Friday, December 5, 2014

Chocolate - A Holiday Update

The first people known to have made chocolate from the cacao tree were members of the ancient cultures of Mexico and Central America. The Maya and Aztec people took the tree from the rainforest - they harvested, fermented, roasted and ground the seeds into a paste. When mixed with water, chile peppers, cornmeal and other ingredients, this paste made a frothy spicy chocolate drink. The word ‘chocolate’ comes from a combination of the terms ‘choco’ (foam) and ‘atl’ (water).
*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 to 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 flavonoid content and the total antioxidant capacity have been shown to increase in plasma after cocoa consumption.
*The University of Michigan has summarized the benefits of dark chocolate as follows:
*Decreases LDL (“bad”) cholesterol oxidation
*Reduces the risk of blood clots
 *Increases blood flow in arteries and the heart
*May lower high blood pressure
*Cocoa may have a beneficial effect on cholesterol levels because it consists mainly of stearic acid and oleic acid. Stearic acid is a saturated fat, but unlike most saturated fatty acids, it does not raise blood cholesterol levels. Oleic acid, a monounsaturated fat, does not raise cholesterol and may even reduce it.
*May improve mood and pleasure by boosting serotonin and endorphin levels in the brain
*Regular intake is associated with better cognitive performance in the elderly
*Contains a number of minerals, including calcium, magnesium, and potassium
*CocoaVia by Mars The Mars company has been studying the health benefits of chocolate for over a decade, and has 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. CocoaVia is available in some stores and on line, in an unsweetened version as well as in a bar.  As far as I know, CocoaVia products are not labeled as organic or fair trade. 
*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.  Do not let your dog eat chocolate – dogs cannot metabolize theobromine and can develop epilepsy, have a heart attack or die from eating it.
*Oxalates – Chocolate is a source of oxalates, which can be a problem for people who have had calcium oxalate kidney stones.  If you are at risk, talk to your doctor – and drink lots of water!
*Healthy Chocolate for You! You can buy organic, fair trade, dark chocolate bars locally, and in many markets.  Look for a bar that has 70% cocoa or higher.  Note the caloric content if you are watching your weight.  You can also find unsweetened cocoa powder, and make sure it is not ‘dutch processed’, which will lower its flavonoid content. Make a cocoa drink with 1% milk, soy or nut 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 or almond 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