Stanford researchers found that fiber digestion produces compounds that directly alter gene function, potentially preventing cancer.
Fiber is a crucial component of a healthy diet, yet fewer than 10% of Americans consume the recommended daily amount. However, new research from Stanford Medicine may provide a compelling reason to increase intake of fiber-rich foods like beans, nuts, cruciferous vegetables, and avocados.
The study, recently published in Nature Metabolism, reveals the direct epigenetic effects of two common byproducts produced during fiber digestion. Notably, some of these changes in gene expression exhibit anti-cancer properties.
When we eat fiber, the gut microbiome produces short-chain fatty acids. These compounds are more than just an energy source for us: They have long been suspected to indirectly affect gene function. The researchers traced how the two most common short-chain fatty acids in our gut, propionate, and butyrate, altered gene expression in healthy human cells, in treated and untreated human colon cancer cells, and in mouse intestines. They found direct epigenetic changes at specific genes that regulate cell proliferation and differentiation, along with apoptosis, or pre-programmed cell death processes — all of which are important for disrupting or controlling the unchecked cell growth that underlies cancer.
A Direct Link Between Fiber and Cancer Prevention
“We found a direct link between eating fiber and modulation of gene function that has anti-cancer effects, and we think this is likely a global mechanism because the short-chain fatty acids that result from fiber digestion can travel all over the body,” said Michael Snyder, PhD, Stanford W. Ascherman, MD, FACS Professor in Genetics. “It is generally the case that people’s diet is very fiber poor, and that means their microbiome is not being fed properly and cannot make as many short-chain fatty acids as it should. This is not doing our health any favors.”
Given the worrying rates of colon cancer in younger adults, the study findings could also spur conversation and research about the possible synergistic effects of diet and cancer treatment.
“By identifying the gene targets of these important molecules we can understand how fiber exerts its beneficial effects and what goes wrong during cancer,” Snyder added.
Reference: “Short-chain fatty acid metabolites propionate and butyrate are unique epigenetic regulatory elements linking diet, metabolism and gene expression” by Michael Nshanian, Joshua J. Gruber, Benjamin S. Geller, Faye Chleilat, Samuel M. Lancaster, Shannon M. White, Ludmila Alexandrova, Jeannie M. Camarillo, Neil L. Kelleher, Yingming Zhao and Michael P. Snyder, 9 January 2025, Nature Metabolism.
DOI: 10.1038/s42255-024-01191-9