Polyphenols are a very large group of chemicals. Some polyphenols are present in just about all food plants. These are the bioflavonoids. Though they are not essential nutrients like vitamins, these chemicals seem to enhance health in humans, vitamins that didn’t make the first team, if you will, because they are not absolutely essential for life. Very little is known about why plants bother to produce them and solid information about the place of bioflavonoids in human nutrition has also been very slow in coming. The most definitive evidence to support the value of bioflavonoids dates from 1997 and was discovered by “serendipity” which means the investigators stumbled on the information by accident—without setting out to look for it.
The Kuna Indians of Panama have inhabited isolated islands off the Caribbean coast for at least several hundred years. These Indians were studied in 1997 to determine why they had very little high blood pressure even in old age. The investigators also studied an enclave of Kuna Indians in Panama City. Unlike the Kunas on the isolated islands, the group living in the city had the same increasing evidence of high blood pressure with aging as the general population; so the answer to the question depended on finding the crucial environmental difference present in their island environment that was not present in Panama City. A great deal of effort revealed a complicated answer. Cocoa trees were plentiful in the Caribbean islands and the typical Indian drank 6 cups of a beverage prepared from the cocoa beans daily throughout life. Those in Panama City couldn’t afford such a large amount of the beverage when ingredients were purchased from commercial sources. Furthermore, the traditional processing of the beans did not destroy the bioflavonoids that are present in enormous quantities in raw chocolate. Commercial processing destroys most of these bioflavonoids, apparently in an effort to get rid of the bitter taste. So dark, bitter chocolate may be better for you than the more benignly flavored varieties.
Quite a cadre of nutrition researchers have sprung up lately—all working to get a data base listing bioflavonoids present in foods and to try to find out which ones are important in explaining the benefits of bioflavonoids to human nutrition--benefits such as the lack of high blood pressure in the Kuna Indians while they were living on their native islands. Some of the results of this bioflavonoid research follow. Green tea and black tea start out as identical leaves of the same plant. The difference is in the processing. For green tea, the leaves are just dried. To make black tea, the leaves are processed by fermentation that destroys most of the bioflavonoids. We might have predicted this from the cocoa story above. The bioflavonoids in grapes are mostly near the skin, so red wine that is fermented with the skins on has more bioflavonoids than white wine where the grapes are pressed into juice before fermentation (no skins). Purple or red grape juice has the most bioflavonoids of any grape product. Good news for teetotalers! Formerly I told the public to eat a varied diet to be more likely to get any undiscovered vitamins. The fact that vitamin B12 was discovered soon after my graduation probably stimulated my imagination. Now I tell them about bioflavonoids and to eat plenty of fruits and vegetables.
You will hear much more about this topic in the future. Bioflavonoid amounts may even appear on food labeling. In the event this happens, I intend to learn more about this subject to help you interpret those labels. Stay tuned. Exciting discoveries are being made regarding bioflavonoids. I hope I live long enough to accommodate you in this regard.
John A. Frantz, M.D.
Chairman, Monroe City Council Board of Health
March 2, 2002