Any book that puts wine at the centre of the diet can’t be all bad. It was enough to draw the Chateau Shanahan literary team beyond the me-too cover hype – the usual promises of eternal life, or something like it, if you follow this diet.
But as we read through the book we found not a panacea, but a discourse on nutrition enlightened by population studies and medical research down to the molecular level – and one family of molecules in particular.
On page 32 we meet this star molecule – procyanidin – or one version of it, anyway. Our arteries dilated just looking at tetra-epicatechin, a strapping chain of four epicatechin molecules.
But before we discuss the procyanidin family, we should meet Roger Corder, author of The Wine Diet.
The jacket tells us that he’s Professor of Experimental Therapeutics at the William Harvey Research Institute, London. It says ‘he has pursued research into cardiovascular function and the links between diabetes and heart disease for 25 years, with the aim of discovering new treatments for these ever-increasing health problems’.
Corder’s long trail to procyanidin begins with a recounting of the so-called French paradox. About 25 years ago, he writes, ‘French epidemiologists observed that the French had relatively low rates of coronary heart disease despite high consumption of saturated fat’.
Then in 1991 Dr Serge Renaud appeared on 60 Minutes and shook America with the idea that ‘regular wine drinking could account for the French paradox’. This, says Corder, ‘split experts into the camps of believers and non-believers’.
Scientists continued to study the protective effects, or not, of alcohol in general and of red and white wine.
Much of the research focused on the benefits of the polyphenols found in red wine – of which our hero, procyanidin, is but one form. These compounds are derived from grape skins and pips and, to a lesser extent, from oak storage vessels.
Further population studies tended to confirm a heart-protective effect from red-wine drinking. As scientist drilled down, they examined an apparent correlation between red-wine consumption and reduced platelet aggregation – a risk factor in blood clotting.
For others, the search shifted to the anti-oxidant properties of red-wine polyphenols. Could they prevent the oxidation of LDL-cholesterol (the bad one)? The belief was that as LDL-cholesterol (the bad one) accumulated under the endothelium (the non-stick coating inside blood vessels) it oxidised and could become a trigger for atherosclerosis (arterial blockage).
Clinical trials showed that, yes, red wine polyphenols did indeed suppress LDL oxidation – whether ingested as red wine, as white wine laced with red wine polyphenols or as an extract without alcohol.
Not surprisingly this and other similar studies, writes Corder, led people to attribute the ‘anti-atherosclerotic benefits of red wine to the antioxidant properties of its polyphenols’.
But as further trials with anti-oxidants showed little efficacy in reducing the incidence of heart attacks, scientists began ‘wondering whether they have any relevance’.
The headline anti-oxidant during this period was resveratrol, another member of red wine’s polyphenol family. Corder discusses the case for and against resveratrol but dismisses it, quoting fellow scientist George Soleas, writing in 1997, ‘resveratrol is a very minor player indeed, and may even more accurately be characterized as a spectator’.
Corder agreed with Soleas partly because the concentration of resveratrol used in clinical trials bore no relationship to the quite small quantities found in red wine.
Moving away from the anti-oxidant qualities of red-wine polyphenols, Corder sought to identify the ‘most important component of red wine for modifying vascular function and preventing atherosclerosis’.
His laboratory research showed that red wine suppressed synthesis of endothelin-1 – an agent known to narrow blood vessels, raise blood pressure and trigger ‘processes leading to atherosclerosis’.
Corder and his colleagues ultimately identified our friends, the procyanidin family, as the polyphenols contributing to blood-vessel health.
Corder’s subsequent research identified areas, most notably in Sardinia, Italy, and Madiran, France, where consumption of red wines with high procyanidin concentrations coincided with low rates of heart disease.
A great deal of The Wine Diet isn’t about wine all. Not even the procyanidin bit, as Corder details the dozens of common foods rich in these compounds – from apples to walnuts to chocolate.
And on wine itself, Corder has more caveats than Clayton Utz: only red wines contain procyanidins and their concentration varies enormously from wine to wine; the greatest benefit is to be had by drinking wine with meals, as this reduces peak blood alcohol level; that consumption must be moderate; and that for women regular wine consumption, even at low levels, increases the risk of breast cancer.
Perhaps of even greater interest than the mighty procyanidin molecule is Corder’s discussion of nutrition in general. The Chateau Shanahan team found this the most illuminating part of the book – a level headed discourse on how we might balance our energy intake amongst carbohydrate, fat and protein and a rundown on the nutrients we need, why we need them and what we’ll find them in.
As we said at the start, any book that prescribes wine in our diet can’t be all bad. And it gets better when we’re encouraged, as Corder does, to eat a wide range of fresh products.
The Wine Diet — Complete Nutrition and Lifestyle Plan, by Roger Corder. Published by Sphere, an imprint of the Little, Brown Group $29.99
Copyright © Chris Shanahan 2007