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Alcohol and the Digestive System

Alcohol consumption can damage the digestive system and can increase the risk of alcohol-caused cancer and liver disease.

How can alcohol damage the digestive system

Every cell in the body needs nourishment and requires the food consumed to be converted into a form that is usable by the cells. This conversion process is known as metabolism and is done by the digestive system. The digestive system is made up of many organs including; the mouth, throat, oesophagus, stomach, liver, the small and large intestines, and the anus.1 These organs each have a role in ensuring the nutrients in food can be ingested, digested and absorbed, and waste products are removed from the body.2

Alcohol can damage the organs it comes in contact with in the digestive system, including the mouth, throat, oesophagus and stomach. Once alcohol has entered the blood stream it can damage the liver and large intestines.

Alcohol is not treated like other nutrients in food. In fact, the digestive system works extra hard to eliminate it from the body,3 prioritising the elimination of alcohol ahead of other nutrients including lipids (fats), carbohydrates and proteins.4 Alcohol is absorbed throughout the digestive tract. Unlike other nutrients alcohol is absorbed directly into the blood stream through the stomach lining and it is also rapidly absorbed in the small intestine. Alcohol metabolism mostly occurs in the liver, but other cells in the body can also metabolise alcohol.5 Alcohol is converted into a toxic chemical called acetaldehyde. Alcohol can cause cancer because acetaldehyde can damage DNA and stop the cells from repairing this damage

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How does alcohol damage the mouth and throat?

The mouth and throat are exposed to alcohol as soon as ingested.6 Alcohol passes quickly into the mouths saliva, and for approximately 30 minutres after drinking, saliva contains more alcohol than the bloodstream. From saliva, acetaldehyde and alcohol easily reach and damage the tissues in the mouth.

A large Cancer Research UK study looking at lifestyle factors that cause cancer found that around a third of cancers of the mouth and throat (30%) were caused by drinking alcohol. Drinking alcohol increases the risk of oropharyngeal cancer and may increase mouth cancer risk when combined with smoking. 10

How does alcohol damage the oesophagus?

Alcohol comes into contact with the oesophagus once it has been swallowed. The oesophagus is the long tube running from the mouth to the stomach that propels food and drink down to the stomach.1112 High alcohol consumption is a risk factor for squamous cell carcinoma (cancer) of the oesophagus.1314 Alcohol can directly damage the cells lining the oesophagus (squamous cells). It can also cause acid reflux (the stomach contents to come back up into the oesophagus), which can damage cells and increase cancer risk.15

How does alcohol damage the stomach?

The stomach is the first organ to have long contact with alcohol. The stomach’s primary job is to store and mix food and drink that has been consumed.26 One-off and regular drinking can interfere with the functions of the stomach in a number of ways.17

  • Alcohol can affect stomach acid production. This can reduce the stomach’s ability to destroy bacteria that enter the stomach, which can allow potentially harmful bacteria to enter the upper small intestine.18
  • Mucous cells in the stomach lining protect the stomach wall from being damaged from the acid and digestive enzymes.19A single heavy episode of drinking can damage the mucous cells in the stomach, and induce inflammation and lesions.20
  • High alcohol content beverages (more than 15% alcohol volume) can delay stomach emptying, which can result in bacterial degradation of the food, and cause abdominal discomfort.21

How does alcohol damage the liver?

Alcohol metabolism mainly takes place in the liver. The liver filters the blood from the digestive tract and its principal role is to remove toxins from the body. The liver breakdowns alcohol in three different ways, and all three ways lead to the conversion of alcohol into acetaldehyde, which is a cell poison and causes inflammatory changes in the liver. These processes can contribute to the following damaging effects in the liver.

  • Increased fat production in the liver and this can then lead to fatty liver. 22
  • The toxic by-products produced when alcohol is metabolised can lead to cell and tissue damage, including DNA damage23

How does alcohol damage the large intestine (bowel)?

