rather than the true percentage of cocoa, as a more meaningful measure of its healthy ingredients.

Until such a time as when labeling requirements change, read the label if you are using cocoa in cooking or baking. Sodium bicarbonate as an ingredient indicates the powder has undergone alkali processing, so consider choosing a "raw" or "natural" cocoa product (such as cacao nibs) to maximize the antioxidant content of your favorite cocoa concoction.

• Read More: What's the right "dose"?
• Can chocolate be slimming?
• Chocolate as Medicine Throughout History

<sub>Sources:

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. DOI: 10.1021/jf801670p.

Norman K. Hollenberg, MD, PhD and Naomi D.L. Fisher, MD. “Is It the Dark in Dark Chocolate?” Circulation. 2007; 116: 2360-2362.
http://circ.ahajournals.org/content/116/21/2360.full

Who Is At Risk For High Blood Pressure? US National Heart, Lung, and Blood Institute Public Information Sheet. Accessed February 11, 2013.
http://www.nhlbi.nih.gov/health/health-topics/topics/hbp/atrisk.html</sub>