When 12-year-old Mia faces her chemotherapy appointments, she often feels sick to her stomach afterward. Radiation treatment — high-energy beams used to kill cancer cells — can damage the healthy lining of the intestines, causing nausea, diarrhea and serious infections. These side effects often force doctors to use lower doses of radiation than they would like.
But scientists at MD Anderson Cancer Center in Houston may have found a simple solution hiding inside our own guts: a tiny bacterium that teams up with short-term fasting to help the small intestine heal itself.
In a new study published in the journal Proceedings of the National Academy of Sciences, researchers discovered that skipping food for just 24 hours causes a beneficial gut bacterium called Akkermansia muciniphila — or AKK — to multiply in the small intestine. When AKK is present, it produces a small molecule called propionate. This molecule teams up with other changes caused by fasting to place chemical tags on proteins called histones, which act like spools holding DNA in place inside cells.
These chemical tags act like an early warning system. They unwrap DNA from the histones, preparing a special group of intestinal cells to turn on repair genes before radiation damage even occurs. Think of it like having emergency instructions already loaded on your phone — the cells are ready to fix themselves faster once injury happens.
"Fasting helps prepare intestinal cells to respond more quickly and effectively after injury, almost like training the cells with an emergency preparedness plan," said Dr. Helen Piwnica-Worms, one of the study's lead researchers and a professor of Experimental Radiation Oncology at MD Anderson.
The research team confirmed AKK's importance by removing the bacterium from some mice and leaving it in others. The mice without AKK did not recover as well after radiation, while mice with AKK regenerated their intestinal lining normally — as long as they had fasted. When researchers added AKK back to the diet of mice that had lost it, the healing benefits returned.
"This study helps explain how that plan is organized and identifies a key bacterium involved in coordinating the response," Piwnica-Worms said.
The findings open doors for new ways to help cancer patients. Since not all patients can safely skip meals, researchers are now exploring whether giving patients AKK bacteria directly — or even just the propionate molecule it produces — could mimic fasting's protective effects without requiring patients to go hungry.
"Fasting is not always practical for cancer patients, and this work supports several other potential ways to enhance recovery after treatment," said Dr. Kunal Rai, a co-leader of the study and professor of Genomic Medicine. "Whether through dietary interventions, targeted microbes or their metabolites, the goal is to help repair healthy tissue more effectively."
The team plans to study whether this same healing pathway could protect other fast-growing tissues in the body, like bone marrow, which also gets damaged during some cancer treatments. If future clinical trials confirm these results, patients receiving radiation for abdominal cancers could one day face fewer side effects and receive stronger, safer doses of treatment.