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 There are increasing reports that plant polyphenols with their antioxidant properties may offer protection against certain cancers and cardiovascular disease (CVD). Polyphenols include flavonoids, and a rich source of favonoids is cocoa. Chocolate and other products made from cocoa contain flavonoids such as catechin, epicatechin, and procyanidin. There is some evidence that cocoa has a protective effect on the cardiovascular system. Testing chocolate's effects Up until now, evidence for cocoa's protective effects came from two types of research. Test tube studies using extracts of cocoa or flavanols isolated from cocoa found, for example, antioxidant activities that protect red blood cells from damage or blocked the oxidation of DNA. But what flavanols do in a test tube may not take place in the human body. Some intervention studies that involve feeding cocoa or cocoa flavanols to people have shown that cocoa, and in particular the flavanols of cocoa, have effects that could benefit cardiovascular health. What studies show The flavanols present in cocoa indeed enter the blood stream after ingestion, a necessary first step if they are to have an effect. It has also been found that individuals who eat 75 grams of dark chocolate or chocolate enriched with cocoa polyphenols daily for 3 weeks show about a 12% increase in "good" (HDL) cholesterol, while those eating white chocolate (which has no cocoa polyphenols) show a 3% decrease in HDL. One human study on blood vessel dysfunction showed that blood flow increases significantly due to dilation of an artery when individuals are fed a cocoa drink enriched with cocoa flavanols. The effect peaks 2 hours after drinking and returns to baseline after 4 hours. Another human study on healthy individuals examined the difference between eating 100 grams of commercially available dark chocolate bars containing polyphenols and white chocolate bars without polyphenols, both with the same energy content. Participants ate one dark chocolate bar per day for 14 days. Blood pressure and insulin sensitivity were measured at the beginning and the end of the test period. Participants then repeated the test with white chocolate bars. The study shows that the dark chocolate decreased systolic blood pressure between 4.1 and 11.9 mm Hg and significantly improved insulin sensitivity. But white chocolate had no effect on either parameter. Similar studies in which a smaller amount (46 grams instead of 100 grams) of dark chocolate were consumed daily showed that this amount did not result in lowered blood pressure. The studies mentioned were short term and employed small numbers of individuals. The first large epidemiological study was reported recently and is described below: Recent update on cocoa benefits A study in the Netherlands examined the protective effects of chocolate in 470 elderly men over 15 years. At the start of the study, none of these men had a history of CVD, cancer, or high blood pressure. They were examined for various health parameters in 1985, 1990, and 1995 and were also interviewed on the composition of their diet. Researchers prepared a list of 24 cocoa-containing foods (drinks, puddings, nutritional supplements, etc.) and calculated the amount of cocoa consumed each day by the participants based on the estimated cocoa contents in the foods. The men were divided into 3 groups depending on the amount of chocolate they consumed daily: non-consumption, lower, and higher consumption. Results show that in 1985, about one-third of the men did not eat cocoa. The lower consumption group took an average 0.92 g/d of cocoa. The higher consumption group ate 4.18 g/d of cocoa, which is the equivalent of 10 g/d of dark chocolate. Cocoa consumers were more likely to eat candies, cookies, nuts and seeds, and drink alcohol. It also seems that the more cocoa they ate, the less meat and coffee they consumed. The study shows that a higher intake of cocoa is associated with lower systolic and diastolic blood pressure. Those with the highest cocoa consumption (> 2.25 g/d) were an average 3.7 mm Hg lower in their blood pressure than those who ate less cocoa (< 0.05g/d). Statistics on mortality and cause of death of this group of men were also examined. Between 1985 and 2000, 314 (66.8%) of the men had died, with CVD accounting for 152 deaths. Analysis of data indicates that those with the highest cocoa intake had the lowest number of deaths from CVD. Men in the high consumption group were half as likely to die from CVD as the others. This reduced risk was not associated with a higher consumption of nuts, seeds, or cookies and was independent of other factors such as weight, smoking, physical activity levels, calorie intake, and alcohol consumption. Furthermore, the higher consumption group was also less likely to die of other causes. Researchers suggest that long-term daily intake of a small amount of cocoa equivalent to only 10 g/d of dark chocolate lowers blood pressure and reduces the risk of death from heart disease. Continued study of cocoa and its flavonoids as significant protectors of cardiovascular health is warranted. Not all chocolates are created equal Dark chocolate usually contains more antioxidant flavanols than milk chocolate.White chocolate usually has very little or no flavanoids. The amount of flavonoids in cocoa products depends on the type of cocoa bean, the processing of the beans, and the processing of the cocoa for use in specific products. In some cases, as much as 90% of the original flavanol content may be lost during processing. An analysis shows that 40 grams of a milk chocolate contains 395 milligrams of flavonoids, while the same amount of dark chocolate contains 951 milligrams. As for hot cocoa drinks, 240 milliliters contains about 45 milligrams of flavonoids. |
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