‘Gut-friendly’ foods such as sourdough bread and kimchi come hand in hand with claims they can improve digestion, immunity and overall well-being.
But experts, speaking to the Daily Mail, say many people overlook one key factor: what they drink can make or break their gut health, too.
And while some beverages can support the gut microbiome, others may quietly sabotage it – triggering bloating, discomfort and fatigue, and potentially contribute to longer-term health problems.
It’s not just the usual suspects of alcohol and sugary fizzy drinks, adds Rhiannon Lambert, nutritionist and best-selling author of The Fibre Formula.
‘Our gut microbiome is influenced by many factors, including what we drink. We now have research to suggest some drinks may negatively impact gut health when consumed frequently or in high amounts,’ she says.
The gut is home to trillions of microbes – mainly bacteria, but also viruses and fungi – known as the gut microbiome.
These microbes help break down food, support the gut lining and produce compounds that influence digestion, inflammation, metabolism and immune function.
When the microbiome is in balance, beneficial bacteria help keep the gut stable and suppress more harmful strains.
Drinking alcohol can disrupt the balance of gut bacteria, which may promote inflammation
But when that balance shifts – a state sometimes called dysbiosis – it can lead to symptoms such as bloating and irregular bowel habits, and has been linked in research to conditions including weight gain, type 2 diabetes and heart disease.
And what you drink can push things either way.
Some beverages may feed beneficial bacteria, help microbes produce protective compounds, and support hydration – all of which can promote a healthier gut environment.
Others may irritate the gut lining, disrupt the microbiome and create conditions where ‘bad’ bacteria thrive.
Nutritional therapist Hanieh Vidmar says consistency matters more than trends, and that water, herbal teas, lightly brewed green tea and fermented drinks like kefir or kombucha are generally the best choice.
She says: ‘The healthiest drinks for the gut are usually the least exciting ones.
‘They’re low in additives, low in sweeteners, and easy for the digestive system to handle.’
With this in mind, we asked leading nutritionists to reveal the worst drinks for gut health – and some healthier swaps worth trying instead.
Coffee can cause heartburn, stomach cramps, or worsen irritable bowel symptoms
Trendy juice shots
Juice shots are often sold as ‘gut shots’ – but experts warn they can backfire.
They’re typically high in concentrated sugars, low in fibre, and acidic enough to trigger reflux or stomach irritation in some people.
Rob Hobson, registered nutritionist and author of The Low Appetite Cookbook, says: ‘These juice shots are often marketed as ‘gut shots’, but from a digestive health perspective, they’re probably far from ideal for everyone.
‘They are highly concentrated, acidic and low in fibre, which can irritate the stomach lining and trigger reflux, nausea or abdominal discomfort, particularly when taken on an empty stomach.
‘Ingredients like ginger and turmeric have some evidence-backed benefits in food form, but there’s not much evidence that small, concentrated liquid shots meaningfully improve gut bacteria.
‘For some people, they may do more harm than good.’
Oat milk
Oat milk isn’t inherently unhealthy – but experts say some versions can be harder on digestion.
Many commercial ‘barista’ products contain added oils, thickeners and gums to improve texture, which may irritate sensitive guts.
Certain emulsifiers are also being studied for their potential to disrupt the gut’s protective mucus layer and increase intestinal permeability.
Ms Vidmar says: ‘Oat milk isn’t inherently bad, but many commercial ‘barista’ versions are highly processed and contain added oils, gums and enzymes.
‘These can be irritating for some people’s digestion. It also tends to be higher in rapidly absorbed carbohydrates, which can spike blood sugar and indirectly affect gut health.’
Unfiltered coffee
Coffee affects the gut in a different way: it can stimulate stomach acid and speed up gut motility.
That may help some people stay regular – but for others it can worsen reflux, cramps or IBS symptoms.
Dr Federica Amati, one of the nutritionists behind the ZOE Diet, says: ‘Unfiltered coffee, such as French press or Turkish coffee, contains compounds called cafestol and kahweol, which can raise LDL cholesterol.
‘Coffee also stimulates the digestive system, increasing stomach acid and gut motility.
‘While this can support bowel regularity for some, it can also lead to heartburn, stomach cramps, or worsening of irritable bowel symptoms in others.’
‘Diet’ or ‘zero sugar’ drinks
Sugar-free fizzy drinks may feel like a healthier option, but experts say the impact on gut health is less clear-cut.
Ms Lambert says evidence suggests responses to artificial sweeteners vary – depending on the type used, the dose, and a person’s existing gut bacteria.
‘Some studies have found changes in gut microbes and glucose control in a subset of participants, while others show no effect,’ she says. ‘This suggests people may respond differently, rather than there being one universal outcome.’
