The health effects of alcohol are arguably under-researched, given the prevalence of alcohol consumption. While government guidelines for alcohol consumption often have more to do with medical politics than science.
It may come as a surprise to learn that the World Heath Organisation estimates that in 1st world economies the impact of alcohol consumption on mortality is positive, i.e. alcohol saves slightly more than it kills. Yes, even taking into account alcohol car crashes. That said, alcohol tends to kill the young, and save the old, so on balance it lowers average life expectancy. However if you aren’t a teenage male, or just don’t drink drive, then alcohol is more likely to save than take your life.
Alcohol also causes considerable misery (violence, debt) as well as pleasure. It’s difficult to work out the balance sheet on this issue.
A wide variety of different studies (cross sectional, longitudinal, experimental) all point to a J shaped relationship between alcohol consumption and mortality/disease. Moderate drinking does you good, but heavy drinking does you bad.
However, wine is a bit special. Even controlling for socio-economic, gender, and other confounding factors, wine has a different, better, J shaped relationship. And the positive effect of alcohol on mortality comes mainly from reducing heart disease, wine also reduces cancer incidence.
Here is a particularly comprehensive study, based on 3 longitudinal epidemiological surveys (21,000 participants, of which 5,000 died during the followup years). Note the J shaped relationship for alcohol consumption and all causes of death (the blue bars), and compare this to the (orange) cancer statistic. For cancer any level of alcohol consumption is associated with greater risk, but this is not the case for wine, as the 2nd chart shows.
So wine consumption appears to prevent heart disease, but it also has some preventative effect on cancer death. Even the group of wine-drinkers who consumed more than 35 standard drinks per week had lower mortality than the non-drinkers.
There is evidence that this effect is due to something else in the wine as well as the alcohol. It may also be due to wine being more likely to be consumed with food. It may also be that wine drinkers eat a healthier diet – the attempts to control for this suggest that there is still a wine (above the alcohol) effect, however this area is under-researched. Certainly there is a body of evidence that fruit and vegetable consumption has a quite a strong protective effect on cancer, and it’s quite possible that wine drinkers eat better.
World Health Organisation 2004 Global Status Report on Alcohol, Geneva, Dept of Mental Health and Substance Abuse.
Grønbæk et al (2000) Type of Alcohol Consumed and Mortality from All Causes, Coronary Heart Disease, and Cancer, Annals of Internal Medicine, 133: 411-419. The pictures above come from an excellent summary provided here.