America’s Gut Doctors Met in Nashville for ACG 2026. Here’s What They Found

Exhibit Halls A through D sit on the third level of Nashville’s Music City Center, a few blocks from the neon on Lower Broadway, and this week they hold the meeting’s poster sessions, where research on the colon, the liver, the stomach and everything in between is presented by the doctors who did the work. It is ACG 2026, the annual meeting of the American College of Gastroenterology, and it runs through Wednesday. On Sunday at noon Central, when the meeting’s embargo lifted, the college flagged 20 of its studies as the ones the public should hear about. We read all 20, along with what most of their authors wrote about what the work means for patients, and kept the ones that change something for an ordinary gut. Here they are, with the number, the catch and who should care.

Long races: Hospital records link marathons and ultras to colon injury, and the longer the race, the stronger the link

The meeting opened on a big weekend for endurance sport. On Saturday at the Ironman World Championship in Kona, Taylor Knibb walked through an aid station, vomited, kept going past a whiteboard on which her manager had written “vomiting is normal,” and won, NBC Sports reported. On Sunday, Chicago ran its marathon. Cramping, diarrhea and, occasionally, bleeding are common in endurance athletes, the lead author of poster P0294 writes. The question the team asked is how often that tips over into a diagnosable injury to the colon.

For their ACG 2026 poster, Uwakmfonabasi Umoudoh and four colleagues took five years of national in-hospital records and compared adults with documented endurance activity against similar patients. Ischemic colitis, an injury to the colon caused by reduced blood flow, was diagnosed in 5.5 percent of the endurance group and 2.0 percent of the comparison group, close to three times the odds. The finding the author points to is the gradient: ultra-distance runners and cyclists carried roughly double the risk of half-marathoners. That is the pattern you would expect if the cause is the body sending blood away from the gut toward the muscles and heart during a long effort, which experiments have measured directly. The endurance group also had more ICU admissions, kidney injury and sepsis, which the author reads as the colon being one sign of a whole body under strain.

The catch, in the author’s own framing, is that this is “a signal, not a verdict.” Everyone in the data was already in a hospital; the study says nothing about runners in general, and the activity codes it relied on are optional and under-used. Nothing in it says endurance exercise is dangerous or that anyone should train less. What Umoudoh does say, in the note for patients, is that bloody stool, severe belly pain or cramping that keeps going well after the finish is not part of a hard race, and that telling the doctor you just ran or rode a long event changes what they look for. Our marathon poop explainer, the Hyrox bathroom rule and the Chicago gel piece cover the everyday version of the same physiology.

Under 50: Colon cancer in young adults is still rising in the US. Worldwide, fewer of them are dying from it

Two ACG 2026 posters, read together, give the whole picture. The first, P5002, used the national cancer registry known as SEER for 2000 to 2023. Its authors report an 89 percent increase over those 23 years in colorectal cancer diagnosed before 50, a yearly rise that sped up to nearly 10 percent between 2021 and 2023, increases in every racial and ethnic group with the steepest recent climbs among Hispanic and Black adults, and a pattern in which people under 50 are more often diagnosed after the cancer has already spread. The second, P2540, looked at the whole world from 1990 to 2023 and found the same direction for new cases among 30- to 44-year-olds, with the biggest increase at 40 to 44, and one line the US numbers don’t carry: death rates in young adults are falling, which the authors credit to better treatment.

“We want young adults to be aware, not anxious,” writes Ahmed Abdulelah, one of the global study’s authors. One caveat is ours, not the authors’: 2020 was the year the pandemic interrupted routine care, and the years right after a dip can include diagnoses that were delayed, so the 2021 to 2023 speed-up is the number we most want to see in the full paper. Routine screening for people at average risk starts at 45 under the US Preventive Services Task Force recommendation of 2021, and both posters ask whether that is early enough. Both sets of authors land on the same point for anyone younger: rectal bleeding or a lasting change in bowel habits is worth raising with a doctor at any age. Our guide to blood in stool covers what the colors mean.

AI: Ask a chatbot about a gut emergency in Vietnamese, and it misses the emergency far more often

This is the one to send to the group chat. In oral presentation 62 at ACG 2026, researchers gave four AI chatbots the same gut-emergency scenarios in the seven most common languages spoken in the US and checked whether each one told the person to get emergency care. In English, the chatbots failed to do that 15 percent of the time. In Vietnamese, about 41 percent. The scenarios were simulated, not real patients, and the summary does not name the four models. The errors were not only in other languages; English had them too.

