Good news for chocolate lovers!
In a recent U.S. survey, people were asked what words they would use to describe chocolate. Not surprisingly, people used terms such as “awesome, calming, delectable, heavenly, intoxicating, irresistible, sexy and sinful.” Few would argue that chocolate is a food loved by many. What is more exciting for dietitians, however, is that chocolate is beginning to draw scientific attention for its potential health benefits.
Chocolate and cocoa powder are derived from beans that contain hefty quantities of phytochemicals called flavonoids. Numerous epidemiological studies have shown that populations consuming a diet rich in flavonoids (including foods such as red wine, tea and certain fruits and vegetables) have lower rates of heart disease and stroke. What appears particularly significant about chocolate, however, is that it contains large amounts of a type of flavonoid called procyanidins (apples are also rich in these compounds). Both tea and red wine are made up mostly of flavonoids called catechins. Procyanidins are of a larger molecular size (several flavonoid units Joined together) and in preliminary research they demonstrate the greatest promise in terms of benefits for the heart.
Chocolate for Your Heart?
Research to date suggests three mechanisms by which chocolate or cocoa flavonoids may benefit the heart:
1. Antioxidant Protection
In the “ORAC” test (considered the gold standard for measuring the antioxidant power of foods), a dark chocolate bar and a milk chocolate bar scored much higher than black tea, green tea or one half cup of blueberries. Preliminary research (test tube studies) suggests that chocolate or cocoa flavonoids may protect the heart by inhibiting the oxidation of LDL (oxidized LDL is much more likely to result in the formation of plaque on the artery wall). In a recent clinical study from the University of California at Davis, participants consumed one, two or three servings of M&M’s semisweet baking bits (one serving = 35 g). As the amount of chocolate consumed increased, there was an increase in chocolate flavonoids in the blood as well as a corresponding decrease in markers associated with lipid oxidation damage.
2. Reduced Platelet Activity
In another clinical study from the University of California at Davis, participants consumed a flavonoid-rich cocoa beverage, After two and six hours, there was a decrease in markers associated with platelet aggregation and adhesion (stickiness of the blood), Both platelet aggregation and adhesion are associated with a higher risk of plaque formation on the artery wall. In addition, there was a significant increase in the time it took for the blood to clot (this was described by researchers as an aspirin-like effect on the blood).
3. Relaxation of Blood Vessel Wall
Preliminary studies in isolated animal tissues also suggest that cocoa or chocolate flavonoids may protect the heart by relaxing the inner surface of blood vessel walls. Flavonoids in chocolate appear to exert this effect by increasing concentrations of nitric oxide. Vascular relaxation is an important measure of heart health.
Chocolate: Good, Better, Best
Chocolate: is there a better kind? Generally speaking, dark chocolate contains about twice as many flavonoids as milk chocolate. Having said that, the way in which chocolate or cocoa is processed is critical to its flavonoid content. Manufacturing processes, such as fermentation and roasting, can destroy many of the flavonoids present. Mars Inc. (a leader in flavonoid research) has developed a proprietary process to help preserve cocoa flavonoids during processing. Products such as M&Ms, Snickers and Mars bars now carry a “Cocoapro” logo to let consumers know these products have been processed to maximize the retention of naturally occurring cocoa flavonoids. As future research unfolds, we may ultimately see a day when there is a recommended daily intake for flavonoids in the diet.
What to tell clients?
While the research is exciting, it is premature to prescribe chocolate as a food to reduce the risk of heart disease. Larger and longer-term studies will further our understanding of chocolate’s potential health benefits. What we can say is that chocolate is a much more complex and interesting food than we may have thought. We can also say something we’ve always said: that in moderation chocolate fits as part of a healthy diet: In closing, let me leave you with this quote from Professor Norman Hollenberg, Harvard Medical School,
“Although the evidence is still incomplete, it is worthwhile and constructive to consider the fact that the evidence for a health benefit of cocoa and chocolate at least matches, and probably exceeds, the evidence favouring green tea and red wine.”
To all my fellow dietitians who enjoy a bit of chocolate (as I do) now and again, perhaps now you’ll enjoy it just that much more!
For more information, including research summaries and reference lists visit: www.chocolateinfo.com or www.cocoapro.com.
Liz Pearson, RD
Author of “When in doubt, eat broccoli! but leave some room for chocolate”
LizPearson @aol. com
Copyright Dietitians of Canada Spring 2001
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