Farting is totally natural and most of us do dozens a day. But it may be a little more if you’ve indulged over the Easter bank holiday, having chocolate, big lunches and hot cross buns.
While it’s easy to brush off a slightly stinky fart, when your wind suddenly becomes nuclear, it leaves you wondering what on Earth you have eaten that’s so offensive.
Funnily enough, science has found that we don’t mind the smell of our own trumps – while others disgust us due to an evolutionary survival instinct.
But even still, we can be left shocked by our own.
Adrienne Benjamin, a Gut Health Nutritionist at ProVen Biotics, says that “most intestinal gas is actually odourless”.
“The main gases we pass; nitrogen, hydrogen, carbon dioxide, methane and oxygen, don’t have a smell,” she tells Sun Health.
“The microbiota (gut bacteria) produce two to four litres of ‘gas’ every day, which can increase as we get older and our digestive capacity decreases along with our muscle control.
“Odour comes from trace gases produced when gut bacteria ferment undigested food, particularly sulphur-containing compounds such as hydrogen sulphide.”
It’s not the amount of gas that determines the smell, but the type of fermentation happening in your gut and the bacteria involved.
This bacteria forms part of your unique gut microbiome, a collection of trillions of different bacteria, some good and some bad.
This is why your farts may smell different to your friend’s or partner’s, despite eating the same foods.
The speed at which your food ferments and becomes farts varies between people.
“Factors include genetics, your hydration level, fibre intake, physical activity, stress levels, hormonal fluctuations and the balance of gut bacteria,” says Adrienne.
“Some people naturally have faster motility, so food moves through their digestive tract more quickly. Others have slower transit, which can increase fermentation time and sometimes lead to more gas build-up.”
Healthy adults fart an average of 32 times per day, according to scientists at the University of Maryland, which is double that reported by the NHS (five to 15).
The university made smart fart pants and trialled them on study participants. They found a spike in farts three to four hours after participants ate gum drops with tough fibre in.
If you’re experiencing a bad case of wind, you can use this guide to figure out the potential culprit…
EGGS AT BREAKFAST
It’s true that eggs can make your farts smell – and most people have these at breakfast time.
Eggs are rich in sulphur and “can increase the production of sulphur gases when they’re fermented by gut bacteria”, says Adrienne.
“Hydrogen sulphide is the compound largely responsible for the classic ‘rotten egg’ smell.”
The effect isn’t immediate, though.
Adreinne says it usually takes several hours, often six to 24 hours after eating the sulphur-rich food.
She says: “The food must travel to the large intestine where bacterial fermentation occurs. However, in people with faster gut transit or sensitivities, symptoms can appear sooner.”
LATTE ON ROUTE TO WORK
Milk, cheese, yoghurt, ice cream; these could also make your wind smell a little like rotten eggs, particularly if you’re lactose intolerant.
About five to 15 per cent of people in Europe are lactose-intolerant, according to the National Library of Medicine.
Adrienne says: “Lactose requires an enzyme called lactase to be properly digested in the small intestine.
“If lactase levels are low, lactose passes into the colon undigested, where bacteria ferment it, producing gas and drawing in water, which can also cause bloating and diarrhoea.
“In someone with lactose intolerance, symptoms can occur anywhere from 30 minutes to two hours after consuming dairy.”
If you’re concerned, visit your GP.
Adrienne says: “A doctor may suggest a hydrogen breath test, which measures hydrogen levels in the breath after consuming a lactose-containing drink.
“Elevated hydrogen can indicate malabsorption of lactose in the small intestine, as the lactose is then broken down by the gut bacteria in the large intestine, releasing hydrogen.”
You may also be asked to follow an elimination diet where you remove all lactose-containing foods, before slowly reintroducing them and tracking any symptoms.
SALAD AT LUNCH
If you favour a salad at lunch, those extra vegetables may make your gut go into overdrive.
Raw vegetables and ingredients like beans have high fermentable fibres. Although they’re healthy, as they feed your gut bacteria, in big doses, they can lead to gut-related issues.
Millicent Chapman, Nutritionist at Holland & Barrett, says: “Fibre is a nutrient in food that our body cannot fully break down.
“When fibre reaches the large bowel, the good bacteria that live there can ferment it.
“When they do this, they can make gas as a by-product. This gas can make you feel bloated or cause wind, and sometimes it can smell.”