She adds that some ultra-processed drinks also contain additives such as emulsifiers, which are being investigated for their potential effects on gut bacteria.
‘Since people appear to respond differently, they’re best treated as an occasional swap rather than a daily option, with water forming the foundation of hydration.’
Mr Hobson agrees: ‘These diet drinks are often marketed as the ‘healthier’ option but the evidence around artificial sweeteners and gut health is increasingly mixed.
‘Sweeteners such as sucralose, saccharin and aspartame have been shown in both human and animal studies to alter the composition and function of gut bacteria.
‘Some research suggests they may impair glucose tolerance by disrupting the microbiome, and many people report bloating or altered bowel habits when consuming them regularly.
‘They’re unlikely to be harmful in small amounts, but daily intake may not be very gut-friendly.’
Beer and lager
It comes as little surprise that alcohol has one of the strongest evidence bases for gut-related harm.
Studies suggest regular drinking can increase intestinal permeability – often referred to as ‘leaky gut’ – and disrupt the balance of gut bacteria, which may promote inflammation.
The effects are dose-dependent, meaning how much you drink – and how often – makes a difference.
In the UK, health chiefs advise adults not to regularly exceed 14 units per week.
And while alcohol itself is the main issue, some drinks can be particularly harsh on digestion.
Lager and beer, for example, combine alcohol with carbonation and fermentable carbohydrates – a mix that can worsen bloating and trigger symptoms in people with sensitive guts.
Diet drinks are often marketed as the ‘healthier’ option but are still packed with chemicals
Mr Hobson says: ‘Alcohol is a known disruptor of gut health. It increases intestinal permeability, promotes inflammation and alters the balance of gut bacteria, reducing levels of beneficial species.
‘Beer can be particularly problematic due to its combination of alcohol, fermentable carbohydrates and carbonation, while spirits with sugary or diet mixers add further stress to the gut.’
Oh don’t assume alcohol-free options are automatically ‘gut-friendly’ – many non-alcoholic beers are surprisingly high in sugar.
Sugar-sweetened drinks
Ms Lambert warns sugar-sweetened soft drinks can alter the balance of bacteria in the gut – reducing beneficial strains and shifting the microbiome in a less healthy direction.
She says: ‘Diets high in added sugars have been associated with reduced bacterial diversity, which is an important feature of a healthy gut and plays a role in supporting immune function, digestion and even aspects of mental wellbeing.’
Mr Hobson adds: ‘Sugary soft drinks contain large amounts of free sugars with no fibre or beneficial compounds to support the gut microbiome.
‘Regular intake of these drinks has been linked to reduced microbial diversity and a shift towards bacteria associated with inflammation and metabolic disease.
‘Their acidity can also irritate the gut lining, while carbonation may worsen bloating and gas, particularly in people with sensitive digestion or IBS-type symptoms.
‘It’s not that you should never drink them, but it’s better for your health if they don’t become part of your everyday diet.’
The alternative: Nichola Ludlam-Raine, a registered dietitian and author of How Not to Eat Ultra-Processed, suggests kombucha as a better swap.
It provides a fizzy hit with live cultures that may support the gut microbiome.
Energy drinks
Mr Hobson says energy drinks are ‘a perfect storm’ for gut health, thanks to their combination of caffeine, sweeteners, acidity and additives.
‘High caffeine intakes stimulate gut motility, which can worsen diarrhoea and cramping in sensitive individuals,’ he says.
‘And the sugar or sweetener content can disrupt the gut microbiome and increase bloating.
‘The acidity may also aggravate reflux and upper gut symptoms, particularly when drunk on an empty stomach.’
The alternative: Ms Ludlam-Raine recommends unsweetened tea or coffee, which contain polyphenols that may support gut bacteria diversity.
Black coffee can also be a better option than energy drinks – though too much can still cause digestive upset.
Protein shakes
Protein shakes can be convenient – but some are packed with ingredients that can upset digestion.
Artificial sweeteners, sugar alcohols and thickeners can trigger bloating, gas and diarrhoea in some people.
Ms Vidmar says: ‘Protein shakes can be useful, but many contain artificial sweeteners, emulsifiers and sugar alcohols that are poorly tolerated by the gut, causing bloating and other issues.
‘Whey protein can also cause bloating in people who are lactose-sensitive.’
The alternative: Choose a powder with minimal additives, and blend it with whole foods – or skip the shake and go food-first, with options like eggs, chicken or tofu.
Ms Ludlam-Raine adds: ‘Overall, the gut tends to thrive on simplicity and consistency: plenty of fluids, minimal added sugars, moderate alcohol, and a diet rich in whole foods rather than relying on functional drinks alone.
‘It’s important to avoid an overly black-and-white approach. An occasional fizzy drink or glass of alcohol isn’t likely to undo an otherwise balanced diet.’
