How alcohol affects your digestion
Welcome to episode 68 of the Inside Knowledge podcast for people with IBS. I’m Anna Mapson. So, this week is all about alcohol and how what you drink affects your digestion. This is one of the topics that, for some clients that I work with, can be particularly challenging. Alcohol is either an important part of the way that you socialise with your friends—which tends to be more common with younger people, like students, or people in their 20s—or it’s one of the ways that you’ve learnt to relax, particularly if you’re in your 40s or 50s. So you enjoy a drink at the end of the day.
These are the two groups of people I work with who tend to have the highest alcohol consumption and the biggest issues with reining it in or making changes. I’m going to say right at the beginning as well that I am somebody who drinks alcohol. I drink a lot less than I used to, but I do still enjoy occasional drinks. So I just want to put that out there first off. I know this episode won’t be relevant to a lot of people if you don’t drink at all, and there’s a growing movement of people who are choosing to give up alcohol because of the impact that it has on their lives.
I’m going to speak specifically about the digestive consequences of alcohol, but I also want to acknowledge that there are other factors too. There’s the financial implication of drinking a lot, the mental health implications of being disinhibited frequently, and how you might come to rely on it in social situations. That’s another whole topic. Today, let’s just focus on some of the things alcohol can do to your digestion.
Dehydration and its impact on digestion
I wanted to start with the obvious one, which is dehydration. When we drink alcohol, we tend to feel dehydrated the next day. That’s one of the key symptoms of a hangover. Alcohol stops the production of an antidiuretic hormone, which means you get a diuretic effect. Diuretic means you’re losing water—you tend to need to go to the toilet more than you would normally. Your body just wants to get rid of the alcohol as quickly as possible. Your liver has to break down the alcohol into acetaldehyde, and some people have a genetic mutation that means they struggle with the toxicity of this compound.
This might be why some people have a predisposition to quick flushing. You might just have a couple of sips of wine and already feel really red in the face, maybe a bit giddy, or fuzzy-headed. Some people will respond much quicker to alcohol because of how their liver works. Some people just don’t respond well to it.
Why alcohol can be worse for people with IBS
The reason this is an issue for people with IBS is that if your liver is already processing a higher amount of toxins—maybe because you’ve got bacterial overgrowth, you’re slightly dehydrated, or you’re low in key nutrients like zinc or iron—your organs aren’t functioning as well as they could. Adding alcohol into that mix can make it harder for your body to detox.
We know that people who abuse alcohol over time can develop cirrhosis of the liver, which involves damage to liver cells and, in extreme situations, liver failure. But even in less extreme cases, the liver has to work hard to process alcohol. This is especially relevant for people with IBS because of how alcohol can affect gut motility.
Alcohol’s effect on gut motility
If you’ve ever woken up with a hangover and diarrhoea, and you’re someone who normally has constipation or a slow transit time, alcohol can really speed things up. Alcohol can stop something called the impedance wave, which keeps food in the small intestine longer so we can absorb nutrients. When this wave is reduced, food moves quicker through your gut. This means you absorb fewer nutrients.
For someone with IBS, if you already have issues with fast motility and diarrhoea-predominant symptoms, alcohol can exacerbate this, causing cramping and more pain. Because alcohol irritates the gut lining, some people with IBS may experience reduced carbohydrate absorption. This means food moves through even quicker, leaving less time for it to be properly broken down. It ferments in the gut, leading to symptoms like smelly stools or diarrhoea the next day—even if that’s not your usual symptom pattern.
Alcohol, anxiety, and the gut-brain connection
Another way alcohol can worsen IBS is through its impact on anxiety. It’s common to feel anxious the morning after drinking. This might be due to changes in the gut-brain connection or alterations to your gut microbes. Certain gut microbes can be temporarily altered after a night of drinking, and this can affect your mood.
The more anxious we feel, the more likely we are to experience heightened gut symptoms. Anxiety can change digestive speed and increase our awareness of pain. Alcohol can also reduce microbial diversity in the gut, which has been linked to increased inflammation and anxiety. For people who drink heavily over a long period, this microbial imbalance can cause even more issues.
Alcohol and gut permeability
Alcohol can increase gut permeability by loosening the tight junctions between your gut cells. This means more endotoxins can enter your bloodstream, leading to inflammation throughout the body. For people with IBS, this can heighten sensitivity to certain foods for a day or two after drinking.
While reflux and heartburn aren’t officially part of IBS, they’re common issues I see in my clients. Alcohol can weaken the lower oesophageal sphincter, the valve that stops acid from moving upwards. This can lead to heartburn, particularly if you’re lying down or drinking heavily. Alcohol also increases acid production, which can make reflux worse.
Choosing the right drink if you have IBS
If none of this has put you off having a drink, let’s look at which drinks are better or worse for people with IBS. Unfortunately, there’s no perfect IBS-friendly alcoholic drink. Fermented drinks like wine are higher in FODMAPs, which can cause bloating, pain, and gas. Monash University suggests one small glass of wine—150ml—should be okay. Beer is also safe in small quantities, but only up to 330ml.
Spirits like gin and vodka are generally safer at one shot. However, be cautious about mixers, as many are high in FODMAPs. Soda water with lime or cordial is often a better choice than sugary juices. Avoid rum and cider, as they’re both high FODMAP and more likely to trigger symptoms.
Alternative ways to relax
If you find it challenging to give up alcohol, it might be worth exploring other ways to relax. Many clients have found success with mocktails or non-alcoholic drinks tailored to their preferences. It’s not just about cutting out alcohol; it’s about replacing it with something enjoyable.
You might also want to explore why you feel stressed and why alcohol is your go-to for unwinding. If you rely on a nightly glass of wine, that might be a sign to find other ways to manage stress, such as mindfulness or creating a relaxing evening routine.
How much is too much alcohol?
The UK guidelines recommend no more than 14 units of alcohol per week, spread over three days, with at least three alcohol-free days. To put this into perspective, one pint is around two units, one shot of spirits is one unit, and a small 175ml glass of wine is about 2.3 units. If you’re pouring your own wine at home, you’re likely pouring a large glass, which counts as two smaller glasses. It’s easy to overshoot the 14-unit maximum.
Tips for minimising the impact of alcohol
To reduce alcohol’s impact on your digestion, drink water alongside alcohol to stay hydrated. Avoid drinking on an empty stomach, as this increases absorption speed. Eating protein and fibre the next day can help stabilise blood sugar and support gut bacteria. Consider electrolyte drinks or foods high in potassium and sodium to rehydrate.
Finally, think about your alcohol consumption habits and whether they’re helping or harming your health. Even small changes, like reducing your intake or choosing lower FODMAP options, can make a big difference to your digestion and overall well-being.
Anyway, that’s probably another whole podcast edition I could do on how to manage a hangover when you’ve got IBS. But for today, I hope that’s been helpful in terms of understanding a little bit about
- what alcohol does to your digestion,
- the types of drinks that you can potentially have,
- and what they do to your body.
- the guidelines for drinking alcohol
- tips for managing with IBS.
If you found anything there, you’d like to ask me more about, please do send in some questions. That can be to my email address, info@goodnessme-nutrition.com
Don’t forget to follow me on Instagram, where I am @goodnessme_nutrition. Okay, thanks for listening to this episode of the Inside Knowledge. Better digestion for everyone.