THURSDAY, 1 JUNE 2006
The long term effect of heavy drinking is serious and the NHS estimates it spends £164m a year treating alcohol-related conditions.2. Binge drinking is defined as drinking more than 10 units of alcohol in a single session for men and 7 units for women
One unit is equivalent to 8 g of ethanol, which is about half a pint of beer. The current recommendation for alcohol consumption in men and women is a maximum of 21 and 14 units per week respectively. Minimal effects may occur at a blood alcohol concentration (BAC) of about 45 mg per 100 ml and 10 times this can cause death.
3. Alcohol is absorbed mostly through the stomach and small intestine
When you have a drink, about 20% of the alcohol is absorbed directly through the upper gastrointestinal tract, mostly the stomach, and the rest through the small intestine. About 5% is excreted by the kidneys and 5% by the lungs as vapour, which is the basis of the breathalyser test.
4. Alcohol is mainly broken down in the liver by alcohol dehydrogenase
This enzyme converts ethanol to acetaldehyde, which in turn is broken down by aldehyde dehydrogenase to acetic acid (a component of vinegar).
5. Alcohol affects both higher and lower centres of the brain
Alcohol enhances the action of GABA, an inhibitory neurotransmitter, and disturbs the processing of sensory information, resulting in unconsciousness and amnesia. In the cerebral cortex, alcohol depresses the behavioural inhibitory centres, so you become more talkative, more self-confident, and less socially inhibited. It also slows down the processing of information from the five senses, and can inhibit thought processes. As alcohol affects the limbic system, you may experience excessive anger, aggressiveness, withdrawal, and memory loss. Finally, alcohol affects the cerebellum, leading to uncoordinated muscle movements and loss of balance.
6. Alcohol causes dehydration
Alcohol acts on the pituitary gland to reduce circulating levels of anti-diuretic hormone (ADH). When ADH levels drop, the collecting ducts of the kidneys do not reabsorb as much water, resulting in an increase in urine production (diuresis) and dehydration. In fact, the hangover headache is caused by water loss from the brain due to excessive alcohol consumption.
7. The human body can adapt to continued exposure to alcohol
The body’s increased tolerance to alcohol involves an elevated level of alcohol dehydrogenase and aldehyde dehydrogenase, as well as an augmented brain activity. As the body becomes more efficient at eliminating the high levels of alcohol in the blood, you need to drink more to experience the same effects as before. This can contribute to addiction. These adaptations are accompanied by behavioural changes.
8. Long-term heavy alcohol consumption can affect the liver, heart and brain
The most common form of disease associated with alcohol abuse is liver cirrhosis, which is the scarring of the liver associated with destruction of its normal architecture. Atrophy of grey and white matter in the brain and increased risk of stroke can also result. Alcohol is also thought to lower levels of aldosterone and increase levels of corticosterone in the blood vessels and increase the vasoconstrictor response to noradrenaline. This leads to high blood pressure, which further increases the chances of stroke and heart failure.
9. Moderate alcohol consumption is thought to be beneficial to health
The French are known to consume foods high in saturated fats and cholesterol, yet they have a low mortality rate from coronary heart disease. Several red wine components show promise for their possible cardioprotective effects, for example polyphenolic components such as bioflavonoids and proanthocyanidins. Components of grape skin, such as resveratrol and nitric oxide, are also important, as the latter has a relaxing effect on the endothelium of arteries.
Ryan Patel is a third year Natural Scitentist specialising in Pharmacology
Written by Ryan Patel
