The effects of plant flavonoids on mammalian cells have been of substantial recent interest, with attention focused on the implications of these agents for cardiovascular disease and for cancer . Some epidemiological studies designed toexamine a possible protective effect of flavonoids in cardiovascular disease have reported inverse associations [2–15]. Inconsistencies may be due to measurement error because foods that are flavanol-rich, such as grapes, red wine, or cocoa and chocolate shows remarkable variability in the flavonoid content, largely reflecting processing [16–18].
The Kuna Indians of Panama are known for their low blood pressure levels and little rise in blood pressure with age [19–21]. Our interest began with a search for protective genes, but the protection was environmental rather than genetic . As no environmental factor identified to date will reduce blood pressure levels to 110/70 mm Hg — the average found in the Kuna, even those over 65 years of age — identification of potential environmental factors was of considerable interest. We learned that Kuna still residing in their indigenous location in the San Blas islands drank cocoa, all locally grown, as their major source of fluid. The cocoa proved to be flavanol-rich . The flavonoids were shown to cause the activation of nitric oxide synthase in healthy volunteers and patients with atherosclerosis [23, 24].