The ultimate guide to keeping a healthy gut - and the symptoms experts say you must NEVER ignore

Plagued by stomach cramps, constipation or acid reflux? Do certain foods trigger bloating and gas or prompt an emergency dash to the loo?

You're not alone. Gut symptoms account for one in eight GP visits.

And gut-related problems are rising. Cases of inflammatory bowel disease (autoimmune conditions such as Crohn's disease) shot up by 34 per cent in ten years, reported BMC Gastroenterology.

Surveys show as many as one in two people have acid reflux; food intolerances are also on the rise.

So why is this happening? Our changing diets – eating more highly processed foods, for instance – and our expanding waistlines are partly to blame.

As Dr Simon Smale, a consultant gastroenterologist at Manchester Royal Infirmary, explains: 'Some processed foods, such as ready meals containing complex carbohydrates, can increase symptoms such as bloating because they're harder to digest. Sensitivity hasn't gone up – it's that people are eating more of them.'

'Reflux is also more common and that may reflect the type of foods people are eating and the increase in weight, too.'

Changes in diet may help explain the rise in bowel cancer cases in younger people. This includes eating more processed foods, red meat and cured meats containing nitrates, says Dr Ana Wilson, a consultant gastroenterologist at St Mark's Hospital and the private One Welbeck, in London.

Common treatments such as acid reflux drugs called proton pump inhibitors (PPIs) are also implicated. 'They are good drugs if used in the right people for the right amount of time, but they've been taken like Smarties – and we know PPIs change the gut microbiome,' says Nick Boyle, a consultant gastrointestinal surgeon at the private clinic Reflux UK.

Today, in the latest in our series on common ailments, we've joined forces with leading experts in this guide to beat gut trouble based on the scientific evidence.

So what's your gut trying to tell you?

Symptoms such as bloating, wind, diarrhoea, tummy pain and constipation can have a number of causes, from the foods you eat, to hormones or infections. Usually it's a short-term problem, but it can also be a sign of an underlying issue. Here is the expert lowdown on what might be causing your gut symptoms...

Symptoms: A burning sensation in your chest; sour taste in your mouth; bloating; nausea; hoarse voice and dry cough that's worse at night.

It could be: Acid reflux. This affects 40 per cent of us at some point. Stomach acid travels back up the oesophagus (or gullet). It's often caused by weakness in the valve that should stop stomach contents moving upwards.

Chronic acid reflux is known as gastro-oesophageal reflux disease (GORD).

Triggers include being overweight, pregnancy and smoking (all can cause the valve to relax); non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen (they block enzymes that protect the stomach lining); and stress and anxiety (which can increase stomach acid production). Over time, GORD can lead to Barrett's oesophagus, where the cells lining the gullet are damaged – this is a risk factor for oesophageal cancer.

Around 150,000 Britons have been diagnosed with this condition, but 500,000 are estimated to be undiagnosed.

How it's diagnosed: See your doctor if your acid reflux lasts longer than three weeks, says Dr Smale. Barrett's is traditionally diagnosed with an endoscopy, where a camera on a long, thin tube is passed down your throat to check for signs of cell changes.

Newer, minimally invasive tests – Cytosponge or Endosign – are sometimes available on the NHS. These capsules (which you swallow) contain a sponge, attached to a string, that collects cells from the oesophagus lining.

TREATMENTS

LIFESTYLE: Carrying excess weight – particularly around your middle – increases gastric pressure, causing acid to rise into the oesphagus: losing weight will help.

Check your diet: Fatty foods release a hormone that relaxes the valve at the lower end of the oesophagus, while acidic foods such as orange juice, tomatoes, and alcohol, can irritate the valve. Fizzy drinks fill the stomach with gas, increasing pressure.

Dr Smale advises eating 'smaller meals throughout the day rather than one big meal in the evening', and tackling stress.

DRUGS: Over-the-counter antacids (e.g. Gaviscon) 'float on top of the acid, acting as a physical barrier' to prevent it rising up. Prescription drugs include PPIs (e.g. omeprazole and lansoprazole), reduce stomach acid production.

Although they're effective for 80-90 per cent of people, they can have side-effects, such as diarrhoea and constipation.

