Alcohol Consumption and Disease Complications

alcohol consumption

Alcoholic beverages like beers, wines and spirits contain ethanol, a strong psychoactive agent which can acutely affect our perception, mood, consciousness, cognition, or behaviour. It also has multiple implications on our body systems, posing longer-term health risks. Alcohol consumption leads to 3 million deaths each year and is the leading risk factor for premature mortality and disability for those aged 15 to 49. 

What happens when you drink alcohol? 

Absorption of alcohol

A small amount is first directly absorbed by the mucosal lining of the mouth and tongue. Once alcohol reaches the gut, it is absorbed into the blood stream via the tissue linings of the stomach (~20%) and then the small intestine (~80%). If you eat before drinking, the food in the stomach will dilute alcohol and delay passage into the small intestine, slowing down absorption.

Metabolism and Elimination of alcohol

The liver is the main organ responsible for detoxification and >90% of alcohol is metabolised or broken down in the liver. The rest exits the body via urine, sweat and breathing. The liver can only process a certain amount of alcohol at a time. When someone has had too much to drink, the alcohol left unprocessed by the liver circulates through the bloodstream, affecting other major organs e.g. the heart and brain, resulting in intoxication.

Blood Alcohol Concentration (BAC) and Alcohol Intoxication

The concentration of alcohol in blood (BAC) varies between individuals, depending on percentage of alcohol in drinks, level of alcohol tolerance, age, weight, gender, health status, food and other drugs taken. In general, the body can only process around one standard drink per hour. 

BAC peaks 30 to 45 minutes after one standard drink is consumed depending on the speed of absorption and metabolism.

The acute consequences of drinking alcohol depend on the BAC and are collectively termed “alcohol intoxication”; symptoms of intoxication manifest according to corresponding BAC levels.

Alcohol’s Impact on Health

Short-term health risks

Alcohol intoxication 

  • Display of various physical, mental and behavioural symptoms when one has had more alcohol than can be processed by the body. 
  • At milder levels it is characterised by drowsiness, confusion, impaired judgement or decision making, poor muscle coordination or slow response time. 
  • Serious intoxication, however, may affect vital bodily functions leading to coma and death.

Long-term health risks

Impaired gut health

  • Alcohol upsets the balance in the gut microbiome, promoting overgrowth of harmful bacteria
  • Excessive alcohol damages the cells in the intestinal lining, disrupting intestinal barrier integrity. 
  • This eventually results in leakage of pathogens from the gut into the bloodstream, and liver, where it triggers inflammation, causing acute liver disease. 
  • This also compromises the absorption of nutrients into the bloodstream e.g. essential vitamins (Vitamin A, B and E) and minerals (zinc, iron). 

 Increased risk of cancer

  • Alcohol consumption is a risk factor for cancers of the mouth, throat, colon, breast and liver. 
  • The cells lining your mouth and throat are especially vulnerable to the harmful effects of alcohol; light alcohol consumption (up to 1 drink per day) is linked to a 20% increased risk of mouth and throat cancer. 

Multi-organ damage 

  • Heart
    • Increases risk of diabetes, hypertension and heart disease
  • Liver:
    • Fatty liver, liver cirrhosis, liver failure
    • Damaged liver cannot break down fat properly; accumulation of fat in liver leads to inflammation and scarring
  • Reproductive system
    • Loss of libido, erectile dysfunction and reduced fertility 
  • Brain
    • Long term cognitive impairment and brain damage, including dementia 
  • Pregnancy Complications
    • Alcohol affects foetal development as early as the third week after fertilisation and can cause birth defects or miscarriage.

Alcohol and Medication 

Alcohol can interact with medications, intensifying medication side effects, or causing increased intoxication (refer to Table 1). 

Table 1: Drug Interactions with Alcohol
Drugs Complications arising from interaction
Heart and angina (ischemic chest pain) medications e.g. nitro-glycerine:


Rapid heartbeat, dizziness and erratic changes in blood pressure
Nonsteroidal anti-inflammatory drugs (NSAIDS): Ulceration and stomach bleeding and an increased risk of heart attacks
Blood thinners, anticoagulants (medication to prevent blood clots) e.g. Warfarin: Increased risks of internal bleeding. Heavy drinking counteracts the blood thinning properties of the blood thinners, making one more susceptible to forming blood clots and the risk of suffering a stroke
Anti-anxiety, anti-seizure and epileptic medications e.g. Lorazepam, Diazepam, Alprazolam: Impaired motor control, memory loss and abnormal behaviour
Antibiotics e.g. Metronidazole: Severe reactions such as nausea and vomiting

If you are on medication, contact your local health provider about potential interactions and refrain from taking medication and alcohol in tandem. 


Alcohol does not only lead to negative health effects over long periods of consumption, but can also impact our health during acute periods of drinking. In general, health risks rise with rising amounts of alcohol usage.

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