There has been a fair amount of bleating in Decanter magazine recently about the UK government’s warning to middle-class and affluent drinkers – “no more than a glass a night”.
The thing to remember is that health warnings are not entirely about objective science, it is very difficult for them to be. Guidelines and warnings are usually written with the most vulnerable, and least educated, in mind. For example, there is some evidence that smoking reduces the symptoms of schizophrenia but no public health professional will ever publicize this; not just because smoking carries far too many other risks for schizophrenics, but rather because the communicators fear that some people might take out the message that smoking has some health benefits (smoking is good for you ? !!)
Health professionals hold similar fears for alcohol messages. So in spite of the established health benefits of moderate drinking, especially for older people, few if any guidelines go so far as actually encouraging non-drinkers to start drinking (yet there are no such qualms for recommendations about exercise).
My point is that you just have to expect health warnings and guidelines for alcohol to be a bit paternalistic. They will draw on scientific evidence, but they won’t present an objective summary of it. Public health messages are not scientists talking to scientists.
That said, sometimes health educators go too far. Look at what the American Heart Association’s website says about alcohol. The evidence that moderate alcohol consumption reduces risk of heart disease is very substantial, yet the first thing they say about alcohol is is: “Limit alcohol. Drinking too much alcohol can raise blood pressure and lead to heart failure or stroke.” It’s silly of them to give tautological warnings (too much of anything is bad, that’s what “too much” means). And, as it is reasonable to expect that the Heart Association website is only talking about alcohol’s effect on heart disease (that’s what they say they are writing about), then they are misrepresenting the scientific evidence. Compare their rabid stance with this article from Harvard School of Public Heath. Notice the relative risk of death chart – even subjects in the 6+ drinks per day had lower risk of death from heart attack than those who did not consume alcohol.
In summary, public health announcements shouldn’t be expected to fully represent scientific evidence, they are trying to affect mass behaviour and so have to give a simple, often simplistic, message. Unthinking consumption of health warnings can, in some cases, be bad for your health.