*Nitric Oxide (NO) Dr. Norman Hollenberg at Harvard University has studied the ability of cocoa to increase the amount of nitric oxide (NO) in the body. NO is a gaseous ‘signaling molecule’ that crosses membranes and freely diffuses between cells. It signals the muscular coating around arteries to relax, thus improving blood flow and lowering blood pressure. Several medicines are based on this effect - nitroglycerin is a vasodilator because it is converted to NO in the body and Viagra stimulates erections by the effects of NO on blood vessels in the penis. Another protective effect of NO on the cardiovascular system is its inhibition of blood clotting and the adhesion of white blood cells on the lining of blood vessels.
*Flavonoids – Flavonoids are a group of compounds found widely in plants that produce healthy effects on animals who eat them. Many flavonoids activate the nitric oxide system. Cocoa is one of the richest sources of flavonoids (although current processing techniques reduce the content), Dr. Hollenberg and colleagues in Panama studied the Kuna Indians who live off the coast of Panama; the Kuna drink lightly processed cocoa as their main beverage and therefore have one of the world’s richest diets in flavonoids. The Kuna do not show an increase of blood pressure with aging, or decline in kidney function. Their death rates from heart disease, stroke, diabetes and cancer are markedly lower than those of genetically similar Kuna in mainland Panama, where cocoa is replaced by local foods. The researchers wrote a paper on the Kuna, concluding that “the comparatively lower risk among Kuna in the San Blas islands from the most common causes of morbidity and mortality in much of the world, possibly reflects a very high flavanol intake and sustained nitric oxide synthesis activation. However, there are many risk factors and an observational study cannot provide definitive evidence.”
In the Dutch Zutphen Study, cocoa intake specifically was associated with a 50% reduced risk of cardiovascular mortality between the highest and lowest quintile of intake in 470 elderly men. These epidemiologic data led to the hypothesis that the health benefits of cocoa may be linked to its flavonoids. Both the flavanoid content and the total antioxidant capacity have been shown to increase in plasma after cocoa consumption.
*CocoaVia by Mars The Mars company has been studying the health benefits of chocolate for over a decade, and have isolated the particular flavonol in cocoa that relaxes blood vessels and inhibits clotting. Their formula for this - a trade secret - is in their chocolate bar CocoaVia, along with plant substances (sterols) that lower cholesterol. But there’s a big catch, reports the Harvard Heart Letter - the extra calories and saturated fat in these bars make them less desirable as a daily source of flavonols. A product called ‘Acticoa’ in Europe is said to have the same beneficial ingredients as the Mars bars, but is not available in the US.
*Theobromine Chocolate has a mild stimulating effect due to theobromine, a substance similar to caffeine. People sensitive to caffeine and parents of young children should be cautious about this, and avoid chocolate close to bedtime.
*Healthy Chocolate for You! You can buy organic, fair trade, unsweetened cocoa powder at natural food stores and some supermarkets. Make a cocoa drink with soy milk, 1% milk or hot water, and sweeten it with xylitol (a healthy sugar that’s good for your teeth!) or stevia or both. You can skip sugar by mashing a banana with unsweetened cocoa powder, and add peanut butter if desired. You can make a shake with your favorite ingredients and add cocoa powder and pomegranate concentrate for sweetness. Purists can buy organic, fair trade cocoa nibs and eat them with raisins for sweetness. Buying ‘fair trade’ cocoa or chocolate bars is important, because cocoa producers in Latin America are often badly underpaid and in Africa child labor is a serious problem. The fair trade label ensures that the cocoa workers are decently treated.
Sadja Greenwood, MD MPH, back issues on this blog