What determines our drinking habits?

What is alcohol?

Beer, wine, spirits, cider, and the scores of other drinks fermented or distilled around the world, all contain ethanol. Ethanol, which belongs to a group of chemical substances called alcohols, is produced when yeast assists the fermentation of sugar to form ethanol and carbon dioxide.

How much ethanol is in alcoholic drinks?

The amount of ethanol produced is controlled either by the quantity of sugar added or by the ethanol level reaching 14 per cent by volume, after which the yeast cannot survive. The carbon dioxide produced forms the ‘head’ on a glass of beer and the bubbles in champagne.

The process of distillation – boiling off and concentrating the ethanol part of the beverage – was discovered in the Middle East in AD 800 by a man called  Jahir ibn Hayyan. Distillation allows more concentrated and potent alcoholic drinks to be produced.

What else is in alcoholic drinks?

Other constituents (sometimes called congeners) in alcoholic drinks contribute to the taste that we may enjoy, but can also cause headache and a hangover if we have drunk a lot. The amount of congener varies – drinks with a dark colour such as red wine or brandy contain more congeners, and so cause more of a hangover than pale drinks.

How does alcohol affect us?

Although other constituents give drinks their colour, taste and character, it is ethanol that causes a change in our brain. This change can, if the circumstances are right, lead us to feel merry and talkative, or relaxed and sleepy. It is ethanol that helps us let our hair down. Celebrating, marking special events and meeting up with friends have become occasions for drinking. The advertising and marketing of the drinks industry are designed to make sure that we continue to believe in the good things about alcohol. Ethanol also causes some of the unpleasant effects of being intoxicated – such as the slowing of our thinking and our reactions, irritability and the tendency to do things on the spur of the moment which may be regretted later.

What are common measurements of alcohol?

Units

Many people nowadays talk in terms of ‘units’ of alcohol, to measure the amount. A pub measure of spirits (25 millilitres) counts as one unit. A 275 ml bottle of an Alcopop contains one and a half units.

Amount of alcohol in blood

For the purposes of measuring alcohol concentration in blood, we use the amount of alcohol (in milligrams) found in 100 millilitres of blood. This is written as ‘mg per 100 ml blood’ or ‘mg%’.

How does alcohol affect us?

As a very rough guide, one unit of alcohol drunk on an empty stomach results in a peak alcohol level of 15 mg% in a man. This figure will be up to 30 per cent higher in a woman, for reasons that we explain later.

The present legal limit for driving is 80 mg%. At this level, the risk of having a road accident is more than doubled. In experiments, bus drivers with alcohol levels of only 50 mg% (below the legal limit) thought that they could drive through obstacles too narrow for their buses. Concentrations of 400 mg% could block the brain’s breathing control centre and be fatal, especially if sedative drugs have been taken as well.

Breath tests

In breath tests, the units used are micrograms (µg) per 100 ml of breath. The breathalyser measures the alcohol contained in each 100 ml of breath. The present legal limit for driving is 35 µg per 100 ml breath (0.35 mg per litre).

On average, the body removes alcohol from the blood at about 15 mg% per hour (that is, about one unit of alcohol is cleared per hour). This means that a person who drinks eight pints one night may still be over the legal limit driving to work the next day.

Are we drinking more than we used to?

Compared with 100 years ago, the British are probably drinking less. Gin and beer used to be cheap, and we were great importers of brandy and wine. In 1914 Lloyd George, the British Prime Minister, was worried about the effect of alcohol on the industrial effort needed for the war, so steps were taken to reduce sales. Consumption fell dramatically and remained low in the depression years between the wars. Consumption began to increase in 1950, however, as prosperity in Britain returned. Tax on alcoholic drinks had limited drinking, but consumption has increased since 1950, as the tax imposed became a smaller proportion of people’s wages. In real terms, alcohol became cheaper. From 1965 to 2000, the amount that each adult was drinking, on average, doubled.Today, drinking problems are increasing. The UK death rate for alcoholic liver disease more than doubled from 1990 to 2007.Young people in Britain have increased the amount that they drink in a session. Young Danes are the drinkers in Europe who most often drink to get drunk.

What affects individual drinking habits?

Genetics

Some people dislike the taste or the effect of alcohol. Others like the effect from the start. This reflects their personality and their genes.

As drinking problems run in families. This is partly because a child who grows up with one or both parents drinking heavily may learn to do the same.

However, there is also a genetic factor. If a child whose birth mother or father had a drinking problem is adopted or fostered, he or she is more likely to have a drink problem in adulthood than his or her adopted or fostered siblings.

Identical twins, who share an identical chemical blueprint, tend to drink in a similar way because differences between people’s liking for alcohol result partly from differences in body and brain chemistry. In pairs of twins where one has a drinking problem, the other twin is more likely to have a drinking problem if they are an identical pair (exactly the same genes) rather than a non-identical pair (the genes are only as alike as those of other brothers and sisters).There is a genetic factor involved not only in whether or not people enjoy the effects of alcohol, but also in whether or not alcohol causes problems or addiction.

Social factors

Our pattern of drinking tends to be similar to that of our friends. For many people their circle of friends develops in their teenage years and changes little. People like to drink for the sociability and humour that go with it, and because it helps them break their routine. Second to watching TV, going for a drink is Britain’s favourite leisure activity. A new job or getting married can alter an established pattern. Spouses can have an influence on their partners’ drinking. For instance, when two sisters who are identical twins stay unmarried, they are likely to go through adult life drinking in a similar pattern, whereas if one or both marry, their drinking patterns begin to differ. In their later years, most people drink less than they did when they were 18 to 25.

Case history: Janet

Moira and Janet are identical twins who have enjoyed a close relationship ever since they were born. After graduating from the same university they even lived together when they both got office jobs in the centre of London. Although they chose the same career it was at different companies. Janet’s manager was an extrovert and also a keen golfer who loved the club life. At first Janet was resentful when his bachelor lifestyle continued after they were married, but she joined in with him rather than try to change him. Janet had not liked alcohol as a teenager and Moira became distressed as her sister gradually extended her pattern of drinking to become someone who, it seemed to Moira, always had a drink in her hand.

Work patterns

A person’s job influences his or her drinking. Jobs with high exposure to alcohol include the building industry, the drinks trade, hotels and restaurants, and work that takes people away from home – such as the armed services and sales travelling.

Religious beliefs

Some faiths recommend strict moderation or even total abstinence and the faithful adhere to this. There are religious writings going back thousands of years about the problems that alcohol can cause. Some religions give a specific place to alcohol, such as wine in Jewish family ceremonies. Occasionally

members of strict communities such as Moslem societies may drink but risk disapproval. They may run into difficulties controlling their intake because they have not learned moderate drinking in their family. Those who practise a religion are able to meet friends and take part in social gatherings without alcohol. This is in contrast to most social occasions and even some sporting events in our society, which usually involve drinking.

Drinking ‘to cope’

Alcohol is our favourite drug. Occasionally people drink more because they feel that it helps them cope with a problem or blots it out. However, one problem can become two, as the individual gets into the vicious circle called dependence, and the drinking escalates (see page 63). Dependence on alcohol can be a major problem, because drinkers begin to be unable to control how much or how often they drink, and find it very difficult to change. We explain this later.

KEY POINTS

• How much we drink depends partly on the genes that we inherit from our parents

• Some occupations lead to heavy drinking

• Drinking to solve a problem can lead to two problems