What alcohol does to your gut health

Telegraph

22-03-2025

We all know that a healthy gut is vital for everything from fighting off colds and flu to conditions such as anxiety, depression, irritable bowel syndrome and more. We also know that eating a wide variety of plants, fermented foods and fibre will improve and maintain our gut health.
Yet, unfortunately, even if we're maxing out the kefir and kombucha, much of the good work is undone by a boozy dinner party or a few beers in the pub. Alcohol is uniquely harmful to our gut microbiome.
'Consuming alcohol can affect gut health in the short and long term. It can do this in several ways – by disrupting the balance of the gut bacteria, by triggering irritation and inflammation, impacting nutrient absorption and digestion and driving up the risk of gut-related health problems such as ulcers and gastritis for example,' says Dr Emma Derbyshire, a leading nutritionist.
An unhealthy, unbalanced gut will also affect the health of our brain and liver, as the two are closely linked and in constant conversation.
So why is alcohol so troublesome for gut health? Do we have to give up drinking completely, and if not, what can we do to mitigate its effects?
All the ways in which alcohol affects our gut health
1. It impacts your digestion
'This is because alcohol is rapidly absorbed; unlike food, it doesn't need to be broken down and digested. Instead, it is absorbed from the stomach and small intestine directly and quickly enters the bloodstream. Even a single drink may alter stomach acid production,' says Dr Derbyshire.
Drinking also causes the gut-related symptoms of diarrhoea or constipation that are familiar friends after a big night out.
'Alcohol can impact the nerves lining the gut, causing your digestion to speed up, alongside more water being pulled into the gut, leading to loose stools. Most people will notice this when they've had a heavy drinking session, that they'll need to go to the bathroom earlier, and have altered bowel movements,' says Dr Emily Leeming, a scientist at King's College London and author of Genius Gut.
2. It affects how well nutrients and vitamins are absorbed
The speeding up of the digestion can also mean that nutrients from food are less well absorbed.
'Alcohol can directly impede the absorption of water-soluble vitamins such as B1, B6, B12 and folate in the intestines. Calcium and vitamin D metabolism can also be disrupted by alcohol, which can affect bone density and increase osteoporosis risk,' says Dr Derbyshire.
3. It makes bloating and stomach pain worse
For people who already suffer from gut-related issues such as bloating, gas, stomach pain, cramps and IBS, drinking alcohol is also likely to make those symptoms worse.
And it's not just the drinking itself that can impact the gut but the side effects associated with drinking.
We know, for example, that drinking can lead to a poor night's sleep, which is also linked to a less diverse and healthy microbiome. Bad sleep often leads to cravings for high-fat and sugary hangover-fuelled foods the next day, which in turn is also bad for our guts.
How drinking heavily impacts your gut
Alcohol's impact on your gut will clearly be more profound if you drink regularly and heavily. Studies have shown that heavy drinking alters the actual makeup of gut bacteria, leading to an imbalanced gut, known as dysbiosis. This can lead to inflammation and disease.
'Ethanol, the main ingredient in alcohol, can kill off some of the microbes, which is why it's used in high strengths as a hand sanitiser. Alcohol creates a toxic environment that favours harmful microbes while making it harder for 'good' ones that support digestion and immunity to survive,' explains Dr Leeming.
Some studies have also suggested that this imbalance of gut bacteria can also alter the brain and mood, increasing cravings for booze.
Not only does alcohol kill off the good bacteria, but over time it also weakens the protective lining of our gut, leading to what is often called 'leaky gut.' This is when little gaps open up in the gut lining, which means that bacteria, in digested food particles and other nasties can get into our bloodstream, possibly causing problems in the rest of our body.
'The liver receives about 75 per cent of its blood directly from the gut and it's a power house of metabolism. So, if you damage one, you have an impact on the other. It's a sort of gut-liver-immune axis, and it is really important in explaining how alcohol influences our health,' says Dr James Kinross, a consultant surgeon at Imperial College London and the author of Dark Matter: The New Science of the Microbiome.
So how much alcohol is safe for our gut?
For those of us who enjoy a drink, the extensive evidence of the harmful effects of alcohol on our guts makes for pretty depressing news. Yet experts say that drinking in line with the current recommendations, which in the UK is no more than 14 units of alcohol per week for men and women, should be fine to maintain a healthy gut.
Others, however, suggest a lower intake. 'Occasionally drinking a small amount of alcohol likely doesn't do any long-term damage, especially if you're eating a balanced healthy diet, have an active lifestyle and manage stress levels. Where possible, though, choose an alcohol-free or low-alcohol option,' says Dr Leeming. Binge drinking is especially bad for our guts.
It is also the case that our tolerance for alcohol does go down as we get older, which could be a result of the corresponding decline in our gut diversity as well as other changes.
'As we age, we have reduced enzyme activity and reduced liver function. Together this slower rate of alcohol metabolism can make the effects of alcohol last longer and feel stronger,' says Dr Derbyshire.
Are some drinks better for our gut than others?
Researchers used to believe that drinking a small amount of alcohol was actually good for us and led to a more diverse, healthy gut microbiome.
Yet they now think those effects are because moderate drinkers are more likely to be people who are better off and therefore have a healthier lifestyle overall.
'In an ideal world, the science is pointing towards limiting alcohol intake overall being the best route, but if you are going to drink, red wine might still be a less harmful option. This is because red wine gets its colour from anti-inflammatory polyphenols called resveratrol, which may be able to mitigate some of alcohol's harmful effects,' says Dr Emily Leeming.
Beer, sugary cocktails, and sweet and dessert wines are not good choices, however.
'Beer, because of its levels of carbonation and gluten content, can heighten inflammation in the gut and disrupt the balance of bacteria. Sugary cocktails can also contribute to dysbiosis and tend to be acidic and often contain artificial additives that could also upset the gut. Sweet and dessert wines also tend to have a higher sugar content, be acidic and may contain sulphites which can trigger digestive issues,' says Dr Derbyshire.
Clear spirits have lower sugar levels, but they are also absorbed much more quickly into the blood stream.
How to lessen the effects of drinking on the gut
As well as cutting down on your drinking, there are many strategies to minimise the effect of alcohol on your gut.
1. Max out on fibre and protein
Eating something with fibre and protein before drinking, like a bowl of yogurt and nuts or a piece of wholegrain toast and peanut butter, can create a protective layer in your stomach and slow down how fast the alcohol is absorbed.
2. Take a water break
Alternating an alcoholic drink with water is a tried and tested technique to reduce drinking and avoid dehydration, and having a few drink-free days also allows your gut microbiome some time to recover.
3. Eat prebiotic and probiotic foods
Eating gut-healing, fibre-rich foods regularly to boost gut health is also a good idea. 'Prebiotic foods that help to feed favourable gut bacteria such as garlic, bananas, onions and asparagus can help to offset some of the inflammatory effects of alcohol. Probiotic foods can help restore the natural balance of bacteria in your gut. So, eating the likes of kefir, natural yogurt or sauerkraut before drinking could be beneficial,' says Dr Derbyshire.
4. Consider taking a supplement
If you're worried about your gut health and regularly suffer from symptoms of poor gut health, some experts also advise taking a targeted probiotic supplement.
'Try a scientifically studied probiotic to balance your gut microbiome, which helps to provide reassurance of mind that the gut is receiving a supply of favourable bacteria,' says Dr Derbyshire, especially on days when the right foods, or time to find them, are just not available.
And overall, having a healthy lifestyle is also essential for a happy gut. So protect the gut/brain axis by managing stress, exercise regularly and maintain good relationships. Your gut will thank you for it.