"Nitric oxide plays such an important role in the maintenance of healthy blood pressure and, in turn, cardiovascular health," said Norman Hollenberg, M.D., Ph.D., professor of medicine at Brigham and Women's Hospital and Harvard Medical School and lead investigator of the cocoa study. "If our research results continue to support a link between consumption of flavanol-rich cocoa and nitric oxide synthesis, there could be significant implications for public health."
Dr. Hollenberg's research began as an inquiry into the difference between the isolated, island-dwelling Kuna Amerinds in Central America, who had a low tendency toward developing age-related hypertension, and Kuna who had migrated to the mainland, who did develop hypertension with age. It was observed that the island-dwelling Kuna had significantly higher nitrite/nitrate excretion than those on the mainland, which suggests that the nitric oxide pathway may be involved. The team learned that the Kuna consume large quantities of cocoa, findings that are published in the most recent issue of the Journal of Food Composition and Analysis, and they pursued the idea that this flavanol-rich food may play a part. To test this hypothesis, they fed Boston volunteers cocoa with either a high amount or low amount of flavanols, each of which was made for this study by Mars, Incorporated*. In the Boston study, subjects who consumed the high-flavanol cocoa, but not the low-flavanol version, displayed a renal plasma flow response that was consistent with the hypothesis that the nitric oxide pathway may play a role. Research is currently underway that will conclusively determine whether or not modulation of nitric oxide synthesis is the responsible mechanism for these positive observations. The high-flavanol cocoa used in the study was comparable to that consumed by the Kuna.
The nitric oxide mechanism of action may be similar to the method of action in certain pharmaceuticals products, like nitroglycerin. Nitric oxide is produced in the lining of blood vessels. Its major functions include opening up the arteries to increase blood flow, maintain elasticity and prevent platelets from adhering to artery walls. These protective mechanisms are important for good cardiovascular health.
Researchers at the University of California, Davis, led by Dr. Carl Keen, have conducted numerous studies that suggest that consumption of certain flavanol-rich cocoa and chocolate may positively affect cardiovascular biomarkers. The latest research, which also was presented at the AAAS symposium for the first time, simultaneously compared low-dose aspirin and a flavanol-rich cocoa beverage and found reductions in platelet aggregation with both. The researchers hypothesize that the responsible mechanism for the favorable platelet effects may well be related to the nitric oxide mechanism suggested by the on-going research of Dr. Hollenberg at Harvard.
The symposium, titled "Dietary Flavonoids: Heart-Healthy Nutrients or an Excuse to Enjoy Wine and Chocolate?", was sponsored by Mars, Incorporated. In addition to the Hollenberg and Keen research, the symposium also featured the following presentations:
"Flavonoids: What They Are and Where You Can Find Them," a discussion about what types of foods are most likely to be rich in flavanols and the status of the USDA flavonoid food composition database that will aid health professionals in making sound dietary recommendations, Harold Schmitz, Ph.D., Mars, Incorporated;
"New Research on Flavonoids: Mechanistic Implications for Cardiovascular Health," a review of new research that shows how dietary flavonoids can affect other biological systems thought to be associated with cardiovascular health, Helmut Sies, M.D., Department of Physiological Chemistry, University of Düsseldorf; and
"Molecular Mechanisms of the Antioxidant Effects of In Vivo Metabolites of Flavan-3-ols from Chocolate," a look at the bioavailability of flavanols in chocolate and their cell-protective effects, particularly against oxidative stress, Catherine Rice-Evans, Ph.D., Antioxidant Research Group, King's College, London.
Mars, Incorporated has been making confectionery since 1911. As one of the world's leading food manufacturers, Mars, Incorporated has a strong commitment to nutrition and health research and produces a wide variety of quality cocoa-based foods, including "M&M's"® Chocolate Candies, and SNICKERS®, MILKY WAY® and DOVE® Chocolate Bars. For more information about the latest research on chocolate and health, please visit the Chocolate Information Center Web site at www.chocolateinfo.com.
References: 1. Hollenberg NK et al. Proximate mineral and procyanidin content of certain foods and beverages consumed by the Kuna Amerinds of Panama. Journal of Food Composition and Analysis 2001;14:553-63.
* Typical retail cocoa would be considered low-flavanol.