Research also suggests that long-term use of PPIs can increase the risk of C.diff infection, pneumonia and Covid-19, because of changes to the gut microbiome.

If PPIs don't work after two weeks, you may be offered an H2 receptor antagonist (e.g. famotidine) which blocks a receptor in the stomach responsible for releasing acid.

SURGERY: If lifestyle changes and drug treatments don't work, surgery is an option.

Procedures include a fundoplication, where the top of the stomach is 'wrapped' around the bottom of the oesophagus, supporting the valve. Available on the NHS, it costs around £7,000 privately.

Newer treatments include LINX, where a small band of magnetic titanium beads is placed, via keyhole surgery, around the valve to keep it shut. The pressure of food pushes the beads apart; the magnetic force between the beads then draws them back together. Risks include difficulty swallowing for a week. LINX is available on the NHS; it costs around £11,000 privately.

A newer surgical procedure, transoral incisionless fundoplication, involves inserting a surgical instrument via the mouth to twist the top of the stomach around the bottom of the oesophagus – the two are then stapled together to support the valve.

Studies show 75 per cent of patients stopped or reduced taking PPIs within five years of the treatment. Rare complications include bleeding, stomach injury, infection and oesophageal perforation.

This procedure is available on the NHS at some centres; it costs £14,000 privately.

Symptoms: Abdominal pain; a change in bowel habit (diarrhoea or constipation); bloating. Also tiredness, wind, concentration problems and backache.

It could be: Irritable bowel syndrome (IBS). The condition, which affects an estimated ten million Britons, is a collection of persistent bowel symptoms. It's possible to have constipation as your main symptom or diarrhoea, or a mixture of both.

Women tend to suffer more from constipation, particularly in the first 12 days of their menstrual cycle, as high levels of oestrogen and progesterone can slow gut movement.

How it's diagnosed: There is no test for IBS. If you've had persistent gut symptoms for six months or more, your GP will want to rule out conditions such as coeliac disease.

TREATMENTS

LIFESTYLE: Simple lifestyle changes – such as eating regular, small meals – can make a massive difference, says Dr Smale. So, too, can limiting caffeinated drinks to three a day (caffeine stimulates the bowel, leading to loose stools). Many experts recommend the low-FODMAP diet (see box).

High-fibre drinks such as Fybogel can help with constipation. You could also try probiotics, though the NHS says stop if you don't see results after four weeks.

Parallel is a three-month online CBT programme, prescribed on the NHS, to help patients learn how altering behaviour and emotional responses affects the gut to take control of their symptoms.

Patients who received this kind of CBT were more likely to experience significant improvements in symptoms and quality of life than those on standard treatment, reported researchers at King's College London in 2019.

Another option is Nerva, developed at Monash University in Australia, which uses hypnotherapy techniques to reduce stress and anxiety, which directly impacts IBS symptoms (cost £149 a year).

MEDICATION: Over-the-counter treatments include laxatives for constipation, and anti-motility drugs (e.g. loperamide) if you have diarrhoea.

'It's fine to take these intermittently if your symptoms come and go, but if they are new symptoms that persist you need to see a doctor,' says Professor Peter Whorwell, a consultant gastroenterologist at the University Hospital of South Manchester.

Buscopan (available over-the-counter) is recommended for IBS cramp: it reduces muscle contractions in the gut and bladder.

A study by Newcastle University found Enterosgel IBS Relief (£14.50, Boots) reduced gut pain better than a placebo. It 'captures' harmful substances that cause diarrhoea.

Symptoms: Diarrhoea, weight loss and tummy pain. Also wind; constipation; nausea; fatigue; anaemia; bloating; an itchy rash; loss of tooth enamel; numbness/tingling in hands and feet.

It could be: Coeliac disease or non-coeliac gluten sensitivity (NCGS) – with the latter, symptoms occur soon after eating gluten.

Coeliac disease is an auto-immune condition where the immune system mistakenly attacks its own tissues when you eat gluten (found in wheat, barley and rye).

This damages the gut lining and means the body can't properly absorb nutrients from food, which can lead to nutritional deficiencies.

People with NCGS react to gluten but their gut lining is not attacked.

