effects of alcohol

The Effects of Alcohol on the Body

New government guidelines on alcohol have been updated for the first time in 20 years

We all know that we shouldn’t drink too much alcohol because it can be bad for you. But have you ever wondered why? What are the effects of drinking alcohol on the human body?

The type of alcohol found in alcoholic drinks is called ethanol. Ethanol is a colourless, flammable liquid that occurs naturally as a metabolic by-product of yeast fermentation. When drunk, alcohol is absorbed rapidly into the bloodstream and is metabolised (broken down) by the liver. Unfortunately the liver can’t break down alcohol quickly and so levels of alcohol can rapidly build up in the bloodstream.

Effects of alcohol on the brain

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Alcohol can cross the blood brain barrier so it is able to act directly on the cells inside the brain; and because alcohol has a physiological effect on the body, it is classed as a drug. Alcohol intoxication interferes with the brains communication pathways leading to slurred speech, clumsiness, changes in behaviour and difficult in thinking properly. The drug also affects a part of the brain called the hippocampus which is responsible for memory, this can lead to significant memory loss. In addition to these effects, alcohol alters the chemistry of the brain causing severe dehydration. In some cases, alcohol poisoning can stop the part of the brain that controls heartbeat and breathing1,2.

Effects of alcohol on the liver

The liver is a vital bodily organ that processes and removes toxins, makes blood clotting substances, and produces bile. Excessive drinking puts enormous strain on the normal processes of the liver. Chronic alcohol abuse provides the liver with far more alcohol that it can break down safely. Alcohol is energy dense and excess fat from its breakdown is deposited in the liver and other organs. Damage at a cellular level is caused by the release of a number of dangerous metabolic by-products, produced when alcohol is broken down, such as acetaldehyde and free radicals3. These components induce the death of cells of the liver, and cause harm to other vital body organs – including the pancreas, heart and digestive system.

Chronic, over-drinking can cause fatty liver, hepatitis and cirrhosis (irreversible liver scarring). Alcohol damage can lead to liver failure which is usually fatal.

Alcohol and cancer


The toxicity of ethanol is thought to be the result of direct damage to DNA by its metabolites, acetaldehyde and acetic acid4. Regular drinking increases the risk of cancer of the throat, oesophagus and larynx. Drinking and smoking together further increases this risk, possibly because alcohol damage allows harmful chemicals from the tobacco into the cells of the mouth5.  Alcohol can also increase levels of oestrogen which increases the risk of breast cancer6.

New government guidelines

The newly issued guidelines on alcohol consumption promote drinking in moderation. The guidance suggests that men and women should not exceed 14 units of alcohol (6 pints of lager or 7 small glasses of wine), drunk moderately over three or four days, pregnant women should drink no alcohol at all and that some days should be alcohol-free. In order to avoid the ill effects of alcohol, you should aim to drink as little as possible.

Read the full government alcohol risk guidelines


  1. http://sciencenetlinks.com/student-teacher-sheets/alcohol-and-your-brain/
  2. http://pubs.niaaa.nih.gov/publications/aa63/aa63.htm
  3. http://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/hepatology/alcoholic-liver-disease/
  4. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3685494/
  5. http://www.cancer.org/cancer/cancercauses/dietandphysicalactivity/alcohol-use-and-cancer
  6. http://www.cancerresearchuk.org/about-cancer/causes-of-cancer/alcohol-and-cancer/how-alcohol-causes-cancer


About the author: 

Sonia Nicholas is a Biomedical Scientist and Freelance Clinical Science Writer & Editor. She has been working in the field of clinical science for fifteen years.

Sonia believes that everyone can improve their health by eating a clean diet – a claim that scientific research increasingly supports. Sonia also believes that healthy, clean eating is accessible to all and doesn’t have to be an expensive lifestyle choice.

All of the information on The Green Apple Club website is in line with current, recommended Government guidelines. All of the articles are evidence based and fully scientifically referenced.

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