Everyone farts. But not everyone tracks their farts. Now, smart underwear is making a case for paying closer attention to what comes out of your body. Its creators said they hope that tracking flatulence could eventually give researchers new insight into digestive health — and how a person’s farts offer clues about what’s happening in the gut. Brantley Hall, the brains behind the smart underwear and an associate professor at the University of Maryland’s department of cell biology and molecular genetics, said the team’s “ultimate mission is to help people eat high-fiber diets comfortably with low intestinal gas.” In the United States, it is estimated that 95 of Americans don’t eat enough fiber. The nutrient plays a critical role in digestive health, blood sugar and cholesterol regulation, and maintaining a healthy gut microbiome. (That’s the community of helpful bacteria and other microorganisms that live in your digestive system.) But for some people, eating more fiber also means more gas, especially at first. When you eat fiber, the gut microbes ferment it, resulting in production of gases such as hydrogen — and those gases eventually become farts. By studying who farts more, who farts less and how flatulence changes with diet, researchers aim to understand how microbes respond to different foods and why some people can tolerate high-fiber diets comfortably while others struggle with gas. The smart underwear is the first wearable designed to measure human flatulence. The measuring device is a small disc that snaps into the back of a person’s underwear. It then uses tiny electrochemical sensors to detect hydrogen, providing insight on the wearer’s flatulence. The results contribute to the Human Flatus Atlas, a research project that has recruited people around the world to wear the smart device while also documenting every meal they eat. While it is not a medical device, researchers said the technology could eventually have applications in medicine, including helping scientists identify early signs of gastrointestinal problems. Hall said the team hopes to help people “who show up at their doctor and say, ‘I feel bloated, or ‘I feel gassy,’ or ‘I feel abdominal pain.’“ By not just relying on people’s perceptions, but instead objectively measuring the production of farts, Hall said he and other researchers can do a better job understanding their digestive issues. Mindful about farts There is not a universal baseline of how many farts a day is normal, partly because it varies with each person. But that’s also because, before the smart underwear, there hasn’t been an efficient way to track farts. Doctors would either have to rely on a person to track their own farts or use a pretty invasive procedure to monitor them, Hall said. “There’s this guy; he’s named the King of Farts,” Hall said, referring to gastroenterologist Michael Levitt and his research. “He’s kind of like where all the fart studies came from, and he used a very embarrassing technique to measure farts. It was rectal tubes. It was like tube in the ass and counting farts as they came out.” The smart underwear, on the other hand, allows people to go about their days while simultaneously tracking their farts. It also can detect sleep flatulence, which is “a completely understudied or unstudied scientific topic. No one really knows how people are farting in their sleep,” Hall said. The Human Flatus Atlas has recently finished its second study of smart underwear users. In the first study, users were asked to wear the device for about 12 hours a day for seven days. In that paper, published in December in the scientific journal Biosensors and Bioelectronics, the researchers found that the average amount of farts was around 32 during that time period. For the new paper, which gathered data from more than 500 volunteers, subjects were asked to wear the device for at least 22 hours for anywhere between three to 30 days, only to take it off for activities such as showering and going to the bathroom. Hall said the team plans to release the new study soon. His hope is that, with the help of the smart underwear, doctors can one day better understand what’s happening in the gut and eventually identify patterns that could diagnose or monitor certain digestive conditions. Hall pointed to a 2023 study that looked at the digestion issues of nearly 89,000 Americans included in the National GI Survey II. The researchers found that about one in four had problems related to gas, whether that meant bloating, excessive gas or abdominal pain. Dr. Jordan Axelrad agreed that the smart underwear could one day “provide a continuous, non-invasive, real-world measure of microbial metabolic activity,” and could maybe even help researchers identify gastrointestinal problems before they fully develop. Axelrad, an associate professor at the New York University Grossman School of Medicine and co-director of the Inflammatory Bowel Disease Center at NYU Langone Health, was not involved with the Human Flatus Atlas project. For the most part, people don’t need to worry about the amount of gas they’re passing unless it is accompanied by other issues such as bloating, abdominal pain, diarrhea, constipation, weight loss, blood in the stool or a change in bowel habits, Axelrad said. “Passing gas is a normal and important part of digestive health,” Axelrad said in an email. “Most intestinal gas comes from bacteria in the colon fermenting carbohydrates that our bodies don’t completely digest, so the amount of gas we produce can vary considerably depending on what we eat, our gut microbiome, and even how much air we swallow with huge individual variation.” Dr. Trisha Pasricha, a physician-scientist at Beth Israel Deaconess Medical Center in Boston and assistant professor of medicine at Harvard Medical School, added that she often sees people in her clinic who suspect they have extra flatulence when actually they are within the normal range. “People often worry they fart more than average because we’re all so embarrassed about it — nobody’s counting how often they fart and sharing that number with their best friend,” said Pasricha, author of “You’ve Been Pooping All Wrong: How to Make Your Bowel Movements a Joy,” in an email. She also was not involved with the Human Flatus Atlas project. On the flip side, if someone notices that they haven’t passed gas at all and are having abdominal pain and no bowel movements, that’s a medical emergency that could represent a bowel obstruction, and they should seek care immediately, she said. “Right now, we have a lot of work left to do in understanding how changes in the gut microbiome truly connect to disease, and how changes we make to our diet can influence conditions that don’t even seem gut-related — things like cardiovascular disease or dementia, which can ultimately be shaped by our gut bacteria,” Pasricha said. With more research and data from studies such as the Human Flatus Atlas, she said we may get to the point of individualized microbiome-targeting therapies, such as personalized diets or probiotics. But there’s more work to be done before the connections can be made between specific microbes and disease. While researchers know that certain microbial species are more common in particular diseases, they don’t yet know whether those microbes are causing the problem or simply responding to an environment created by something else. “There isn’t good data showing that the number of farts alone signals something is wrong or points to a particular disease,” Pasricha said. “It can be a symptom of certain conditions — celiac disease or lactose intolerance, for example — but there’s no clear-cut correlation between disease and fart count, if you will. In fact, people often become gassier as they increase their fiber intake, especially at first, and that’s usually a good thing, not a warning sign.”
