It’s often seen as a taboo subject, but a new study is finally lifting this lid on humans’ farting habits.
Scientists from the University of Maryland have developed ‘smart underwear’ that records exactly how often someone passes wind.
According to the first study using this bizarre device, people fart twice as often as scientists previously thought.
The average person lets one go 32 times a day, compared to the 14 that doctors once considered normal.
However, the researchers also found significant variation between different ends of the flatus spectrum.
At the extreme end are the so–called ‘Hydrogen Hyperproducers’, whose unique guts produce 40 to 50 farts per day.
The ‘Zen Digesters’, meanwhile, have the enviable ability to eat a high fibre diet while their digestive tract remains unusually silent.
Despite eating 25 to 38 grams of fibre per day, Zen Digesters might produce as few as four daily farts.
Scientists have developed a ‘smart underwear’ sensor that tracks how often people fart, and it reveals that the average person breaks wind 32 times per day
There is a big difference between the most active ‘Hydrogen Hyperproducers’, who might fart 40 to 50 times a day, and so–called ‘Zen Digesters’, who break wind as little as four times a day
The smart underwear device is a small, coin–sized gadget that clips into a normal pair of pants.
Using a small electrochemical sensor, the device keeps a constant record of the hydrogen and other gases emitted by your gut.
Since hydrogen is exclusively produced by microbes, tracking this gas provides a direct readout of when and how intensely the gut microbiome is active.
While it might seem silly to focus so much on human flatus, this research actually fills a surprising gap in our medical knowledge.
When doctors look at a patient’s condition, they compare certain markers to a generally agreed–upon average known as a baseline.
Baselines exist for things like heart rate, cholesterol and blood glucose, but scientists haven’t been able to find a baseline for farting.
Lead author Dr Brantley Hall, a gut biome expert from the University of Maryland, says: ‘We don’t actually know what normal flatus production looks like.’
Previous attempts to find the average have typically relied on people reporting their own flatulence throughout the day.
Going forward, the researchers plan to expand their study and send smart underwear to as many people as possible for a research programme dubbed the Human Flatus Atlas
However, people have unreliable memories and can’t keep track of what is happening while they sleep.
To make matters more difficult, people have differing levels of ‘visceral sensitivity’, meaning someone might produce more flatus and simply not notice.
The alternatives are short–term, highly invasive tests conducted in the lab, such as those that use rectal tubes to collect gas samples.
As a result, doctors had considered it largely impossible to provide any objective measurement of whether someone really had excess gas.
By contrast, the smart underwear device is small, easy to use, and barely noticeable throughout the day.
In their trial, over 80 per cent of participants said that the device was comfortable and that they would be happy to wear it if advised to by a doctor.
This has allowed researchers to get the first accurate, real–time measurements of how much flatulence people really produce.
Dr Hall says: ‘Objective measurement gives us an opportunity to increase scientific rigor in an area that’s been difficult to study.
The researchers say that their smart underwear (pictured) fills a vital gap in our medical knowledge by revealing the ‘baseline’ for normal amounts of flatulence
‘Without that baseline, it’s hard to know when someone’s gas production is truly excessive.’
Besides telling scientists when someone is above that baseline, this research also helps scientists understand what is happening inside our guts.
In the study, participants were asked to eat sweets containing a small amount of inulin, a type of prebiotic fibre.
The smart underwear device successfully detected the increased hydrogen production triggered by the resulting digestion with 94.7 per cent accuracy.
‘Think of it like a continuous glucose monitor, but for intestinal gas,’ says Dr Hall.
In their initial trial, the researchers recruited 19 adults to wear the device for a week during waking hours.
However, the team are now expanding the study into a nationwide research programme dubbed the ‘Human Flatus Atlas’.
Anyone over 18 and living in the US can enrol in the study, and Dr Hall will send them a smart underwear device to start recording their own fart data.
The researchers are particularly interested in Zen Digesters and Hydrogen Hyperproducers, which both have gut responses far outside the average range.
The team will also collect stool samples from participants in these groups for microbiome analysis, so that they can learn why these people fart so much or so little.
Dr Hall says: ‘We’ve learned a tremendous amount about which microbes live in the gut, but less about what they’re actually doing at any given moment.
‘The Human Flatus Atlas will establish objective baselines for gut microbial fermentation, which is essential groundwork for evaluating how dietary, probiotic or prebiotic interventions change microbiome activity.’
