Healthnotes Newswire (November 8, 2001)—Eating chocolate or cocoa (from which chocolate is derived) causes certain changes in the blood that might reduce one's risk of developing heart disease, according to a report in this month's issue of the American Journal of Clinical Nutrition.¹ In this new study, 23 healthy volunteers were randomly assigned to consume a typical American diet or the same diet supplemented each day with 16 grams (approximately one-half ounce) of dark chocolate and 22 grams (approximately three-quarters of an ounce) of cocoa powder. After four weeks, each person was switched to the other diet, which they consumed for another four weeks.

Blood tests were performed at the end of each diet period. Compared with the typical American diet, the diet containing added cocoa and chocolate significantly improved two measures of heart disease risk: it increased total antioxidant capacity in the blood and reduced the rate at which low-density lipoproteins (LDL, or "bad" cholesterol) became oxidized. It is well known that oxidation of LDL cholesterol in the body can trigger the development of hardening of the arteries (atherosclerosis). Presumably, compounds that inhibit such oxidation would help prevent heart and blood vessel disease. Chocolate and cocoa contain certain flavonoids (procyanidins and catechins) that appear to function as antioxidants. The presence of these compounds could account for the increase in total antioxidant capacity and the inhibition of LDL oxidation that were observed in this study.

It should be noted that an improvement in cardiac risk factors does not automatically translate into a reduction in heart-disease risk. By analogy, even though taking estrogen reduces serum cholesterol levels, it does not reduce the risk of having a heart attack. In addition, the theoretical benefits of eating chocolate must be balanced with the potential risks. Most chocolate products are high in fat, sugar, and calories, and consuming excessive amounts of chocolate could promote obesity, which might actually increase the risk of heart disease. Chocolate contains a number of different chemicals that can affect the brain and nervous system. In addition to relatively large amounts of theobromine (a compound similar to caffeine), chocolate contains phenylethylamine (which has actions similar to those of amphetamines) and a recently discovered molecule called anandamide (which binds to the same site in the brain as does the active ingredient in marijuana).² The effects of these compounds on human health are not entirely clear; however, chocolate does appear to be a "mind-altering" food, with potentially negative implications for some people. In addition, chocolate can be addicting, as the many people who crave it will attest.

Nevertheless, the results of this new study suggest that, for some, consuming small amounts of chocolate is not harmful, and may actually be beneficial for the heart.