There's been an increase in coeliac disease's prevalence, but only a third of cases are diagnosed, says gastroenterologist Professor David Sanders, chair of Coeliac UK's Health Advisory Board.

He says the varied nature of symptoms makes it difficult to identify a cause and it can take years to get a diagnosis.

How it's diagnosed: Your GP can order a coeliac disease antibody test (you need to have eaten at least one meal containing gluten a day for at least six weeks beforehand). A positive result is confirmed with a gut biopsy.

If coeliac disease has been ruled out, 'we suggest patients follow a gluten-free diet to see if symptoms improve', says Professor Sanders.

TREATMENT: If diagnosis is confirmed, symptoms will disappear on a gluten-free diet. Although some gluten-free foods are available free on prescription, it's a postcode lottery.

Symptoms: Frequent bouts of watery diarrhoea; faecal incontinence with cramps; flatulence and smelly wind.

It could be: Bile acid diarrhoea (BAD). This is caused by an overproduction of bile acid salts (which digest fats), or the bile salts not being recycled properly by the small intestine. If this excess salt passes into the large intestine, it stimulates water to be secreted, leading to watery diarrhoea.

As many as one in three IBS patients with diarrhoea as the main symptom may actually have BAD, but few have heard of it, says Professor Julian Walters, a consultant gastroenterologist at Imperial College Healthcare NHS Trust.

'This matters because there is a test and specific treatment for BAD – unlike other causes of IBS,' he says.

How it's diagnosed: SeHCAT is a test available at some specialist centres that measures how well your body absorbs bile salts. It's not approved for NHS use; privately it costs £1,000.

TREATMENT: Prescription medication includes bile acid sequestrants, which contains a resin that binds to the bile acid salts, forming an insoluble compound excreted in faeces – for example, cholestyramine (brand name Questran) and colesevelam (Cholestagel) tablets. The side-effects can include bloating, pain, nausea and constipation.

Symptoms: Diarrhoea lasting longer than four weeks; colicky tummy pain; clear slime in poo; bleeding from bottom; feeling tired all the time; mouth ulcers and losing weight without trying.

It could be: Inflammatory bowel disease (IBD).

IBD is an umbrella term for conditions where the immune system attacks bowel tissue, causing inflammation and sores. Symptoms can flare-up and then go into remission.

The main types of IBD are Crohn's disease, which affects the length of the gut; and ulcerative colitis, which affects the large intestine.

Half a million people in the UK have IBD.

How it is diagnosed: Tests for IBD include blood tests for C-reactive protein (CRP) and sedimentation rate, which detect inflammation in the body.

If IBD is suspected, you may be referred for a colonoscopy (where a tiny camera is inserted to check for inflammation) plus a biopsy to check for abnormal cells, as well as scans.

TREATMENT: Medication aims to put patients into remission by reducing inflammation.

Drugs include steroids such as prednisolone and budesonide, and biologics such as adalimumab – given by injection every two weeks, these target proteins that cause inflammation.

Newer tablets, JAK inhibitors, block the activity of enzymes involved in inflammation.

Symptoms: Bloating; discomfort after eating carb-rich foods; abdominal pain; excessive belching; reflux; flatulence; plus diarrhoea and fatty stools, or constipation.

It could be: Small intestinal bacterial overgrowth (SIBO). This is caused by bacteria multiplying in the small intestine, leading to fermentation of food and gas. Professor Peter Whorwell says 5 to 10 per cent of people with IBS have SIBO.

How it's diagnosed: This involves a breath test for hydrogen or methane after drinking a glucose drink – a rapid rise in both gases can indicate SIBO. The test is available on the NHS.

TREATMENT: The standard treatment is a two-week course of specific antibiotics.

Red flags to watch

Most gut symptoms are not a sign of something sinister. But there are some red flags that need medical attention. These include:

● New gastrointestinal symptoms for more than three months in someone over 50.

● Persistent bloating, abdominal pain, abnormal or post-menopausal bleeding.

● Bleeding from the bottom or blood in your poo. ‘In 95 per cent of cases this is due to something benign such as haemorrhoids, but your GP should arrange a stool sample test,’ says gastroenterologist Dr Ana Wilson. Alongside symptoms such as persistent and unexplained weight loss and change in bowel habits – feeling tired all the time for no obvious reason or a pain or lump in your tummy – all could be signs of bowel cancer.

