How alcohol affects your Body and your Health

Alcohol is metabolised extremely quickly by your body.  Unlike foods, which require time for digestion, alcohol needs no digestion and so is more quickly absorbed and metabolised than other nutrients. About 20% is absorbed directly across the walls of an empty stomach and can reach the brain within one minute.

Once alcohol reaches the stomach, the enzyme “alcohol dehydrogenase” begins to break it down, reducing the amount of alcohol entering the blood by approximately 20%.  Women produce less of this enzyme, which partially explains why women are more quickly affected by alcohol than men. About 10% of the alcohol is expelled in the breath and urine.

Alcohol is rapidly absorbed in the upper portion of the small intestine. The alcohol-laden blood then travels to the liver affecting nearly every liver cell.  The liver cells are the only cells in your body that can produce enough of the enzyme alcohol dehydrogenase to metabolise alcohol, at the rate of about ½ ounce of ethanol per hour.  That is approximately one drink, depending on a person’s body size, food intake, etc. If more alcohol arrives in the liver than the enzymes can process, the excess alcohol travels to all parts of the body, circulating until the liver enzymes are finally able to process it.

Although alcohol affects every organ in your body, it’s most dramatic impact is upon the liver.  The liver cells normally prefer to use fatty acids as fuel, excess fatty acids being sent to other body tissues in the form of triglycerides.  However, when alcohol is present, the liver cells are forced to first metabolize the alcohol, letting the fatty acids accumulate, sometimes in huge amounts.  Alcohol metabolism permanently changes liver cell structure, which impairs the liver’s ability to metabolize fats.  This is why heavy drinkers tend to develop fatty livers.

The breakdown of alcohol by the liver requires high levels of the B vitamin niacin, which can lead to other vital body processes being deprived. In turn, this can lead to an acid state in the body and fat beginning to clog the liver. An accumulation of fat in the liver can be observed after only a single night of heavy drinking.

If you keep to the recommended guidelines and drink slowly through the evening, your liver copes reasonably well. However, heavy drinking overtaxes the liver with serious consequences.  A liver clogged with fat causes liver cells to become less efficient at performing their necessary tasks, which in turn affects your overall health.  A fatty liver is the first stage of liver deterioration in heavy drinkers, and interferes with the distribution of oxygen and nutrients to the liver’s cells.  If the condition persists long enough, the liver cells will die, forming fibrous scar tissue (the second stage of liver deterioration, or fibrosis).  Some liver cells can regenerate with good nutrition and abstinence, however in the last stage of deterioration, or cirrhosis, the damage to the liver cells is the least reversible.

Rates of liver disease are falling in the rest of Europe, but are rising in the UK.  Liver disease has traditionally affected drinkers in middle age, but now sufferers are getting younger. Up to one in three of the adult population is drinking enough alcohol to create a risk of developing alcohol-related liver disease.

If you are a moderate drinker, alcohol may actually increase your appetite, causing you to eat more than you really need and therefore gain weight.  Heavy, persistent alcohol consumption appears to have the opposite effect.  Alcohol causes euphoria, which depresses the appetite, so that heavy drinkers tend to eat poorly and become malnourished.

Alcohol is very rich in energy, at 7 calories per gram, but these are “empty calories” like sugar and fat, containing no nutrients that actually nourish the body.  The more heavily you drink, the less likely it is that you will eat enough food to obtain adequate nutrients.  Chronic alcohol abuse also interferes with the body’s metabolism of nutrients, leading to damage of the liver, digestive system, and nearly every bodily organ.

The short term health risks of alcohol include:

  • Anxiety
  • Depression
  • Skin problems
  • Sexual difficulties such as impotence
  • Impaired judgement leading to accidents and injuries
  • Slowed breathing and heartbeat
  • Loss of consciousness
  • Suffocation through choking on your own vomit (aspiration)
  • Potentially fatal poisoning

Regularly drinking more than the recommended number of units over a long period can lead to complications like:

  • Certain types of cancer, especially breast cancer
  • Memory loss, brain damage, stroke or dementia
  • Increased risk of heart disease and stroke
  • Liver disease, such as cirrhosis and liver cancer
  • Stomach damage
  • Potentially fatal alcohol poisoning
  • Damage to an unborn child
  • Male and female infertility
  • Increased risk of miscarriage
  • Osteoporosis
  • Pancreatitis
  • Stomach ulcers
  • Heart disease
  • Raised blood pressure
  • Obesity

Drinking alcohol can increase your risk of:

  • Mouth cancer
  • Pharyngeal cancer (upper throat)
  • Oesophageal cancer (food pipe)
  • Laryngeal cancer (voice box)
  • Breast cancer
  • Bowel cancer
  • Liver cancer

Every year, alcohol causes about 6% of cancer deaths in the UK, killing over 9,000 people.

