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Q. I've heard that chocolate may have health benefits. What are they? How can I tell which chocolates are best? Should I be eating more?
A. Many randomized, short-term, clinical trials found cardiovascular health benefits from consuming cocoa products, including decreased blood pressure, improved blood vessel function, and decreased insulin resistance. Some studies have noted increased blood flow to the brain, and a 2012 study published in Hypertension found improvements in cognitive function in a small group of elderly individuals.
While these results look promising, most studies were short-term, and many used specially formulated cocoa products containing high levels of epicatechin and catechin, flavanols that are also found in tea and red wine. It is not clear whether these results translate into cardiovascular disease protection over the long term or whether commercial chocolate bars offer similar benefits.
An intriguing study sheds light on the long-term effects of cocoa consumption. Kuna Indians living on an island in Panama and drinking large quantities of home-prepared cocoa have remarkably low blood pressure and minimal cardiovascular disease. Studies have linked these health benefits to consumption of the specially prepared cocoa rather than genetics, since relatives living on the mainland and drinking commercially prepared cocoa do not experience the same protective effect.
What is special about the Kuna's home-prepared cocoa? The drink is prepared from minimally processed cacao beans and is extremely rich in flavanols. Raw cacao beans are very bitter and are extensively processed to yield the chocolate we eat. This processing separates the cocoa solids, containing most of the beneficial nutrients, from cocoa butter, which has most of the fat. White chocolate, which is made from the cocoa butter, contains a very amount of flavanols. Furthermore, many of the flavanols may be destroyed in processing cocoa solids into dark chocolate, depending on the technique used.
For example, the Dutch process, where chocolate is treated with an alkalizing agent, is particularly destructive.
How can the consumer judge flavanol content of chocolate? It's not straightforward, since flavanol content is not listed on most chocolate products and, because of the various processing techniques, the percentage of cacao does not always correlate well with flavanol content. Nonetheless, studies investigating commercially available cocoa products found that, in general, unsweetened cocoa has a higher flavanol content than dark chocolate, which in turn has a higher flavanol content than milk chocolate.
This variability in flavanol content is reflected in the wide spread of values listed in the 2013 USDA Database for the Flavonoid Content of Selected Foods.
Given the large variability in flavanol content as well as the high fat and sugar content in many commercial chocolate bars, most experts warn against overindulging and suggest treating chocolate more like candy than medicine.
Teddie Keller volunteers with the Grillo Health Information Center, which offers free and confidential health research to consumers. Research or assistance is not medical advice. Contact the Grillo Center at 4715 Arapahoe Ave, by phone 720-854-7293, or at GrilloCenter.org. We encourage informed consultation with your physician or medical practitioner.