Page last updated: Tuesday, November 18, 2008
Polyphenols - much being learnt about the role and pathways of antioxidants in our bodies
‘Perhaps happily, it seems to be the combination of drinking moderately, preferably at meal times, in conjunction with a Mediterranean style diet that confers the most benefit rather than any one ingredient of wine or antioxidants generally’.

A fascinating wine and health congress took place in Graves, Bordeaux between the 20th and 22nd September, attended by the ‘pioneers’ of alcohol related research. Evidence showed the protective effect of wine on the cardiovascular system and total mortality. Attendees included Serge Renaud, Arthur Klatsky, R Curtis Ellison and Fulvio Ursini, as well as many younger researchers from all over the world.

Scientists from many countries met to discuss and analyse the latest findings regarding wine, and particularly its polyphenols, and the wider issues regarding moderate alcohol consumption, diet and health. There is no question that wine and especially red wine is a potent source of antioxidants, or that alcohol assists the solubility of these antioxidants. But what is still far from proved is whether our bodies absorb and assimilate these antioxidants in quantities high enough to have any biological effect. Increasingly, many of the polyphenols, and especially their metabolites, are being found to not only be absorbed but to have important biological effects in humans. Some well known antioxidants, such as resveratrol are less well absorbed than lesser known compounds such as gallic acid and procyanidins.

What was clear from data reported at the conference was that people who begin to consume a Mediterranean diet, especially when including the regular consumption of wine, showed a marked improvement in health. (Ellison analyses findings reported by Federico Leighton at the meeting later). Furthermore, the combination of such a diet with other lifestyle factors -- not smoking, staying slim, exercising regularly -- resulted in greater health benefits. But somewhat surprising was a report of a recent study at Harvard University showing that even among the “healthiest” men (non-smokers, lean, ate a Mediterranean diet, and exercised regularly) those who also drank moderately had their risk of a heart attack lowered, indicating an independent protective effect from alcohol.

Arthur Klatsky looked at the evidence over the last 100 years concerning alcohol and cardiovascular conditions. He was able to make the following statements:

Blood pressure increases at consumption levels above 30g a day, irrespective of beverage choice, further more high blood pressure carries risk, whatever your intake of alcohol is.

Problems he faces as a researcher in the Kaiser Permanente study, is the under reporting of consumption by a proportion of so called ‘moderate drinkers’, who they managed to isolate and study further, by analysing their liver enzyme activity and find they do show different health outcomes to genuine moderate drinkers – such as higher blood pressure.

There is also the issue of ‘The healthy user’, whereby many moderate drinkers are generally healthier than abstainers or heavy drinkers – i.e. they eat better, exercise more and are generally of a higher socio economic status.

Ex drinkers should be excluded from studies as ‘abstainers’ due to lower health status.

However, taking into account and adjusting for the above, more than 100 studies have reaffirmed the J shaped curve illustrating the cardio protective effect of moderate alcohol consumption in populations at greater risk of heart disease, i.e. men over 40 and post menopausal women, with a more U shaped association for elderly populations.

Drinking above moderate levels (30g a day) increases blood pressure, cardiomyopathy, risk of hemorrhagic stroke and heart rhythm disturbances, in line with sensible drinking guidelines from around the world.

Klatsky concluded ‘The amount of alcohol taken is a crucial consideration in all alcohol health relations. Defining a sensible limit is made difficult by inconsistency among studies in categorisation of alcohol intake, by differences in drinking habits and patterns and probably by under reporting of intake. Advice to concerned persons needs to take into account individual risk/benefit factor in drinkers or potential drinkers’.

Do polyphenols show extra protective effects for the heart?

Ludovic Drouet reported on his studies of polyphenols in mice and pigs and their effects on blood pressure, thrombosis and antherosclerosis. 30 former studies have suggested that polyphenols may reduce antherosclerosis or (thickening of the arteries). These investigators found that polyphenols had an anti – thrombotic affect (ie helped blood flow and reduced ‘stickiness of platelets), but did not reduce the build up of cholesterol on artery walls (lesions) or reduce serum lipids. Their experiments on pigs fed a diet of high fat (lard supplement) and red wine extract (without alcohol) saw no reduction in atherosclerosis after two years or improvement in ‘good’ HDL cholesterol or reduction in blood pressure. The authors conclude therefore that polyphenols may protect the heart via an anti thrombotic reaction, but do not reduce thickening of the arterial walls or lesions.

Why should wine protect against cardiovascular disease (CVD)?

Professor Bertelli from the Department of Human Morphology at the University of Milan, reviewed the biological basis of the beneficial effects of wine and CVD.

Professor Bertelli has spent 15 years studying resveratrol and other antioxidants and believes ‘we are just at the beginning’. Resveratrol is unique to wine and grapes but is badly absorbed – whether in wine or pill form. However, evidence of his research over the years concludes that:

1. phenol compounds in wine are bioavailable if consumption is regular (little and often)

2. These phenolic compounds may react with other similar compounds ingested with other foods.

3. Small daily doses allows polyphenols to accumulate in body tissues, affecting bioavailability, even in low doses

The importance of drinking at meal times

Fulvio Ursini from the University of Padua discussed the fact that for anti oxidants to be useful, they need to be taken with foods which contain fats which oxidise – ie if you drink with your meal it helps break damaging fats and oxidants, which contribute to the accumulation of bad LDL cholesterol. Ursini concluded ‘Although it is unlikely the sole mechanism of LDL production, the intake of foods prone to oxidation seems relevant, accounting for the known harmful effect of some dietary habits and for the protective effect of fruit, vegetables and wine taken with food’.

Fascinating human diet change experiment in Chile

Professor Federico Leighton reported on the results of an experiment in changing the diet of Chilean Miners, who had historically needed 8000 calories a day to maintain their highly physical work, but now due to mechanisation were ‘sedantry’, eating badly and well beyond their dietary needs. The intervention was through an improvement of the food offered in their canteen, combined with education, part of a ‘food and work’ initiative. Their health was measured in terms of predictors for ‘The metabolic syndrome’ (MS) which is a predictor of heart disease, late-onset diabetes and stroke – it includes suffering from symptoms including elevated blood pressure, high cholesterol and a high abdominal fat level - 25% of the 150 workers had MS. Twelve months later after the ‘Mediterraneanisation’ of their diet, the workers had slimmed, had a redistribution of fat away from their abdomens, had lower blood pressure and better antioxidant activity (reduced oxidative stress) – their risk of MS fell by 32%. It would be interesting to see if the workers stick to a healthier diet long term; the signs were good in that they asked for their wives and families to be taught about a ‘heart healthy lifestyle’. For further details visit www.pam-chile.cl

Professor R. Curtis Ellison summarises three papers from the conference on page 15. For further information and abstracts of the conference, pleae contact organiser Professor Pierre Louis Teissedre via: p.teissedre@u-bordeaux2.fr

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