Fasting primes gut repair after radiation in preclinical work

A 24-hour fast increased Akkermansia muciniphila and primed small-intestine repair after radiation damage in a PNAS preclinical study publicized Nov. 8 by MD Anderson.

The finding matters because abdominal radiation can injure healthy intestinal tissue, limiting treatment options; this work identifies a microbiome pathway, but not a tested patient intervention.

The study was co-led by Helen Piwnica-Worms, professor of Experimental Radiation Oncology, and Kunal Rai, professor of Genomic Medicine, at The University of Texas MD Anderson Cancer Center.

"Fasting helps prepare intestinal cells to respond more quickly and effectively after injury, almost like training the cells with an emergency preparedness plan," Piwnica-Worms said. "This study helps explain how that plan is organized and identifies a key bacterium involved in coordinating the response."

Researchers reported that fasting raised levels of Akkermansia muciniphila, also called AKK, in the small intestine. The bacterium produces propionate, a metabolite that helped trigger changes inside intestinal cells before radiation exposure.

Those changes involved histones, proteins that help package DNA. Chemical marks on histones can affect which genes become active without changing the DNA sequence itself, a mechanism the researchers linked to tissue-regeneration programs.

When researchers removed AKK, fasting no longer produced the same regenerative benefit. The response returned only when AKK was restored together with fasting, according to the report.

Radiation therapy is used for abdominal cancers including pancreatic, colorectal and gynecologic cancers. The small intestine is vulnerable because its lining is sensitive to radiation; injury can cause nausea, diarrhea, infections and severe complications.

The study cannot show that fasting before radiation protects people with cancer. It is preclinical research, and additional studies would be needed to test whether the same mechanism works safely in humans.

The result also should not be read as a fasting recommendation for patients. The researchers said the pathway might eventually be activated through targeted microbes, metabolites or dietary approaches without requiring food restriction during cancer care.

"Fasting is not always practical for cancer patients, and this work supports several other potential ways to enhance recovery after treatment," Rai said. "Whether through dietary interventions, targeted microbes or their metabolites, the goal is to help repair healthy tissue more effectively while patients receive the cancer therapies they need."

The research was funded by the National Cancer Institute within the National Institutes of Health and the Cancer Prevention and Research Institute of Texas.

Source: ScienceDaily Health report on University of Texas MD Anderson Cancer Center research and Proceedings of the National Academy of Sciences paper, Nov. 8, 2026.

Atlas360 reports health research and does not provide medical advice.