Effects of alcohol abuse

Blood Alcohol Concentration (BAC) is the amount of alcohol found in the blood stream and reported as weight of ethanol in grams per unit of blood volume. The table below shows how different concentration of alcohol in our body affects us.

Table 1. Shows stages of alcohol intoxication. Source: https://www.intox.com/t-physiology.aspx

Moderate consumption of alcohol is known to be therapeutic for example decrease the risk of heart disease and the cleansing and flushing out of the kidneys. Alcohol abuse can cause acute or chronic effects depending on how dependent an individual is on alcohol. Acute effects are associated with domestic violence, loss of workplace productivity, society crime, traffic accidents and public disorders. Chronic effects are related to chronic health problems like cancer, liver disease, stroke, respiratory disease, diabetes and bone disease (Manzo-Avalos and Saavedra-Molina, 2010).



Metabolism of alcohol continue…

Alcohol can be metabolised by both oxidative and non-oxidative pathways. Oxidative pathway involves the three enzymes (ADH, cytochrome P450 and catalase enzyme) mentioned in the previous post and the diagram as well. The products of this pathway are Acetaldehyde and Acetate both of which are toxic to cells and tissues. Acetaldedhye is further metabolised to acetate and NADH by ALDH2 as it is shown in the diagram (refer to previous post). Acetate is then oxidised to carbon dioxide (CO2) in the liver, heart, brain an skeletal muscle.

Non-oxidative pathway:

Ethanol is nonoxidatively metabolized by two pathways
Fig 2. Non-oxidative pathway of alcohol metabolism by human body. source

The by-products of this pathway are fatty acid esters (FAEEs) by FAEE synthease and phosphatidyl ethanol by phospholipase D.

The metabolism pathways provided here are just a quick outline of how alcohol is metabolised. I will post more on how these by-products harm human tissues.




Routes of Ingestion and Metabolism of Alcohol

Alcohol is normally ingested by drinking it. But there are other routes of alcohol ingestion as mentioned in HAMs which are as follows:

  • inhalation: vaporised alcohol can be inhales and lead to intoxication 10 times faster than drinking.
  • transdermal: this is a slow method and the alcohol is absorbed through the skin.
  • Alcohol enema and injection: these two methods are extremely dangerous as alcohol is rapidly absorbed. the risk of alcohol poisoning is very high.

When orally ingested, alcohol passes through the gastrointestinal tract. it is absorbed primarily from the small intestine into the veins collecting blood from the stomach, bowels and the portal vein. Through the portal vein it enters the liver where it is metabolised by the enzymes (Zakhari, N.D). Liver is the main organ where metabolism occurs while stomach also helps.

alcohol metabolism
Fig.1 Metabolism of alcohol (Oxidative pathway) by three enzymes- Alcohol dehydrogenase, cytochrome P450 and catalase. (Source of image: http://pubs.niaaa.nih.gov/publications/arh294/245-255.htm)


Medical consequences of alcohol abuse

Alcohol is one of the oldest drugs known and very easily available. Alcohol transports to all parts of the human body from digestive tracts via the blood vessels. It affects every organs of the body including the brains. While controlled or small quantity consumption may not affect the health and instead help improve health, excessive alcohol intake cause various tissue injuries, interfere with hormonal and biochemical regulations of cells and metabolic functions. Alcohol interrupts the neurotransmitter and the receptors.

The following are some medical consequences of alcohol abuse:

  • Accidental injuries
  • skeletal syste
  • gastrointestinal system
  • hepatic system
  • cardiovascular system