A new study from City of Hope researchers indicates that a high-fiber diet could play a crucial role in reducing the risk of graft-versus-host disease (GVHD) and improving overall survival in patients undergoing bone marrow or stem cell transplants for blood cancer. The research, presented at the 2024 American Society of Hematology (ASH) annual meeting, highlights the beneficial impact of dietary fiber on the gut microbiome, which in turn may mitigate complications following transplantation.
GVHD is a common and potentially severe complication where donor cells attack the recipient's tissues. Current post-transplant dietary guidelines often advise patients to avoid high-fiber foods to minimize the risk of infection, but this new research challenges that approach.
Fiber's Impact on Gut Microbiome and GVHD
"We've known that dietary fiber plays a beneficial role regulating the immune system via the gut in healthy populations," said lead author Jenny Paredes, PhD, a staff scientist at City of Hope. "Our work now shows this may be true for transplant patients, too, and that dietary restrictions post-procedure that might result in low fiber intake could be counterproductive."
The study analyzed the diets of 173 transplant patients from 10 days before to 30 days after their procedures. Results showed that higher fiber intake was associated with a reduced risk of developing acute GVHD in the lower gastrointestinal tract and improved overall survival. Conversely, a low-fiber diet correlated with a less diverse gut microbiome, potentially increasing vulnerability to infection.
Butyrate Production and GVHD Protection
Notably, increased fiber consumption was linked to higher levels of butyrate-producing gut microbes. Butyrate, a short-chain fatty acid produced during fiber fermentation by the gut microbiota, has been previously shown to protect against GVHD.
To further explore these mechanisms, the researchers conducted a preclinical study using mouse models of GVHD. Mice fed a high-fiber diet rich in cellulose experienced a significant reduction in GVHD-related deaths and improved overall health. These mice also exhibited increased microbial diversity and higher concentrations of butyrate in their guts, mirroring the observations in human patients.
Potential for Nutritional Interventions
"While high-fiber diets may not be appropriate for everyone, this study shows the exciting potential for high fiber to play a role in reducing GVHD risk in transplant patients," Paredes said. "We look forward to designing a nutritional intervention for clinics that can help diversify the gut microbiome through food choice and improve outcomes for people receiving bone marrow or stem cell transplants."
The study was a collaborative effort with the Memorial Sloan Kettering Cancer Center and received funding from the National Cancer Institute and private foundations.
