Where does alcohol come from? What happens to it in our bodies? Where does it go? What effect does it have? Few of us give these questions a passing thought as we sip our wine, beer or spirits. As long as we enjoy the taste and it makes us feel good, the less we know, the better. Right?

That depends. If you're consuming more than six drinks a day, you probably should know what it's doing to your brain. Among other things, the areas affected are involved in reasoning and how thirsty you feel - alcoholics are thirstier than teetotallers for a reason!

Alcohol also causes cancer and heart disease, and it wreaks havoc on the liver. In fact, thousands of Australians die every year from cirrhosis and alcohol-related diseases.

The irony is, alcohol is legal, while other much less harmful drugs aren't.

Of course, not everyone who drinks has a drinking problem. But what of people who can't control their habit? Is their behaviour genetic or learned? And is a little bit of alcohol better for you than none at all? Still want a drink?

1. The fall of the Roman Empire has been blamed on the consumption of alcohol!

Wine at the time was fermented and stored in vessels made of lead, and an additive was put in the wine to enhance the flavour and stop fermentation. The additive had a very high lead content, and it is believed that most of the Roman nobility who drank wine suffered from lead poisoning, of which mental instability is a symptom.


2. Alcohol in low and moderate doses causes a dilation of blood vessels in the skin.

This is why drinkers sometimes have a flushed face and heavy drinkers a red nose.

As well as causing the skin to turn pink, alcohol also makes the skin feel warm, which is why one of its traditional uses has been to treat people who have been exposed to the cold. Brandy especially is supposed to warm the body.

The fact is, alcohol has the opposite effect. This dilation of vessels actually causes heat loss from the extremities, which makes you more vulnerable to the cold. The vessels constrict in the first place to conserve heat, a defence the alcohol undoes.


3. A single dose of alcohol, if large enough, can be lethal.

A blood alcohol level of about 300-400 mg per 100 ml will usually cause loss of consciousness. However, highly tolerant individuals may show only moderate drunkeness at 400 mg per 100 ml, the normal LD50.

Death by alcohol usually results from respiratory failure, because of alcohol's depressive effect on the respiratory centre. Alcohol, then, is a rather toxic substance with the lethal dose uncomfortably close to the usual social dose. Hence the expression "dead drunk".

Fortunately, alcohol has a built-in safety feature: we either vomit or pass out before we have a chance to kill ourselves. The trick is not to do the two things simultaneously, otherwise you risk doing the rock star thing of choking on your own vomit.


4. There are two broad categories of hangover.

One is really withdrawal. People who drink all the time build up a tolerance to alcohol. Symptoms occur when this amount is withdrawn. These are tremors, irritability, anxiety and heightened sensitivity to light, noise and pain. In severe cases, hallucinations, delirium and even convulsions may occur.

The other is the old fashioned hangover. Symptoms typically emerge when our BAL (Blood Alcohol Level) starts to drop. These intensify thereafter but have usually dissipated within 24 hours, provided we haven't had anything more to drink.

A number of mechanisms appear to be involved in hangover.

The "homeostatic rebound theory" is proposed to explain withdrawal and hangover. The body of an alcholic adapts to having a certain amount of alcohol present more or less all the time. Withdrawal is what happens when they're deprived of alcohol, which their body now needs to function "normally". Conversely, the person with a hangover is not used to alcohol in their system. This means that when they stop drinking and their body returns to normal, they experience unpleasant symptoms.

Hangover may also be due to the congeners in drinks. These are the additional chemicals found in alcoholic beverages which are usually produced during the fermentation and distillation processes.

Another culprit implicated in hangovers is acetaldehyde. Alcohol is converted to this chemical by the enzyme dehydrogenase in the first step of alcohol metabolism. The conversion rate of alcohol to acetaldehyde is determined by the amount and activity of dehyrogenase a person produces. If acetaldehyde is not converted quickly, the levels of this toxic substance may rise and persist for longer in some people's systems.

Finally, your state of health when you drink is quite important in predicting the severity of hangover.


5. While it's clear that heavy drinking is very unhealthy, there is also evidence that light alcohol consumption can decrease the probability of death from ischaemic (loss of blood supply) heart disease. But there's a catch.

It depends on how old you are. For people under 35, any benefits are negligible, mainly because at that age, there's no heart disease to prevent. Also this age group is involved in the vast majority of car accidents caused by alcohol.

For people over 35, it's less straightforward. In light drinkers, there is less heart disease than in non-drinkers. However, there's more cancer. But the reduction in heart disease is much greater than the increase in cancer, so there does appear to be a net benefit.

The amount of alcohol required to produce this benefit in healthy adults - less than one standard drink (10 grams of pure alcohol) a day for women and about one for men - is much less than the upper limits set by the NH&MRC. There are no further health benefits to be gained by drinking more than this amount.


6. Alcohol makes you sleepy, but it affects the kind of sleep you have.

By slowing the cortigal EEGs (the electrical activity of the cortex), alcohol suppresses REM or dreaming sleep so you sink into slow wave sleep instead. Often when the suppression of REM sleep ends (which usually coincides with diminished BAL), there is a "REM backlash", during which you spend more time than usual much later on in the night in dreaming sleep. This may expain why you feel irritable and a bit vague the next day.


7. Measuring Alcohol Levels in the Blood.

Alcohol in the blood circulates through the lungs and vaporises into the air, so it's possible to measure the alcohol level in the blood and the rest of the body by measuring the alcohol vapor in exhaled air. The device that performs this test is known as the Breathalyser.


8. Over 90% of all alcohol consumed moves from the blood to the liver where it's metabolised.

The remainder is either eliminated unchanged in breath, sweat, tears, urine and faeces, or metabolised in the stomach.

The latter may account for the different effects of drinking between men and women. Men show significant amounts of alcohol dehydrogenase in their stomach linings (remember, the conversion rate of alcohol to acetaldehyde is determined by the amount of dehydrogenase available), which may explain why women, after drinking the same amount of alcohol, and allowing for differences in size, have a higher BAL than men.


9. What is the most popular alcohol.

Wine is the most popular alcoholic beverage with drinkers followed by regular beer.


10. Alcohol related mortality.

Alcohol is second only to tobacco as the major cause of drug related mortality in Australia. The most common alcohol related cause of death is cancer.



Janet Bell


Geoffrey Burchfield


Geoff Wheeler


Kathy Graham

ABC Online
© 1997 Australian Broadcasting Corporation