Bon santé: is wine good for your health?

Bon santé is a typical French toast. Good health! … or is it? For well over 2000 years wine was regarded as having special medicinal and health related benefits, but with the advent of modern scientific medicine in the mid-1800s such unsubstantiated notions were dismissed. Re-interest in the topic was kindled about 30 years ago when studies emerged suggesting mild to moderate alcohol intake might be beneficial, particularly through a reduction in cardiovascular deaths.1−3 There have been many subsequent reports confirming these observations and establishing the concept of a U- or J-shaped mortality curve, in which light and moderate drinking results in a decreased death rate compared with non-imbibers, only to rise again with heavy drinking.4−6 Confounding factors seem extremely unlikely.7 The magnitude of the effect of light and moderate alcohol intake is very significant with various studies reporting a reduction in vascular deaths by one-third to half, not only as a result of coronary thrombosis, but also ischaemic stroke.8 Benefit is not restricted to primary prevention but is also likely in those with prior heart attack9 or pre-existing cerebro-vascular disease.10,11 The risk of haemorrhagic stroke, which is increased by heavy alcohol intake, does not seem to be an issue with more modest imbibing.12 Various mechanisms have been proposed for these results, including the demonstrated beneficial effects of alcohol on lipid profile,13 favourable changes in thrombolytic profile,13,14 and decreased platelet aggregation.15 Were all alcoholic drinks created equal? The answer is no according to groups who highlighted the French paradox; that is, the mortality from cardiovascular disease is low in France in spite of high intake of saturated fats. It has been proposed that wine has special beneficial effects which explain this conundrum.16−18 There have been several studies published suggesting wine has beneficial effects on health not shared by other alcoholic beverages.19 Grønbaek et al.20 prospectively analysed outcome in over 13 000 adults after 10−12 years and compared non-drinking with various levels of drinking up to 3−5 drinks a day. With increasing intake, wine was associated with a steady fall in mortality, beer had no effect and spirits, at this upper level of consumption, was associated with an increased death rate. They suggested that the descending part of the U-shaped curved could be explained by the effect of drinking wine and the ascending limb might be a result of heavy spirit intake. Wine is an imperfectly understood complex soup of constituents, unlike some spirits, which consist of mostly ethanol. Attempts to explain the possible additional beneficial effects of wine have focused almost exclusively on its phenolics. These consist of a bewildering array of molecules with different side groups attached to phenolic rings. Many of these compounds tend to form polymers, some of which are very large. Grape juice, de-alcoholised wine and wine phenolics have effects on lipids, platelets and thrombus formation that are similar to those reported with alcohol.21−23 Such phenolics are powerful antioxidants and it has been proposed they also have a general effect in lessening cell damage and protecting against DNA fragmentation and cell death.24,25 The concept that phenolics underlie the purported health benefits in wine is largely speculative, but has led to the concept that red wine is better than white. Red certainly contains more phenolics than white; indeed the red colour is a result of such compounds. None-the-less, white wines also have significant phenolic content. In addition, many red wine phenolics are highly polymerised and as a result are relatively poorly absorbed.26,27 In this regard it is interesting to note the paper of Whelan et al. (in this issue of the Internal Medicine Journal) shows improved endothelial function after both red and white wine, which does not seem to be alcohol mediated and was unassociated with an increase in phenolics, as assessed colourimetrically, suggesting the effect was caused by colourless phenolic compounds or non-phenolics.28 The physiological actions of the extensive non-phenolic content of wine are virtually unexplored. There is no convincing epidemiological evidence that red wine is more cardio-protective than white and that which is available would be in keeping with both being equally effective.29 Several other non-cardiovascular benefits have been reported with mild−moderate consumption of alcoholic beverages, particularly wine. These include a reduced incidence of dementia,30−33 fewer white matter abnormalities on magnetic resonance imaging brain scan in the elderly,34 a lower incidence of type 2 diabetes ­mellitus,35−38 a low prevalence of the metabolic syn­drome,39 increased bone mineral density in elderly women,40 improved pulmonary function41 and reduced severity of asthma,42 and protection against Helicobacter pylori infection,43 to mention only a few. Alcohol increases the risk of colorectal and breast cancer and, paradoxically, one report suggests red wine may be a specific risk for the latter.44 Both of these cancers may be related to alcohol interfering with folate metabolism and the risk may be lessened by an adequate folate intake.45,46 Cancer of the oropharynx and oesophagus are increased by intake of beer and spirits, but probably not wine, which has been attributed to the anti-carcinogenic effect of wine phenolics.47 Spirits, but not wine and beer, have been associated with increased risk of prostate cancer,48 while alcoholic beverages in general have been associated with reduced incidence of non-Hodgkin lymphoma in older women.49 Although details may differ for specific neoplasms, an overall reduction in cancer by about 20%, compared with non-drinkers, was noted in a study of 34 000 middle aged Frenchmen, 77% of whom were wine drinkers.50 The evidence that mild to moderate alcohol consumption is associated with positive health benefits is robust and there is accumulating data suggesting that wine drinking is associated with a better overall outcome than consumption of beer and spirits. In an analysis of almost 130 000 adults followed for up to 20 years, drinking either red or white wine was associated with a lower risk of mortality than imbibing other alcoholic drinks.51 It sounds great − doesn’t it? There is, however, a catch. Wine drinkers tend to have greater IQ’s, more education, higher socio-economic status, better diets, lower mean body mass indices, more physical activity, fewer psychiatric symptoms and are less likely to smoke than beer and spirit drinkers.52−54 In addition, at least in the US, beer accounts for a disproportionate share of hazardous drinking.55 While some of these factors have been considered in the epidemiological studies of drinking different alcoholic beverages, others have not. It therefore remains a possibility that the results of studies comparing the different types of beverages are con­founded. The paper of Whelan et al. in the current issue of the Internal Medicine Journal,28 adds to the body of theoretical data suggesting wine has physiological and possible health related properties beyond those of alcohol and other alcohol-related drinks. This, however, remains to be definitely established. Nonetheless, the current evidence suggests that while you await the definitive publication you can rest back and enjoy a glass, so long as it is in moderation. Bon santé!