What drinking alcohol really does to your bowels — and the secret to avoiding hangover poos

Your post-party toilet habits explained...

What drinking alcohol really does to your bowels — and the secret to avoiding hangover poos
This is what alcohol is really doing to your bowels
Listen up (Picture: Getty)

Maybe you’ve spent the last 10 days celebrating the end of Dry Jan and feeling a bit worse for wear this week because of it.

There’s no denying a boozy evening can leave our bodies feeling all kinds of ways– not just with hangiety (as well as an actual hangover itself), but things can feel slightly unsettled in our stomachs, too.

That’s because alcohol can affect your bowels in various ways, from diarrhoea and constipation, but it goes further than this too.

After all, with gut health going from cringe to cool over recent years (and rightly so with all its numerous benefits), we’ve never been more conscious of it.

So what are those pints or glasses of red wine really doing to our bowels? And what can we do to limit the chance of a day on the loo after a big night out?

Dr Megan Rossi, known as The Gut Health Doctor to her 494,000 Instagram followers, gives Metro.co.uk the lowdown on what happens when we drink….

It all starts in the stomach

Pelvic pain
Acid reflux? We know her! (Picture: Getty)

Well, it all starts in the stomach – and is often why we sometimes get bad acid reflux after drinking (white wine, we’re looking at you).

She explains: ‘When we drink alcohol, it goes down our food pipe (AKA, the oesophagus) and into our stomach. Alcohol can make the trapdoor that connects the stomach and the oesophagus (known as the oesophageal sphincter) relaxed, and that’s why your risk of reflux (where acid moves in the wrong direction i.e. from your stomach into your acid-sensitive oesophagus) is increased when you drink alcohol.’

Dr Megan explains the absorption of alcohol from your gut into your blood system takes place both in the stomach and in the small intestine. And once this happens, it’s transported around your body and to your liver where it’s broken down.

If you drink on an empty stomach, more alcohol is absorbed into the blood (studies have shown around 25% more than on a full stomach). Whereas, if you’ve eaten before drinking, the rate of alcohol absorption slows down.

Dr Megan recommends enjoying high fibre foods before a night on the town, as the fibre helps slow down the alcohol absorption, and therefore results in a lower peak in your blood alcohol concentration.

But why does that matter? 

Dr Megan explains: ‘The higher the concentration of alcohol in your blood system at any one time means the harder your liver has to work to break it down, the more alcohol-triggering “inflammation” and therefore the worse the hangover potential.’

The surprising role of your gut-liver axis

But a surprising factor in this is that your gut microbes also play in helping your liver break down alcohol.

‘New research suggests that they support the work of the liver – the so-called gut-liver axis,’ explains Dr Megan.

‘While our knowledge of the gut-liver axis is still in the early days, one study showed that giving people with liver disease a daily poop transplant (transplanting the healthy bacteria of someone without liver disease to someone with liver disease) helped improve their liver function.

‘Therefore it makes sense that looking after your gut microbes by nourishing them with a diverse range of plants may indeed help support your liver health.’

How it affects your poo

Woman using toilet in morning
The morning after a drinking session can be bad (Picture: Getty)

Another way alcohol affects our bowels is that it directly irritates the gut lining and muscles.

Megan says this can lead to the very ominously-sounding ‘leaky gut.’

She adds: ‘This essentially means that dietary and microbial components that normally can’t get from your gut into your blood are more able to penetrate the gut barrier. This in turn can lead to increased inflammation throughout the body.

‘The effect of alcohol on your gut lining and also gut muscles (yes, alcohol impacts how food moves through your gut too), is what leads to loose stools that many people experience anywhere between 4-12 hours after alcohol.’

This ultimately explains where hangover poos come from, too.

Dr Megan also stresses that while some alcoholic drinks, like red wine and dark beers have been ‘associated with some health benefits, this is mostly down to the plant components known as polyphenols found in them’.

She adds: ‘These polyphenols move through most of our 9-metre digestive tract undigested where they reach that final part called the large intestine. This is where most of the gut bacteria live. The gut bacteria part-digest these plant chemicals and in turn produce various compounds which have shown to have anti-inflammatory effects.’

However, this isn’t an excuse to load up on on red wine and Guinness, she warns.

Dr Megan continues: ‘After more than one or two glasses, the pro-inflammatory alcohol component of those drinks tends to override those anti-inflammatory polyphenol benefits, leading to a net increase in negative outcomes.’

4 main barriers to good gut health:

  1. Diets that are high processed and ultra processed foods, added sugar and refined fat, and low in fibre.
  2. The cost of living is driving up prices of fruit and vegetables and other foods that contribute to a gut-friendly diet.
  3. People don’t know how important fibre is for their health, and which foods contain it.
  4. Lifestyle factors, including physical activity, smoking, alcohol, stress, sleep and use of unnecessary antibiotics.

Alex Glover, Nutrition Development Lead, Holland & Barrett.

Do you have a story to share?

Get in touch by emailing [email protected].

MORE : How to manage your gut health during a festival

MORE : Work your guts out: How specific exercises might improve gut health and help manage IBS