How do I work out how much alcohol I am drinking?

Not many people drink neat alcohol, and so to help calculate how much alcohol there is in any particular drink most people talk about units of alcohol. This is the same sort of thing as calories in food.

1 unit of alcohol is 10 mls of pure alcohol:

Originally this was the same as:

• A small glass of wine
• Half pint of normal bitter
• A single measure of spirits(25ml)

However over the years the drinks industry have made drinks stronger:

Most lagers or ciders are now 5% alcohol by volume, and a pint is 3 units.

Pub glasses of wine are 175ml or 2.5 units, or even 250ml or 3.5 units.

Even measures of spirits have often been increased from 25ml to 35ml or 1.5 units.

You would think that the drinks industry would be heavily advertising this "added value" particularly as they have kept the prices the same and they spend over £265 million on advertising in the UK each year, but strangely they have kept it very quiet - often with just a tiny postcard sized notice next to the bar. One could almost think that they are trying to get people drunk.

The alcohol content of some normal drinks is as follows:

• Small bottle of lager or alcopop 1.5 unit
• Can of lager or cider 2.2 units
• Pint of 5% lager 3 units
• Pint of very strong (8%) lager or cider 5 units
• Bottle of wine 9 units
• Bottle of spirits 30 units

How much alcohol is safe to drink?

The issue of how much is safe to drink is complex because alcohol causes a wide variety of health problems in different ways, and may also be protective for heart disease. So for example if you wished your cancer risk to be as near zero as possible then the advice would be to drink no alcohol, on the other hand drinking up to the recommended limit may give some protection from heart disease.

For a healthy middle aged person the risks start to outweigh all the benefits at around 14-21 units / week for women and men respectively, the health risks start to really escalate above 20-30 units / week respectively, and at 35-50 units a week respectively the health risks become severe.

In addition there are other co-factors so for example obesity almost certainly increases the risk of both alcohol related cancer and liver disease. Whereas the individual 'safe limit' for a thin healthy man may be 21 units or indeed slightly more, there may be no completely safe limit for an obese man with diabetes, a woman who terrified about breast cancer or for the 20% of the UK population that have fatty liver disease. It is all a question of relative risk v the enjoyment that you may get from drinking alcohol - see the section on alcohol and cancer if you would like to know about these risks in more detail.

All heavy drinkers are increasing their health risk, but the actual absolute extent of this risk depends on both alcohol intake and on other factors.

The UK Department of Health's current advice on sensible drinking can be summarised as follows:

Men

The government advice is to be sure that alcohol will not harm your health you need to be drinking less than 21 units a week, this is just over 2 bottles of wine or 8-10 pints of beer or lager.

As liver doctors we start to become concerned at around 30 units / week, and become very concerned at 40-50 units / week. This may seem like a lot of booze, but it is only 4-5 bottles of wine each week and plenty of people in the UK drink this much much these days. Turn to the liver section for advice.

Women

Up to 14 units a week or one and a half bottles of wine the risks and benefits may balance in out some people - above this all the potential health benefits have disappeared, and the risk of high blood pressure, breast cancer and stroke increase.

Drinking more than 20-30 units a week may give you a fatty liver - and may cause more serious problems. Turn to the liver section for advice.

Regular v binge drinking

The government changed their advice on weekly units it to a daily measure because they were concerned that people would think it was OK to drink all the units in one go. In actual fact as far as the long term health risk are concerned, regular drinking is no better than binge drinking - it is the overall alcohol intake that counts. The benefits of alcohol on the heart do tend to disappear if you drink it all in one go.

These figures are all based on the modelling of an alcohol intake across a whole population. As far as serious liver disease is concerned the risks start at at around 3-4 bottles of wine a week, and are relatively small at this level. As alcohol intake increases then the risks increase correspondingly - see the liver section for details.

As liver doctors we are concerned about the daily drinking advice because daily drinking is pretty much guaranteed to cause tolerance where the amount you need to drink to get the same buzz gradually increases.

If you do have a drink most days then you may be storing up trouble for yourself.

Drink-free days

Try not to drink alcohol every day, if you are a moderately heavy drinker give yourself a rest for at least two to three days a week.

Some of the research that we are doing in Southampton is starting to suggest that this may be the most important thing of all.

If you try to cut out alcohol from Monday to Thursday and find it difficult then you probably have a degree of alcohol dependency, and this in itself is something that you should be thinking about.

Pregnant women

Many mothers prefer not to drink at all during pregnancy because alcohol passes straight into the bloodstream and travels to the baby. There is no evidence that an occasional glass of wine causes any harm to a pregnancy, but regular drinking can lead to a problem called fetal alcohol syndrome, and evidence is emerging that even occasional alcohol binges can cause problems as well.

If you are pregnant or trying to get pregnant then think carefully about whether you should be drinking alcohol.