The study’s point for patients is that a fluent answer and a reliable one are not the same thing. Its authors say AI can help explain information or prepare questions for a doctor, but should not be the thing that decides whether worrying symptoms can wait, and that it helps to tell the care team what the chatbot said. If you have a parent who asks their phone about a stomach pain in their own language, this is the study for them.

TikTok: Misleading gut TikToks get more engagement than careful ones

Poster P6499 at ACG 2026 looked at TikTok videos about reflux and the gut microbiome and found that a substantial share had the features of misleading or low-quality health information, and that those videos drew more engagement. The most common red flag the team found was broad, unsupported claims. The summary gives no counts, so we don’t print any. It is a fair test for anything in a feed, ours included: does the post say what its claim is based on, and is the claim as big as the evidence under it?

Ginger: Ginger beat placebo for indigestion in four trials

At ACG 2026, poster P4434 pooled four randomized, double-blind, placebo-controlled trials, 267 patients in all, of ginger-based treatments for functional dyspepsia, the long-running indigestion that tests do not trace to an ulcer or other visible cause. Ginger did better than placebo on overall symptom response, with improvements reported in fullness after meals, feeling full early, bloating, nausea and upper-belly discomfort, and it was generally well tolerated. The catch: four trials is not many, they used different formulations, and the authors say the results should not be assumed to apply to every ginger supplement on a shelf. It is not a verdict on the ginger shot in your fridge. The authors suggest anyone interested talk it through with a clinician, especially if they take other medications. Our bloating guide has the wider picture.

Stool tests: Most people with a positive at-home stool test had no colonoscopy on record a year later

The mailed stool test is how a lot of people, and a lot of parents, now screen for colon cancer. Poster P2791 at ACG 2026 followed 53,776 adults across several health systems whose stool-based screening test came back positive. Only 40.8 percent had a documented colonoscopy or sigmoidoscopy within a year; 59.2 percent had none on record. A positive result does not mean cancer, the authors write, but it does mean the follow-up is needed, and the screening is not finished until it happens.

Sleep: How well you sleep, not how long, tracked with fatty liver

The liver is part of the digestive system, and ACG 2026 poster P1704 is about it. Using the national NHANES health survey for 2017 to 2023, with liver fat measured by an ultrasound-based scan rather than by self-report, the authors found that short sleep was not linked to fatty liver disease once other factors were accounted for. Sleep quality was: trouble sleeping came with 1.30 times the odds and frequent daytime sleepiness with 1.65 times, even after adjusting for weight and metabolic health. The condition is now called MASLD, short for metabolic dysfunction-associated steatotic liver disease, the current name for fatty liver. The catch is that this is a single snapshot of survey data, so it shows a link, not a cause.

Also flagged: The rest of the list, briefly

GLP-1 drugs and a bleeding condition. In a look back at patient records, people with angiodysplasias, fragile blood vessels in the gut lining that bleed, who were taking GLP-1 drugs (the Ozempic family) had 73 percent lower risk of hospitalization for gut bleeding than people on the current standard drugs; the patients in it had diabetes or obesity. The authors say it does not prove cause and that no one should start or change a medication based on it. Our Ozempic explainer covers the everyday gut side.

Afternoon colonoscopies. Procedures scheduled in the afternoon, and the length of the doctor’s lunch break, made no difference to quality, poster P0864 found. Live vaccines in IBD. Among 220 people on immune-modifying IBD treatment who were given a live vaccine by mistake, no one developed a vaccine-related infection; the authors stress that live vaccines are still not recommended for this group. Sleep apnea and reflux. Poster P5213, on whether CPAP machines ease reflux, is presented Tuesday; its summary was not out when we published, and we will add it. The other flagged studies are drug trials for eosinophilic esophagitis, ulcerative colitis and liver scarring, fertility treatment outcomes in women with IBD, AI-read capsule cameras, fatty liver and IBD treatment, and phone-based consent forms.

How we read these: Abstracts, not papers

A conference abstract is a short summary of a study, chosen for the meeting by reviewers but not yet put through the full peer review of a journal paper, and its numbers can change when the paper comes out. The full abstracts are published in the October 2026 supplement of The American Journal of Gastroenterology, volume 121, issue 10S1, which is behind a subscription; we link each one. Every number above comes from the authors’ own notes on the college’s newsworthy-abstracts page, read October 12, and the meeting details from its FAQ. Where a summary gives no number, we print none. We will update this page as the rest of the meeting is presented, and again when any of these become full papers.

Gut Health Times has no relationship with the American College of Gastroenterology or with any author named here, and none of them reviewed this article. This article is educational, describes what the cited summaries say, and is not medical advice.