The debate on whether moderate alcohol use in healthy adults is harmful or not is still ongoing. In recent years, numerous studies have been carried out on the matter, though the results have been mixed.

Nevertheless, we do know that drinking an excess amount of alcohol over a long period of time, and even on one occasion, can seriously impact various parts of the body.  

In this article you can find:

  • What is alcohol?
  • What parts of the body does alcohol affect?
  • What is an alcohol overdose?
  • Signs of alcohol dependency
  • Where to seek help

What is alcohol?

Alcohol is a colourless volatile flammable liquid. There are several different types of alcohol, however, ethyl alcohol (ethanol) is the only form of alcohol that can be safely used in beverages. Ethanol is produced by fermentation; a chemical process whereby yeasts act upon certain ingredients in the food, such as grains and fruits.

What parts of the body does alcohol effect?

  • Brain: Alcohol is classed as a type of depressant. A depressant refers to a class of drugs that lower neurotransmissions levels within the brain, thus depressing or reducing arousal or stimulation in various areas of the brain, which ultimately decreases mental sharpness. For example, after an individual consumes a certain amount of alcohol, they may begin to experience slurred speech, disorientation, distorted perceptions, and/or the inability to react quickly or think rationally. In the longer term, drinking too much alcohol can damage, shrink, or kill brain cells, in which can result in long-lasting or permanent changes to the brain. Some symptoms of alcohol related brain damage include poor memory, learning difficulties, balance and coordination problem, fluctuation in temperament or personality, attention, and concentration difficulties, as well as mental health issues, such as anxiety and/or depression.
  • Heart: Drinking an excess amount of alcohol over a long period of time, or even on one occasion, can cause damage the heart. This includes cardiomyopathy (stretching and drooping of the heart muscle which makes it harder for the heart to pump blood to other parts of the body), arrhythmias (irregular heartbeat), stroke, and high blood pressure.
  • Liver: It is the liver’s responsibility to break down and filter out harmful substances in the blood, including alcohol. The second you take a sip of alcohol; your body prioritises breaking it down over several other bodily functions. This is because the body doesn’t have a way to store alcohol like it does with carbohydrates and fats, so it must immediately send it to the liver, where it’s metabolized. However, the process of breaking down the alcohol within the liver can produce harmful substances, causing fat to build up within the liver. This build-up of fat can result in inflammation and an increase in scar tissue which can seriously impact your liver’s ability to function as it should.
  • Immune system: Consuming an excess amount of alcohol can weaken the immune system. Alcohol impairs immune cells, whose role is to fight against infection and disease. Thereby, when immune cells are not working as well, there in an increased risk of contracting infection or disease, as well as other complications. Moreover, alcohol can trigger inflammation in the gut and destroy beneficial microorganisms which help to maintain immune health.
  • Pancreas: The pancreas is the large gland located behind the stomach and next to your small intestine. Excess alcohol consumption can also cause the pancreas to produce toxic substances that could potentially lead to pancreatitis. Pancreatitis refers to the inflammation of the pancreas, as well as the swelling of the blood vessel within the pancreas.
  • Stomach: Alcohol can increase the amount of acid in stomach, which could potentially lead to gastritis, inflammation of the stomach lining. Symptoms of gastritis include stomach pain, heartburn, loss of appetite, nausea, and vomiting, however, some individuals do not experience any symptoms. If gastritis is left untreated it can lead to stomach ulcers which can potentially result in death. Other issues alcohol can cause within the stomach include reflux and oesphageal varices (enlarged veins that develop in the walls of the lower parts of the oesphagus that bleed).

What is an alcohol overdose?

The majority of individuals drink alcohol for the stimulant effect it offers. For example, in small doses, alcohol can increase your heart rate, impulsiveness, and aggression. But if an individual exceeds the amount that their body can handle, they will then begin to experience the depressant effect.

When there is too much alcohol in the bloodstream, parts of the brain that control essential life-support system like breathing, heart rate, and temperature control start to shut down. This is what is known as an alcohol overdose. More severe depressant effects can occur in this state, such as the inability to feel pain, toxicity from where the body begins to vomit up the alcohol to remove it from its system, and lastly, unconsciousness, coma, or death because of severe toxic overdose.

Signs of alcohol dependency

Signs of alcohol dependency can include:

  • Not being able to function without alcohol (feeling anxious, upset, irritable, or angry when alcohol is not available, and/or not being able to sleep)
  • Alcohol being an important, or the most important, part of life
  • Continuing to consume alcohol despite negative consequences for you or your loved ones
  • Difficulty in controlling the amount of alcohol you drink, the number of times you drink, or when you stop drinking
  • Not being able to plan how much you are going to drink
  • Craving alcohol or having withdrawal symptoms (shaking, seizures, sweating, and sickness)
  • Not seeming to be drunk after drinking a large quantity of alcohol
  • Drinking first thing in the morning
  • Drinking every day/evening
  • Drinking often

Where to seek help

It is possible to overcome alcohol dependency. While it is difficult, many people have done so, and continue to do so. The HSE Drugs & Alcohol Helpline is a confidential service that has both a freephone Helpline (1800459459) and an email support service ( This helpline provides support, information, guidance, and referral to anyone with a question or concern related to drug and alcohol use. The service is non-judgmental and offers space to talk about your situation, to explore some options and to consider your needs.


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