Article By: Harvey Finkel, MD
Not quite the solution to the french paradox. Just before Christmas 2OO1, the research group led by Roger Corder, PhD, at the William Harvey Research Institute in London, stimulated a flurry of excitement by publishing a brief communication in nature. proposing an explanation of the French paradox and of the mechanism by which red wine reduces the risk of coronary heart disease, the major killer and disabler of the developed world.
Calling endothelin-1, a peptide (protein building block) produced in blood vessels, "crucial in the development of coronary atherosclerosis," the Corder group found that a component of red wine suppressed the elaboration of endothelin-1. Endothelin-1 is a powerful constrictor of blood vessels, thereby bad for their health. The prudent took note with interest, but hedged their bets. Corder, who qualified as a pharmacist in 1978, has pursued a career in research. He is now professor of experimental therapeutics. He and his colleagues published another brief communication in nature in November, 2OO6, in which the previously unknown inhibitor of endothelin-1, and therefore of coronary and other blood-vessel atherosclerosis, is identified as a group of polyphenols, procyanidins, mainly derived from grape seeds. They are also found in chocolate, apples, cranberries, and some other fruits, nuts and spices. They are almost absent from grape juice, except Concord. Pomegranates contain a different, but still beneficial, polyphenol.
Corder believes that procyanidins (which are not antioxidants) are the prime healthful components of wine, chiefly functioning by counteracting the adverse effects of endothelin-1. As supporting evidence, he cites the relatively high proportion of people surviving to advanced age in locales producing wines containing abundant procyanidins: parts of southwestern France, Sardinia, Crete, and the former Soviet Republic of Georgia. In his new book, The Red Wine Diet (Avery, 2OO7), he seems to disdain the widely accepted contributions to health of the antioxidant polyphenols, including resveratrol, and of alcohol, and scorns modern soft, fruity, "easy-to-drink" wines low in polyphenols, especially those low in procyanidins.
Some grape varieties are particular rich in procyanidins, for example, the tannat of southwestern France. (Maybe that's why I've always liked Madiran). Vineyard features cited as favoring high procyanidin concentration include high altitude, infertile soil, mature vines, avoidance of excess water, long, slow ripening, optimal sun and heat, cool nights, low yield, sea breeze, fog. In the winery, there should be long skin and seed contact during fermentation, and minimization of fining and filtering. Of course, much of this is simply a recipe for producing good wine. Man's manipulations can obliterate the effects of most of these. Corder has concluded that the traditional winemaking preserved in the areas of high longevity, including the just-cited factors, is responsible for the long survivals, by means of the abundance of procyanidins.
The work of Corder's group is intriguing, but controversial. Neither methods of investigation nor the inferences drawn can be said at this stage to stand up unsupported as established science. And we have to account for the effects of alcohol and of the antioxidant polyphenols, both demonstrated as multifaceted enhancers of health. Once we are more certain of the role of the procyanidins, we can hope to integrate their actions into our still incomplete understanding of the formation of and protection from atherosclerotic disease of the coronaries and other arteries, not only with reference to drinking.