When to worry about flatulence – what is a normal amount to pass wind… and when could it be a sign of cancer

Breaking wind, letting rip or farting. For a bodily process we often don’t like to discuss, we have many words to describe it. 

Flatulence, as it’s known medically, is a subject that many people find far too embarrassing to talk about, even with their doctor.

According to medics, most people who complain about excessive gas do not actually produce more than average, they are just more aware of it. 

Indeed, flatulence is an entirely normal process which occurs around 15 to 20 times a day and is often the sign of a healthy gut.

It means gut bacteria are successfully breaking down food such as fibre that cannot be broken down elsewhere in the digestive tract.

The by-product of that process is wind — largely formed of carbon dioxide, hydrogen and methane. 

But there are times when flatulence may be a sign of something else more serious going on.

Smelly, excessive flatulence is often related to a dietary issue, however it can be a sign of another underlying concerning health issue.   

Why do some people have worse wind?

According to medics, the make-up of your gut microbiome — the community of microbes that live in your gut) — is a critical factor. 

This can change for a number of reasons, with common causes including diet and taking antibiotics. 

Food — and how it’s digested — can increase gas production.

For instance, as people age, they may have more trouble digesting foods that contain short-chain carbohydrates called FODMAPs, which stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. 

Common foods with gas-producing FODMAPs include broccoli, beans and lentils, wheat, garlic, onions, apples, and some fruit juices.   

Pharmacists also urge people to check the leaflet of any medicines taken, as wind, gas or bloating can be side-effects.

Metformin, a common diabetes medication and lactulose, a laxative are known to cause such symptoms.  

Equally, antacids such as magnesium carbonate or calcium carbonate can increase the amount of carbon dioxide produced in the stomach, triggering flatulence. 

Some are sold under brand names, including Gaviscon and Rennie.  

Poor diet 

Cannellini, kidney, white and pinto, the list of beans is long. 

Yet, while they are all different, they do have two things in common — high in fibre and a bad reputation for increasing flatulence. 

According to Dr Emily Leeming, a dietician and microbiome scientist, however, suffering a lack of fibre can lead to an unhealthy gut microbiome and more wind, not less. 

If the gut bacteria is less diverse, this can also cause more wind and bloating.

Fibre can also help with constipation, which causes smelly flatulence as food gets fermented for longer and traps gas. 

‘Just make sure to drink plenty of water too, as fibre can make constipation worse if you’re dehydrated,’ she says. 

‘When you start adding more fibre to your diet, be ready for a few days of extra wind, as when you start eating more fibre it’s like throwing your gut bacteria a birthday party — they joyfully binge on the fibre and produce a lot of gas.’

Another dietary culprit of pungent wind is eating too much red meat.  

This is due to a compound called sulphur — found in especially high levels in red meat.

Sulphur is also found in other meats and fish, eggs, cabbage, broccoli, brussels sprouts and cauliflower.

‘But it’s normally red meat that’s the culprit — as this is what we tend to eat too much of, rather than vegetables,’ she says. 

Lactose Intolerance 

If people often suffer excess flatulence after eating dairy such as milk, yoghurt or butter, lactose intolerance could be to blame. 

The intolerance occurs from not having enough of the enzyme lactase needed to break down lactose, the sugar in milk.

As a result it travels, undigested, through the gut where it is met by the bacteria that ferment it — resulting in a lot of gas. It can also lead to diarrhoea, constipation and nausea.

‘If you suspect this is the case you can try cutting down on dairy foods for a while to see if your symptoms improve,’ Dr Leeming says.

‘You won’t necessarily have to cut out dairy completely — usually the amount in a glass of milk can be tolerated each day, but this can vary.

‘Or you can choose lower lactose options such as kefir or hard cheeses.

‘You can also get lactase drops from the chemist (which you add to milk, for example) to help break down the lactose.’

Irritable Bowel Syndrome 

Equally, flatulence can be a problem for people with irritable bowel syndrome (IBS), the name for a collection of gut symptoms including constipation or loose bowels.

This can cause gut spasms and may lead to a painful build-up of wind.

IBS is one of the most common digestive conditions and is thought to affect around 4 in 100 people globally. 

According to the charity Guts UK, if people notice a particular food is constantly causing flatulence, alongside other symptoms such as painful cramps, constipation, diarrhoea or blood in the stools, it is vital to book a doctors appointment. 

Do not be tempted to self-diagnose. 

If a diet is suspected of causing symptoms, a GP can advise on simple diet changes, which may include a low FODMAP diet. 

Other flatulence relievers for those with IBS could include peppermint oil capsules, Dr Leeming also says. 

‘The menthol they contain helps relax the muscles of your gut and so release any wind. 

‘You can get the capsules from a pharmacy — though check with the pharmacist, as it’s not recommended when pregnant, or if you have liver disease or gallstones.

‘Peppermint tea can also be soothing, although won’t contain as much menthol.’

Bowel cancer

The presence of blood in stools, however, should never be ignored and may be a sign of something far more serious.

Experiencing both persistent flatulence and blood in the stools may be an indicator of bowel cancer.

Other symptoms of the condition often include changes in bowel movements such as consistent and new diarrhoea or constipation, needing or feeling the need to poo more or less frequently and bloating. 

‘If you’re experiencing other gut symptoms like consistent stomach ache or bloating, constipation, diarrhoea, unexplained weight loss or blood in your poo for three weeks or more, you should consult your GP,’ says Dr Johannes Uys, a doctor at Broadgate GP in London. 

GP Dr Amir Khan, who regularly appears on ITV’s Lorraine and Good Morning Britain, said that in some cases, the uncomfortable symptom — feeling fuller than usual, stomach pain and passing gas more frequently — can be ‘a red flag’. 

‘It is always worth getting this checked out, whether you have it as a single symptom or if its accompanied by other symptoms like weight loss, blood loss or a change in your bowel habits’, he adds. 

Ovarian Cancer  

Bowel cancer is not the only form of disease, however, that flatulence could be an indicator of. 

Although it is rarer, medics have repeatedly warned that women, particularly over 50, should be cautious of excessive bloating and persistent flatulence. 

Ovarian cancer often presents later, when it is harder to treat and one key issue women frequently describe is extreme bloating or flatulence. 

According to Ovarian Cancer Action this swelling is often caused by ‘ascites’ — a build-up of excess fluid in the membrane that lines the stomach wall and covers the organs inside the stomach. 

‘If you are experiencing these signs it is important to make an appointment to see your GP as soon as possible. 

‘Keep a record of your symptoms to take with you to your appointment, this will help to support you with your conversations with your GP and any other healthcare professional you may be referred to.’ 

Pancreatic insufficiency 

Equally, persistent flatulence may be an indicator of pancreatic insufficiency. 

The condition occurs when the pancreas doesn’t work properly and produce enough digestive enzymes to properly break down food.

Mild pancreatic insufficiency may not cause any symptoms at all or as mild abdominal discomfort, the NHS says. 

More moderate or severe pancreatic insufficiency, however, often results in bloating, cramps and increased flatulence.

Reasons behind the condition can include inflammation of the pancreas or even pancreatic cancer. 

Pancreatic enzymes are taken by mouth to compensate for the low levels produced by the organ because of the condition. 

This is known as Pancreatic Enzyme Replacement Therapy (PERT), and it is considered the standard treatment in the UK.

According to Guts UK, when taken properly PERT can improve fat, protein and carbohydrate absorption, reducing symptoms of the condition including flatulence and stomach pain.