Discover what's in your favourite tipple, the health benefits and risks of alcohol and how much you should be drinking.

What is alcohol?

Alcohol is a drug which has the immediate effect of altering mood. Because drinking makes people feel relaxed, happy and even euphoric, you may find it surprising to learn that alcohol is in fact a depressant. As such, it switches off the part of the brain that controls judgement, leading to loss of inhibitions. As most people are aware, alcohol also affects physical coordination.

The more alcohol consumed, the greater the effect - speech becomes slurred, vision blurred, balance is lost and movements are clumsy. Apart from cases of extreme intoxication, however, these effects are short-term. The liver breaks down and eliminates alcohol from the body, taking about an hour to deal with one unit.

The benefits and risks

Alcohol consumed in moderation is thought to be beneficial in reducing the risk of coronary heart disease. Indeed, alcohol consumption in conjunction with high intakes of fruit and vegetables, may well explain the so-called 'French paradox'. The French diet is considered to be very high in fat, especially saturated fat, yet the death rate from coronary heart disease remains relatively low. It is thought this is at least partly due to people's consumption of red wine.

The key word, though, is moderation. In 1997, the World Health Organisation concluded that the reduced risk from coronary heart disease was found at the level of one drink consumed every second day.

Alcohol has been linked to a wide range of illnesses, such as the increased risk of mouth, pharyngeal and oesophageal cancers (this risk being greatly increased if combined with smoking). Furthermore, alcohol probably increases the risk of colorectal and breast cancer.

And the list doesn't stop there: high blood pressure, gastrointestinal complications, such as gastritis, ulcers, and liver disease, and the depletion of certain vitamins and minerals can all be caused by alcohol consumption. Excessive alcohol consumption can also have detrimental social and psychological consequences.

Recommended intake

Often these problems arise when intake is considered to be really quite high. Moderation and balance is the key. British recommendations are two to three units of alcohol per day for women and three to four units for men and it's a good idea to have 2-3 alcohol free days each week.

What's a unit?

One unit is considered to be 8g of alcohol. Often units are quoted as being one small glass of wine, half a pint of beer or one pub measure of spirits. However, the alcohol content of different products does vary. Some stronger beers and lagers may contain as many as 2.5 units of alcohol per half pint. The size of some drinks may also vary; home measures of spirits are usually more generous than pub measures, and many bars now serve large glasses of wine as standard. Cans of beer and lager often contain about three-quarters of a pint, rather than half, and so will contain 1.5 units - more if the product is high strength.

The nutritive value of alcohol

Alcohol is a high source of energy, providing seven calories per gram of alcohol. Therefore, if you're watching your waistline it might be an idea to cut down the amount you drink or alter the type of drink you choose.

Alcohol is often referred to as a source of 'empty calories', meaning it has no nutritive value other than providing energy. This isn't strictly true; some alcoholic drinks contain sugars and traces of vitamins and minerals, although not usually in amounts that make any significant contribution to the diet.

The energy provided by an alcoholic drink is dependent on the percentage of alcohol it contains. It is difficult to give the calorie (Kcal) content for an alcoholic drink in general, due to the variance in alcohol content, and this must be considered when looking at the following values.