● Indigestion or heartburn for more than three months.

Are you a victim of secret gut saboteurs?

Too much fibre & veg

We’re urged to eat a diet high in fibre (found in bran, wholegrains, fruit and veg) for bowel health. But it may not help if you have IBS – or your gut is sensitive.

Gastroenterologist Professor Peter Whorwell says he often has to tell his IBS patients to ease up on healthy fibre-rich foods such as green veg and bran, eating ‘less healthily, rather than unhealthily’, he makes pains to clarify – ‘and definitely not filling up on junk and processed food’.

Research he led found that 50 per cent of IBS patients’ symptoms worsened when they ate bran, which had long been the default treatment for IBS: ‘Their sensitive gut couldn’t handle it,’ he says.

Meanwhile, 15 to 30 per cent of people with constipation suffer with ‘slow-transit constipation’ – where their gut doesn’t propel food fast enough: too much fibre compounds the problem.

‘People have been bombarded with the messaging about five-a-day – the trouble is they now think it would be even more healthy to eat seven or eight, which might be too much for their particular gut,’ says Professor Whorwell, adding it’s fine for people with normal gut function.

‘If you suspect that this is you, try cutting out some veg and see if it makes a difference,’ he says.

Antibiotics in childhood

‘Antibiotic use in childhood is a major cause of IBS – they seem to mess it up for good,’ says Professor Whorwell. ‘Adolescents also get given long-term antibiotics for acne and this can affect the gut microbiome.

‘Non-steroidal anti-inflammatory drugs (such as ibuprofen) are also bad for the gut – rheumatologists love them but gastroenterologists hate them.’

They can destroy the good gut bacteria.

Big dinner plates

Feeling bloated could simply be a sign that you’re eating too much.

‘So many people complain about feeling bloated, but it is sometimes just because portion sizes are too big, says Dr Adrian Barnardo, a consultant gastroenterologist at the Benenden Hospital in Kent. Average plate sizes have doubled since the 1960s, he adds.

‘You can get around 800 calories on an 8 ½in plate and 1,900 on a 12in one – that’s a lot more calories to digest in one go.

‘We’re also eating most of our calories in a main meal in the evening before bed – it’s better to eat smaller meals spread through the day,’ he says.

Alcohol to 'settle' tummy

‘Contrary to popular myth, a brandy or a sherry won’t settle your stomach directly – though it may soothe your anxiety and that may indirectly calm your stomach,’ says Professor Whorwell. Alcohol is generally ‘a poison to the gut, except at low doses’. It damages the gut lining, adds gastroenterologist Dr Simon Smale. ‘It also relaxes the oesophageal valve, increasing the risk of acid reflux.’

If consumed in high quantities, alcohol can result in diarrhoea. Professor Whorwell explains: ‘I used to treat a lot

of alcoholics and they were never constipated, they all had diarrhoea.’

Coffee, tea and fizzy drinks

Caffeinated drinks have gut health benefits – for instance, research this year by Wageningen University in the Netherlands found that more than four cups of coffee a day significantly lowered the risk of bowel cancer recurrence.

But more than three caffeinated drinks a day can make IBS worse, says Dr Smale. ‘It can increase gut motility [movement of food] and make you more likely to have diarrhoea.’

Fizzy diet drinks may also be bad news, he says. ‘The gases will fill up the stomach, causing reflux and bloating – and sorbitol [a sweetener] can ferment, causing bloating and diarrhoea.’

Eating on the hoof

Rushing eating can cause bloating and wind, as you swallow too much air, says dietitian Lucy Jones. Before you assume it’s a gut issue, consider whether you’re eating too quickly, she suggests.

‘Chew properly, with a little pause and put your knife and fork down between mouthfuls.’

Blame prescription pills - or Ozempic

● Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, aspirin and (prescription-only) naproxen can cause constipation, gas, bloating and heartburn and can irritate the lining of the stomach. Also, they reduce chemicals called prostaglandins that cause inflammation – but that also protect the gut lining. A doctor can prescribe proton pump inhibitors (PPIs) such as omeprazole to protect against these side-effects.