That’s not to say you should stop eating vegetables!
But if you’ve suddenly ramped up your intake, and your gut is screaming, take it slower.
Gradually increasing your fibre intake allows your gut bacterial balance to change slowly, so it’s easier for you to tolerate.
Adrienne adds: “If someone suddenly increases their fibre intake, they may notice more bloating or smellier wind within 24 to 72 hours as the microbiome takes some time to adapt to the change.
“People who regularly eat high-fibre diets tend to have a more diverse microbial community that can process fibre efficiently, producing less uncomfortable gas and being able to more readily adapt to changes in fibre intake.”
Millicent says: “A little extra wind at first is normal, but don’t let it put you off, as 96 per cent of us in the UK still aren’t getting enough fibre, an essential part of a balanced diet.
“If you are eating more fibre, try to add it gradually and drink plenty of water. This can help your tummy get used to it.”
AFTERNOON SNACK BAR
When you’re hungry, it’s easy to grab something quick, like a packaged snack.
But, over half of the UK’s calorie intake comes from ultra processed foods, according to research published in the American Journal of Preventative Medicine.
Ultra-processed foods are foods that are packaged and have industrial ingredients in them, like added fats, sugars, additives and emulsifiers, and are no longer in a ‘raw’ state. Compare a chicken breast to a frozen, breaded chicken nugget, for example.
The sweeteners often used in ultra-processed foods could be behind your windy issues, Adrienne says.
Adrienne says: “Certain sweeteners, particularly sugar alcohols including sorbitol, xylitol and maltitol, are poorly absorbed in the small intestine.
“They reach the colon where they are fermented by gut bacteria, leading to gas production.”
Some artificial sweeteners may also alter the gut microbiome in ways that affect digestion.
“People with sensitive guts, irritable bowel syndrome (IBS) or existing bloating often notice increased wind after consuming products containing these ingredients,” Adrienne says.
STEAK FOR DINNER
If you can’t bear the smell of your stinkers in the evening, could it be the beef you had?
A high protein diet – meat, eggs and dairy – can cause stinkier wind than usual, so if you’ve recently upped your protein for weight loss or gym gains, it could be a plausible explanation.
Adrienne says red meat is among those pesky sulphur-rich foods – as well as garlic, onions and cruciferous vegetables (such as broccoli and cabbage).
Millicent says: “High protein diets can increase wind in some people.
“If protein is not fully digested and absorbed in the small intestine, some of it can reach the colon, where gut bacteria break it down.
“This process can produce gases, including hydrogen sulphide and other sulphur-containing compounds, which may contribute to odour.
“Changes in gas production can occur within a few days of increasing protein intake, although individual responses vary.”
WHEN TO WORRY
Although farting is normal and usually nothing to worry about, if your gas is also accompanied by persistent abdominal pain, unexplained weight loss, changes in bowel habits, blood in your poo, severe bloating or if symptoms are new and worsening, it’s worth visiting your GP.
“If symptoms are frequent or disruptive, it’s worth speaking to a GP to rule out conditions such as lactose intolerance, coeliac disease, IBS or other digestive disorders,” says Adrienne.
When your wind reveals a hidden health condition
Everyone farts – it’s normal! But there are times when fluffing goes beyond the expected amount and could be a sign of something serious.
IBS
IBS can be agonising, causing frequent tummy discomfort, bloating, constipation as well as bouts of diarrhoea.
Another symptom of IBS is frequent gas.
IBS can also lead to other complications such as a lack of energy, feeling sick or nauseous, pain during sex and social anxiety and depression.
So if you think you might have the condition speak to a GP.
Coeliac disease
Coeliac disease is an autoimmune digestive condition where the intestines react to gluten and become inflamed.
The adverse reaction can come from the dietary protein which is often found in three cereals: wheat, barley and rye.
The gluten damages the lining of the intestines making the body unable to absorb important nutrients.
Coeliac disease is a life-long condition that can lead to bloating, nausea, excess gas and tiredness, and is only treated by a change in diet.
Bowel cancer
It’s unlikely your wind is bowel cancer, also known as colon cancer or colorectal cancer, which is the fourth most common form of the disease in the UK.
But the key red flag signs for the disease include blood in your poo, tummy pain, bloating and a change in bowel movements.
A side effect your bowel movements changing can be gas, so if you are farting a lot and notice other symptoms speak to a GP.
