What is alcohol?

What is alcohol?

Alcohol is a common term for ethanol, a compound produced when glucose is fermented by yeast. The alcohol content of a particular drink is controlled by the amount of yeast and length of fermentation.

Fruit is used to make wine and cider, while cereals such as barley and rye form the basis of beer and spirits.

Alcohol is a drug that has the immediate effect of altering mood. Drinking it makes people feel relaxed, happy and even euphoric, but in fact alcohol is a depressant. It switches off the part of the brain that controls judgement, leading to loss of inhibitions. Drinking even small amounts of alcohol can affect physical coordination.

The liver breaks down and eliminates alcohol from the body. It takes the liver about one hour to deal with one unit of alcohol (8g).

Benefits

Alcohol consumed in moderation is thought to help reduce the risk of 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 (CHD) remains relatively low.

A research study published in 1992 suggested that the low death rates from CHD could be due to the relatively high consumption of wine in France. A similar pattern of diet and alcohol consumption has also been found in other south European countries where heart disease rates are also lower compared with other parts of the world.

These observations prompted a long series of research studies analysing the relationship between wine and CHD.

It's still not entirely clear how alcohol reduces your risk of CHD, but it's now known a large proportion of the risk reduction is due to moderate alcohol intake raising 'good' cholesterol concentrations in the blood, so reducing the risk of blood clots.

Red wine, in particular, also contains flavonoids that act as antioxidants, which help to reduce the build up of atherosclerosis (when fat builds up on the inner walls of arteries). Red wine seems to help maintain the flexibility of the blood vessel walls.

Risks

Drinking too much alcohol will not only leave you with a hangover the next day, but binge drinking and/or drinking more than the recommended intake on a regular basis can also cause long-term damage to the body's internal organs.

Chronic alcohol use is one of the major causes of liver cirrhosis (irreversible scarring of the liver). This happens because healthy liver cells die and the dead cells are replaced by fibrous tissue.

The liver plays a central role in many essential body functions including the metabolism of carbohydrates, proteins and fats, detoxification and excretion of waste products from the body. Scarred tissue cannot function like healthy tissue so this condition can be life threatening if not treated early enough.

Stomach ulcers and gastrointestinal complications, as well as fertility problems, weight gain, and depletion of certain vitamins and minerals can all be caused by excessive alcohol consumption.

Binge drinking can also increase blood pressure, a risk factor for heart attacks. One study showed binge-drinking patterns in Northern Ireland at the weekends led to higher blood pressure levels, and a higher incidence of heart attacks on Mondays and Tuesdays. Blood pressure levels in French drinkers were constant throughout the week, reflecting their moderate drinking patterns.

A 2007 World Cancer Research Fund report showed alcohol increases the risk of cancers of the mouth, pharynx, larynx, oesophagus, colon (especially in men) and breast.

If you're worried about the negative effects of alcohol, either on yourself or on behalf of someone else, Alcohol Concern offers an excellent service.

Recommended intake

Moderation is the key. In the UK, the recommendation is no more than two to three units of alcohol a day for women and three to four units for men, with at least two or three alcohol-free days each week.

What's a unit?

One unit is considered to be 8g of alcohol, or equivalent to:

• Half a pint of standard strength (3.5% AVB) beer, cider or lager
• A pub measure of spirit
• Half a standard glass (175ml) of wine
• A pub measure of sherry, vermouth or liqueur

It's important to remember units differ according to the:

• size of your drink - pubs often serve wine in different-sized glasses, and home measures of spirits are often more generous than a pub measure
• varying alcohol content of different beers, wines and spirits

The size and strength of your drink determines how many units of alcohol you consume.

Calculating units

Establish the strength of the drink (% ABV) and amount of liquid in millilitres (one pint is 568ml; a standard glass of wine is 175ml).

Multiply the amount of drink in millilitres by the percentage ABV, and then divide by 1,000.

For example, 175ml wine at 13% ABV:
175 X 13/1000 = 2.3 units

To make matters easier, many manufacturers state how many units of alcohol each can or bottle contains.

Nutritional value of alcohol

Each gram of alcohol contains seven calories. If you're watching your waistline, cutting down on alcohol will help to reduce calorie intake. Alcohol can also weaken your willpower, tempting you to eat more than you planned.

Alcohol is often referred to as a source of 'empty calories', meaning it has no nutritional value other than providing energy. The energy provided by an alcoholic drink depends on the percentage of alcohol it contains, but also on the type of drink it is. For example, a creamy liqueur will have more calories than a clear liqueur. As a rough guide:

• A pint of continental lager is about 215 calories
• A measure of spirit contains around 55 calories, but this doesn't include calories from the mixer - try to choose low-calorie options
• A standard glass of dry white wine or red wine is about 115 calories, and sweet wine is about 165 calories
• A creamy liqueur contains around 163 calories per 50ml serving, while the same amount of sherry or port contains around 60 calories a glass