● Opioid painkillers such as codeine can cause constipation, slowing down muscle movement in the digestive tract.

● Antibiotics wipe ‘good’ gut bacteria as well as bad. Probiotic supplements may prevent diarrhoea if taken at the same time, says the British Dietetic Association.

● Ozempic or Wegovy can cause gastric side-effects - the main reason people quit these weight-loss drugs. The most common are nausea and diarrhoea. Others may include stomach pain, heartburn, gas and bloating. These should settle down after a few weeks.

● PPIs prescribed for acid reflux can cause diarrhoea and constipation.

● Iron tablets can cause constipation, possibly by altering the gut microbes.

What's behind smelly wind?

‘A significant proportion of the population may have an intolerance to lactose, the sugar in dairy products,’ says dietitian Lucy Jones. This includes people with African or Caribbean heritage, or from Asia, as they may not produce enough lactase, an enzyme needed to digest lactose.

We also produce less lactase with age – ‘older people may be able to tolerate a little blob of butter but not a milkshake for instance,’ she says. You can develop a temporary lactose intolerance after a tummy bug.

Undigested, lactose ends up in the colon – fermenting and producing a smelly gas. Other symptoms include tummy pain or discomfort after eating dairy: followed by bloating, diarrhoea and constipation, nausea and vomiting. 

Longer-term symptoms include joint pain and fatigue. To confirm a diagnosis, the charity Allergy UK suggests not eating foods with lactose for two weeks, then gradually reintroducing the foods to see which are problematic.

Another cause of smelly wind is bile acid diarrhoea (BAD).

If food gets stuck in your throat...

Difficulty swallowing, chest pain and heartburn that doesn’t respond to medication can point to eosinophilic oesophagitis (EoE), a type of food allergy. It’s the most common reason for adults going to A&E with food stuck in their throat.

Typically it affects people with other allergies such as hay fever and asthma, and cases are rising. ‘It’s an allergic reaction to certain foods, usually dairy, wheat, eggs, nuts, soy and shellfish,’ says Dr Jamal Hayat, a consultant gastroenterologist St George’s University Hospital in London.

This reaction leads to a build-up of eosinophils (white blood cells) in the oesophagus lining, triggering inflammation and swelling.

To find the trigger food is a process of trial and error (see eosnetwork.org). The steroid budesonide (brand name Jorveza) ‘is a highly effective treatment’, says Dr Hayat.

Bunged up? Eat sweetcorn to check your transit time 

Food takes on average 53 hours to pass from your mouth to the anus. A simple test for your gut transit speed is to see how long it takes for sweetcorn to appear in your poo.

Food is propelled along by automatic, wave-like contractions of muscles in the gut.

Mouth and oesophagus (or gullet)

Food can spend as little as a few seconds to a few minutes in the mouth. It then transits down the oesophagus and within seconds is

in the stomach, explains Dr Nik Kamperidis, a consultant gastroenterologist at St Mark’s Hospital and HCA Princess Grace Hospital, both in London.

Stomach

Here the food is mixed with gastric juices, produced by cells lining the gut. Non-fatty foods will pass through in about one to two hours; fatty meals such as burger and chips take between two and four hours, which is why a meal with these can leave your stomach feeling full for longer.

The speed also depends on underlying conditions such as diabetes and Parkinson’s, which can delay the speed at which the stomach empties and slow down gut transit generally.

Medication (see previous page) can have the same effect. And the more food you eat in a meal, the longer it will take.

Small intestine

By the time food gets here, it will mostly be mush (apart from sweetcorn and some high-fibre foods). This is where food is broken down into nutrients to be absorbed by cells lining the small intestine wall. This stage takes two to six hours.

Large intestine (or colon)

‘Whatever is left over – usually fibre and water – is moved down to the large intestine, where excess water is reabsorbed and undigested food becomes faeces, which is then moved to the rectum,’ says Dr Kamperidis. This stage can take anywhere between ten and 59 hours.

Rectum

‘People worry about not having a daily bowel movement but anything from three times a day to three times a week is considered to be in the normal range,’ says Dr Kamperidis.

Constipation is more common with age: ‘Everything in the body becomes more sluggish.’

