For many of us, alcohol is an enjoyable backdrop to life: wine with dinner, beers with friends, a glass of bubbly to celebrate a special occasion, or nip of something heavier to unwind after a long day.
Drinking picture from Shutterstock
But alcohol is the fourth-largest cause of disease in Australia after excess weight, smoking and high blood pressure. So, how do you decide whether — or how much — to drink?
Unfortunately, the answer is far from simple and falls into the murky realm of "it depends". Let's consider what the science says about the positive and negative effects of alcohol.
Drinking alcohol increases your risk of accidents and injury. Only tobacco outranks alcohol as the leading preventable cause of drug-related death and hospitalisation in Australia.
Between 1992 and 2001, more than 31,000 deaths were attributed to risky or high-risk alcohol consumption. And between 1993-94 and 2000-01, half a million people were admitted to hospital for alcohol-related injuries.
The more you drink, the higher your risk of cancer — and this is a steep exponential curve. So, with each incremental increase in your drinking, there is a marked increase in your risk.
The World Health Organization's International Agency for Research on Cancer has concluded there is "sufficient evidence" that alcohol causes cancers of the oral cavity, pharynx, larynx, oesophagus, liver, colorectum and female breast.
Unfortunately there is no evidence of a safe threshold; as soon as you start drinking your risk of cancer increases. This includes a 12% increase in the risk of breast cancer with each additional unit of alcohol per day.
The evidence is mounting for a "J- or U-shaped" link between drinking alcohol and developing cardiovascular disease (heart disease, stroke and other blood vessel disease). This means light to moderate drinkers have a lower risk of cardiovascular disease compared with those who drink nothing and those who drink a lot.
Heart disease is the most common cause of death in Australia, which makes the evidence on light to moderate alcohol consumption more relevant than it otherwise might be.
Weighing up the risk
So, how do you weigh up alcohol's role in cancer, injury and other risks with its beneficial effects on heart disease?
This is where things get tricky. We need to consider the balance of risk and how it might apply to individual populations. What, for example, is my likelihood of first getting cancer, compared with my risk of liver disease, having an accident, being injured or developing cardiovascular disease? The answer will be different for everyone.
In younger men, accidents and injuries are leading causes of death and cardiovascular disease is relatively uncommon. Drinking, therefore, poses a greater threat to them overall than the benefits it might afford. So they really should limit their consumption, or, ideally, avoid alcohol altogether.
The same is true for younger and middle-aged women, whose risk of breast cancer is higher than their risk of cardiovascular disease.
However, the cardiovascular health benefits of drinking are likely to be more pronounced in older people, particularly those aged in their 60s or above. It is interesting to note that cardiovascular benefits don't seem to differ according to the type of alcohol — wine, beer or spirits.
A moderate tipple
So if you are an older adult, and in an industrialised country, the current evidence suggests the beneficial effects of light to moderate alcohol consumption on cardiovascular disease are likely to exceed your risk of cancer and other conditions increased by alcohol. This means a moderate tipple is likely to help in increasing your overall longevity.
But if cancer is the thing you are most concerned about, the "don't drink at all" message should apply to you. And if you have an alcohol dependency and an alcohol-related condition, it's clear that cutting out drinking is the path you should take.
These messages are a hard sell. In many other areas of health advice there is happy alignment between health organisations: obesity and smoking being obvious examples. But in the case of alcohol, what protects you against cancer is not necessarily best for your heart.
This means people have to negotiate this tricky path without clear signposts. It's no wonder some people find it all too hard. Here it's worth returning to the alcohol advice from the National Health and Medical Research Council on reducing the risk of disease:
- Don't drink more than two standard drinks a day
- Don't drink more than four standard drinks on one occasion
- Don't drink while pregnant or breastfeeding
- Don't drink if you are under 15. And if you're 15 to 17, delay your first drink for as long as possible.
This advice is population-based, so any individual risk has to be overlaid on top of it. But it is a good start point for guidance.
Finally, the question of how much alcohol would minimise the overall risk of dying prematurely is different to asking what role alcohol plays in the development of disease.
Most public health advice about alcohol, including that outlined above, recommends upper limits of alcohol consumption but does not actually encourage drinking. But the evidence, in fact, goes a bit further. Taking individual risks and priorities into account, it indicates that for people in industrialised countries who have reached a later stage in their life, drinking at least some alcohol (but not too much) is likely to minimise the overall risk of premature death.
Although it's difficult to make decisions about the health effects of alcohol, we can be heartened by the fact that we have large body of evidence to guide us.
Emily Banks is Scientific Director of the 45 and Up Study at Sax Institute. She has received funding from The National Health and Medical Research Council of Australia, the Cancer Council, the National Heart Foundation of Australia and the Australian Primary Care Research Institute.