How alcohol affects health and how to use alcohol responsibly
Alcohol has been used for centuries at celebrations and social occasions. It is a drug that alters a person’s mental and physical state, reducing tension and anxiety, and facilitating social interaction, but it may also cause loss of control over behaviour. Although moderate alcohol consumption (see Safe alcohol limits) promotes a feeling of relaxation and has a beneficial effect on health, excessive use of alcohol over a long period can result in a wide range of serious physical, psychological, and social problems.
Excessive drinking severely reduces life expectancy and is a significant cause of preventable injury or death. In the UK in 2007, there were more than 8,700 deaths that were directly attributable to alcohol. In the same year, there were more than 9,600 drink-driving accidents, which caused over 14,800 casualties, including about 460 deaths (see Safety on the road).
When you drink alcohol, it is absorbed into the blood from the stomach and small intestine. It is carried to the liver, where it is broken down by enzymes to be used for energy or stored as fat. A small amount is eliminated unchanged in urine and in exhaled breath. Alcohol reaches its maximum concentration in the blood about 35–45 minutes after intake. The actual concentration depends on various factors, such as the weight of the individual and whether the alcohol has been drunk with food or on an empty stomach.
The rate at which alcohol is broken down (metabolized) in the liver also varies between individuals, and heavy drinkers can metabolize it more quickly. The average rate is about 1 unit per hour. On any occasion, your body cannot alter the rate at which it breaks down alcohol, so that the more you drink, the longer it will take for your blood alcohol concentration to return to normal. If you drink heavily at night, you may still be intoxicated the next morning.
Alcohol is a sedative, depressing the central nervous system. In particular, it affects the part of the brain that controls movement, impairing reaction times and coordination. Your inhibitions are suppressed, and, although you may feel more confident, your judgment may be impaired for several hours after drinking. Just one drink is enough to have this effect, making it dangerous to drive or operate machinery. Alcohol dilates blood vessels in the skin. Although this may make you feel warm, you are actually losing heat. Therefore, alcohol should not be given to anyone chilled from exposure to the cold.
Alcohol causes increased urine production, and you may feel dehydrated if you have several drinks in quick succession. Heavy drinking often leads to a hangover, with headache, nausea, dizziness, and a dry mouth. Hangovers are the result of adverse reactions to alcohol itself and to chemical additives, which are found particularly in dark-coloured drinks such as red wine and whisky. You can slow the absorption of alcohol by eating when you drink. Drinking very large quantities of alcohol may cause confusion and loss of memory, loss of consciousness, coma, or, in extreme cases, death.
Some Asian people have a gene that causes an immediate adverse reaction to alcohol. Affected people have reactions such as nausea and facial flushing.
Drinking around 1 unit of alcohol a day may protect against coronary heart disease in middle-aged and older people. However, when safe limits are exceeded, the risks outweigh the benefits. Since alcohol has a high calorie content, regular drinkers often put on weight (see Controlling your weight). Alcohol damages most body systems and is a major cause of liver disease (see Alcohol-related liver disease). In the brain, cells that control learning and memory may be damaged (see Wernicke–Korsakoff syndrome). Drinking more than the safe alcohol limit increases the risk of cardiovascular disorders such as dilated cardiomyopathy, stroke, and high blood pressure (see Hypertension). Excessive consumption of alcohol increases the risk of several kinds of cancer, especially cancer of the nasopharynx, cancer of the larynx, mouth cancer, and cancer of the oesophagus. If you also smoke, the cancer risk is even greater. Drinking too much alcohol also reduces fertility.
Excessive drinking on a regular basis can lead to alcohol dependence and is a major cause of social problems. Regular drinking can also damage relationships and lead to considerable stress to a drinker’s family and friends.
Drinking during pregnancy increases the risk of fetal alcohol syndrome, and also the risk of miscarriage. Babies affected by fetal alcohol syndrome are abnormally small, with small eyes and a small jaw; they may also suffer from heart defects (see Congenital heart disease) or a cleft lip and palate, may suckle poorly, sleep badly, and be irritable. Safe alcohol limits during pregnancy are not known exactly. To be safe, it is recommended that women who are pregnant or trying to conceive should ideally abstain from alcohol completely, especially during the first 3 months of pregnancy, or, if they do choose to drink, to drink only small amounts (see Safe alcohol limits).
For women who are breast-feeding, occasionally drinking small amounts of alcohol – 1 or 2 units once or twice a week – is not harmful to the baby. However, drinking more than this may reduce your milk supply and may also affect your baby’s digestion, sleeping, and development. If you do choose to drink, you should wait for a couple of hours before breast-feeding so that the alcohol has had time to clear from your bloodstream and will not be in your breast milk.
If you think you may be drinking too much, consult your doctor, who might ask you to keep a diary for several weeks to record each drink you have.
Some people drink to relieve stress or painful emotions. Stress-related consumption may lead to the development of a drinking problem. Warning signs include drinking more than you intended on any occasion, severe hangovers, and being involved in accidents or arguments after drinking.
To enjoy alcohol safely, limit your intake. At social events, eat first, alternate alcoholic and nonalcoholic drinks, and finish each drink before refilling so that you know how many units you have had. Never drive if you intend to drink; try to go with a designated driver who will not drink. If you have children, set a good example for them. In addition, discuss the effects of alcohol with them and reinforce the message of any alcohol awareness programmes run by their school. To relieve emotional problems, try approaches such as counselling.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.