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Does drinking alcohol cause constipation?

Clare 4 years ago

As with most other aspects of health, the effect that alcohol has on someone varies from person to person as we are all unique. However, one thing we know for certain is that drinking affects our digestive system in many ways and one of the results may indeed be constipation.


The main way in which alcohol causes constipation is that it dehydrates you. It may be useful to understand why this happens – after all, beer is 95% water! However, when you drink a beer, you expel the amount of water that is in the beer plus an additonal amount. Why is this? Alcohol interferes with the mechanism that controls the water levels in our body. Normally the body can sense when water levels are low and salt levels are more concentrated. The pituitary gland is then stimulated to produce ADH (Anti Diuretic Hormone) which in turns stops you from urinating. However, alcohol does the opposite. It actually encourages you to urinate meaning that you lose water. Alcohol forces your kidneys to produce more urine per hour than it normally would, leaving you dehydrated1. Once you are dehydrated, the body will start to draw water out of the large intestine for essential metabolic reactions, which in turn leaves the colon empty of water and the stools become hard and dry. As we know, dehydration is one of the main causes of constipation.


Another way in which alcohol may make you constipated, is that it diminishes the wave-like motions that propel food along the digestive tract2. After all, alcohol is a known depressant and so dampens the intestinal nerves responsible for moving things along. And let’s not forget that when we drink we tend to want to nibble on nibbly things that often contain gluten. When digested, gluten is converted into an opioid that also affects the motility of the gut!3

Gut bacteria

Finally, let’s not forget our gut bacteria – small they may well be – but important they are also. Gut bacteria may be affected by drinking as well. We know that alcohol can kill pathogenic bacteria - wine, for example, has been found to help combat H.pylori4. However, alcohol is indiscriminate and can therefore destroy our healthy bacteria as well, which in turn affects our digestion of food and inflammation levels of the gut wall. A healthy balance of bacteria is needed for healthy excretion, so this too may affect constipation. Remember even moderate drinking can cause gut dysbiosis5.


Make sure you are fully hydrated before you start drinking
We all react differently

To make matter worse, it is worth noting that our gut flora metabolizes alcohol into the intermediary chemical form acetaldehyde, increasing this metabolite along the whole length of the intestinal tract. This is a highly inflammatory and carcinogenic substance which might explain why the gut wall of heavy drinkers is often damaged6. Acetaldehyde is very toxic so it is passed straight to the liver to be detoxified. The liver then converts it to acetate which is then excreted. Only a certain amount of alcohol can be metabolized by the liver per hour, so if you are drinking a lot it can cause a backlog and, often this is when people are unwell or sick. So, for example, if you binge drink it is possible that despite being dehydrated (due to alcohol being a stomach and gut irritant) and the liver working overtime to expel what is essentially a poison, drinking heavily may cause diarrhoea, instead of constipation. Some people may vomit. 

So how do we reduce becoming constipated when drinking?

  • Well, sadly the most obvious answer is probably the one you least want to hear - properly considering your alcohol intake is paramount. Regularly drinking a lot of alcohol is likely to cause long term imbalances which may be hard to undo. Constipation, depression and heavy drinking often go hand in hand. Imbalanced gut bacteria and leaky gut7 can also be caused by constant heavy drinking. Giving your digestive system a rest from alcohol is therefore very beneficial. Aim for 3 days a week at least.
  • However, if it’s the odd night out socialising that causes you to be constipated, try making sure you are completely hydrated BEFORE you go out. Keep drinking water whilst you are drinking as well. The alcohol will still persuade your body to expel water, but it's less likely to impact so much on your bowels – and may even keep that thumping head at bay. 
  • The dehydration caused by drinking also upsets the electrolytes in our body. The body requires these to function so is likely to try to take them from the stool, further drying them out and making them hard to pass. Drinking an electrolyte drink in the morning may help. Coconut water is a lovely natural electrolyte drink.
  • Look after your liver. Try taking Milk Thistle and drinking dandelion tea which both help with liver function and detoxification.
  • Keep moving. This is a classic. Exercise is a well known gut stimulant so running off a hangover will help get your bowels moving too.
  • Take a probiotic if you drink regularly as this will help replete your healthy gut bacteria.

Read Exercise can relieve constipation and Foods that can cause constipation for more interesting information on alleviating constipation.

Happy Health!



1.ABC Science (http://www.abc.net.au/science/articles/2012/02/28/3441707.htm)

2.Luis Bujanda (2000) The effects of alcohol consumption upon the gastrointestinal tract The American Journal of Gastroenterology 95, 3374-3382 (December 2000) | doi:10.1111/j.1572-0241.2000.03347.x

3.Bishop, H., Frazer, A. C., Robinson, G. B., & Schneider, R. (1963). The nature of the antiperistaltic factor from wheat gluten. British Journal of Pharmacology and Chemotherapy, 21(2), 238–243.)

4. Luis Bujanda (2000) The effects of alcohol consumption upon the gastrointestinal tract. Effects of Alcohol Upon the GI Tract The American Journal of Gastroenterology 95, 3374-3382

5. American College of Gastroenterology. (2011) Moderate alcohol consumption is associated with small intestinal bacterial overgrowth, study finds. ScienceDaily. 2011/10/111031114949.htm

6. Mikko Salaspuro (2009) Acetaldehyde as a common denominator and cumulative carcinogen in digestive tract cancers. Scandinavian Journal of Gastroenterology, Vol 44, Issue 8

7. (Elhaseen E Elamin, Ad A Masclee, Jan Dekker, Daisy M Jonkers (2013) Ethanol metabolism and its effects on the intestinal epithelial barrier. Nutrition Reviews 1 July 2013 DOI: http://dx.doi.org/10.1111/nure.12027)



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