Along with smoking, alcohol causes the vast majority of mouth and food pipe cancers. In the last decade, mouth cancer has become much more common and this may be because of higher levels of drinking.
Alcohol is second only to smoking as a risk factor for oral and digestive tract cancers.

This may be because alcohol breaks down into a substance called acetaldehyde, which can bind to proteins in the mouth. This can trigger an inflammatory response from the body, the most severe of which is the development of cancerous cells.

Most people who suffer from health problems because of their drinking are not alcoholics, but rather are those who drink heavily over a number of years. Many suffer few immediate consequences of their drinking, but cumulatively it takes its toll. 6,000 deaths from coronary heart disease in men each year are directly due to alcohol. And 400 of the 1,700 deaths from mouth cancer per year are linked to heavy drinking – that’s nearly one in four.

Because of the effects of alcohol on the brain, it is frequently associated with mental health problems such as depression, anxiety, self-harm and also suicide. In extreme cases (defined as drinking more than 30 units per day for several weeks) it can occasionally cause ‘psychosis’, a severe mental illness where hallucinations and delusions of persecution develop. Psychotic symptoms can also occur when very heavy drinkers suddenly stop drinking and develop a condition known as ‘delirium tremens’.

Heavy drinkers who drink daily, can experience withdrawal symptoms such as nervousness, tremors, palpitations, severe anxiety, and even phobias, such as a fear of going out.

Alcohol abuse over the long term has been shown in many brain imaging studies to actually, physically shrink the region of the brain that commands learning and memory. The shrinkage is more extensive in the cortex of the frontal lobe, which is known to be the center of higher intellectual functions, and of course this shrinkage will increase with continued alcohol use and age. Short-term memory loss is usually the first noticeable sign of alcohol related damage.

Progressive brain shrinkage was shown in a study that conducted periodic imaging in alcoholics over a five year period. The amount of brain shrinkage was directly related to the amount of alcohol consumed, but there was no question that the shrinkage far exceeded anything in the normal range.

Until around age 18 -19 the human brain is still in the process of development and may be more susceptible to damage than the adult brain. In adolescents who regularly drink alcohol, parts of the brain which are important in planning and emotional control have been found to be smaller than expected.

If you have been prescribed antidepressants, sedatives, analgesics or drugs for epilepsy you should avoid alcohol.

The health effects of alcohol are summarised in this table.

Arthritis Increases risk of gouty arthritis
Cancer Increases the risk of cancer in the liver, pancreas, rectum, breast, mouth, pharynx, larynx and oesophagus
Foetal Alcohol Syndrome Causes physical and behavioral abnormalities in the foetus
Heart Disease Raises blood pressure, blood lipids and the risk of stroke and heart disease in heavy drinkers.  Heart disease is generally lower in light to moderate drinkers.
Hyperglycermia Raises blood glucose
Hypoglycemia Lowers blood glucose, especially for people with diabetes
Kidney Disease Enlarges the kidneys, alters hormone functions, and increases the risk of kidney failure
Liver Disease Causes fatty liver, alcoholic hepatitis and cirrhosis
Malnutrition Increases the risk of protein-energy malnutrition, low intakes of protein, calcium, iron, vitamin A, vitamin C, thiamine, vitamin B6 and riboflavin, and impaired absorption of calcium, phosphorus, vitamin D and zinc.
Nervous Disorders Causes neuropathy and dementia; impairs balance and memory
Obesity Increases energy & calorific intake
Psychological disturbances Causes depression, anxiety and insomnia
Infertility In men, it damages the sperm and in women compromises health of the egg.


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