Undigested food passes from the small intestine to the large intestine where water and salts are absorbed into the body. This process can take up to 24 hours. The remains are then passed from the body through the anus.25 Alcohol can come into contact with the large intestine via the bloodstream. 26 This increases the risk of bowel cancer

  • Evidence suggests that, compared to non-drinkers or occasional alcohol drinkers, people who drink moderately (up to 4 stnadard drinks a day) and heavily (more than 4 standard drinks a day), are at an increased risk of colorectal cancer. Moderate drinkers had a 21% increased risk, and heavy drinkers had a 52% increased risk.28

     

Facts and figures

Alcohol and its metabolite (breakdown product) acetaldehyde are both classified as a Group 1 carcinogens (cancer-causing agents). This is the highest carcinogen rating, equal to tobacco smoke and asbestos.1Alcohol consumption is a risk factor for mouth, pharynx, larynx, oesophagus, breast, bowel and liver cancers.1The risk of developing these alcohol-caused cancer increases with the amount of alcohol consumed.1112

 

 

 
References

1 Vanputte, C., Seeley, R., Regan, J., Russo.,A (2011). Antamony & Physiology., p. 868

2 Vanputte, C., Seeley, R., Regan, J., Russo.,A (2011). Antamony & Physiology., p. 869

3 Insel. P., et al. (2010). Nutrition. Jones & Bartlett Publishers.

4 Insel.P., et al. (2010). Nutrition. Jones & Bartlett Publishers.

5 Preedy, V. R., & Watson, R.R. (2004). Comprehensive Handbook of Alcohol Related Pathology, Academic Press.

6 Bode, C., & Bode, J.C. (1997). Alcohol’s role in the gastrointestinal tract disorders. Alcohol health and research world. 76-83. P.77

7 Singer, M.V. & Brenner, D. (ed) (2006). Alcohol and the Gastrointestinal tract. Karger Medical and Scientific Publishers

8 Singer, M.V. & Brenner, D. (ed) (2006). Alcohol and the Gastrointestinal tract. Karger Medical and Scientific Publishers.

9 A Singer, M.V. & Brenner, D. (ed) (2006). Alcohol and the Gastrointestinal tract. Karger Medical and Scientific Publishers.

10 http://www.cancerresearchuk.org/about-cancer/type/mouth-cancer/about/risks/definite-risks-for-mouth-and-oropharyngeal-cancer#vwDTlBAZF8qmLerd.99

11 Vanputte et al. Anatomy text book., p. 869.

12 Porth, C. (2009). Pathophysiology . 891.

13 Porth, C. (2009). Pathophysiology . 890.

14 Vioque, J.et al. (2008).

15 Bode, C., & Bode, J.C. (1997). Alcohol’s role in the gastrointestinal tracty disorders. Alchol health and research world. 76-83. P.77

16 Vanputte, C., Seeley, R., Regan, J., Russo.,A (2011). Antamony & Physiology., p. 882

17 Bode, C., & Bode, J.C. (1997). Alcohol’s role in the gastrointestinal tract disorders. Alcohol health and research world. 76-83. P.78

18 Bode, C., & Bode, J.C. (1997). Alcohol’s role in the gastrointestinal tract disorders. Alcohol health and research world. 76-83. P.79

19 Vanputte, C., Seeley, R., Regan, J., Russo.,A (2011). Antamony & Physiology., p. 882.

20 Bode, C., & Bode, J.C. (1997). Alcohol’s role in the gastrointestinal tract disorders. Alcohol health and research world. 76-83. P.79

21 Bode, C., & Bode, J.C. (1997). Alcohol’s role in the gastrointestinal tract disorders. Alcohol health and research world. 76-83. P.79

22 Duggan, A.E & Duggan, J.M (2011) Alcoholic liver disease. Assessment and management.

23 Koop, D.R (2006). Alcohol metabolism’s damaging effects on the cell. Alcohol research & health, 274-280

24 Setshedi, M., Wands, J.R., & de la Monte, S. (2010). Acetaldehyde adducts in alcoholic liver disease. Oxid Med Cell Longev, 3(3): 178–185.

25 Vanputte, C., Seeley, R., Regan, J., Russo.,A (2011). Antamony & Physiology.., p. 902

26 Colditz, G. (ed.) (2007). Encyclopaedia of cancer and society. SAGE publications

27 Shrubsole, M.J. (2008). Alcohol Drinking, Cigarette Smoking, and Risk of Colorectal Adenomatous and Hyperplastic Polyps. 167(9), DOI: 10.1093/aje/kwm400

28 Fedirko, V., et al (2010). Alcohol drinking and colorectal cancer risk: an overall and dose–response meta-analysis of published studies. Annals of Oncology 22: 1958–1972, doi:10.1093/annonc/mdq653.