‘Whatever your age, making time to have a bowel movement is important because you can lose the urge to pass one if you think you don’t have time,’ says Dr Kamperidis. ‘Some people don’t want to have a bowel movement at work, for instance.’ This can lead to constipation.

Be sure to check your technique

‘Sit with your feet on a stool, so your knees are above your hips: this ensures your rectum is at the right angle, so the muscle responsible for passing stools relaxes and the colon straightens, making it easier for it to exit.’

Try gut massage for constipation. Start on the right lower side of your abdomen, with gentle pressure stroke upwards towards your ribs, then across, then down the right side (this follows the direction of your bowel).

Constipation that’s lasted more than two to three weeks should be checked, especially if it’s a new symptom, you’re over 50 and have a family history of bowel cancer, says Dr Kamperidis.

Should you switch to a gut-kind diet?

No single, specific food will always cause bloating in everyone – ‘everyone’s gut and how it reacts to different foods is individualised,’ says dietitian Lucy Jones.

‘So if you think certain foods make you more windy, it’s best to have a trial and error approach to find out how much of a food you can tolerate – it’s not like having an allergy where you have to avoid some foods.’

For people with ibs, the advice may be to try the low-FODMAP diet. FODMAPs are sugars found in many foods – including wheat, rye, onion, garlic, legumes (beans, chickpeas and lentils), apples, stone fruits, milk, honey – and as sorbitol in sugar-free mints.

The FODMAP sugars are not properly broken down until they reach the colon, where they are fermented by bacteria, creating gas and causing bloating and pain.

Studies show that a low-FODMAP diet can improve IBS symptoms in around three-quarters of those who try it.

It was designed as a short-term diet to ‘reset’ the gut to see if it improves symptoms, and then reintroducing FODMAP foods gradually to see which trigger symptoms, explains Dr Ana Wilson, a consultant gastroenterologist at St Mark’s Hospital in London.

‘You’re meant to exclude FODMAP foods for six to eight weeks. This is best done under the supervision of a dietitian,’ she says. Without supervision, ‘what can sometimes happen is people cut out the FODMAPs, find their symptoms improve and end up on a very restrictive diet where they are eating a narrow range of foods’. This can then lead to nutritional deficiencies.

When probiotics are the solution for your symptoms

Gut symptoms are often directly related to the gut microbiome – the community of bacteria, viruses and fungi – as anyone who’s had a bout of diarrhoea after a course of antibiotics (which wipe out the ‘good’ bacteria, too) will know.

An imbalance of gut bacteria has been linked to gut conditions such as IBS. So will a probiotic help?

Gastroenterologist Professor Peter Whorwell tells his IBS patients that probiotics won’t do them any harm: ‘If they don’t work after four weeks give them up.’ 

But finding the right product can be tricky, as Dr Emily Leeming, a dietitian and microbiome scientist at King’s College London, explains: ‘It’s like the Wild West at the moment, with companies adding health claims to probiotic products that are for the added ingredients, such as calcium.’

A good rule of thumb is to choose products with at least one billion CFUs (colony-forming units of bacteria), says Aidan Goggins, a pharmacist and an independent advisor to supplement makers. ‘A blend of different bacteria strains isn’t more effective than a single strain – but check the strain has been studied independently and shown to be beneficial for a specific purpose.’ (e.g. Limosilactobacillus reuteri has been shown to ease diarrhoea.)

He adds: ‘Probiotics are sensitive to damage in the manufacturing process, such as heat, so opt for free-flowing powders or capsules rather than gummies and pressed tablets.

‘Also, the manufacturing of more heavily processed products such as gummies and pressed tablets may have exposed the “good” bacteria to conditions that reduce their overall effectiveness.’ And bear in mind that their beneficial effects are short-lived unless consumed regularly, he adds.

‘So to maintain any gut health benefits, you need to make probiotics a consistent part of your daily routine.

‘Take them at least half an hour before meals when stomach acid is at its lowest, and avoid having them with hot drinks, juices or alcohol as these can degrade the beneficial bacteria.’

But if you’re well and healthy, Emily Leeming says your money ‘would be better spent on feeding your gut bacteria with fibre-rich foods – even one apple has 100 million microbes and they’ll make their way to the gut.’