Summary: New research shows that fiber digestion produces short-chain fatty acids—most notably propionate and butyrate—that directly change gene activity through epigenetic modifications and can produce anti-cancer effects. The study mapped how these metabolites alter the regulation of genes that control cell proliferation, differentiation and programmed cell death, processes that are central to limiting tumor growth.
The investigators demonstrated these epigenetic effects in cultured human cells, in colon cancer cell models, and in mouse intestines, underlining how dietary fiber, via the gut microbiome, can have a systemic influence on gene regulation and health. With fewer than 10% of Americans consuming the recommended daily amount of fiber, these findings highlight an actionable dietary pathway that may contribute to cancer prevention.
Key Facts
- Anti-cancer effects: Propionate and butyrate—two common short-chain fatty acids produced when the microbiome ferments fiber—directly influence the epigenetic marks that regulate genes involved in cell growth, differentiation and apoptosis.
- Systemic mechanism: These metabolites circulate beyond the gut, suggesting that the benefits of a high-fiber diet may extend widely across tissues by altering gene function.
- Dietary gap: Less than 10% of Americans meet recommended fiber intake, potentially limiting the production of protective short-chain fatty acids.
Source: Stanford
Fiber is a well-established component of a healthy diet, but most people fall short of recommended intake levels.
A team at Stanford Medicine reports new evidence that may encourage greater consumption of beans, nuts, cruciferous vegetables, avocados and other fiber-rich foods. The study, appearing in Nature Metabolism on Jan. 9, identifies direct epigenetic roles for two abundant fiber-derived metabolites and links those changes to cellular programs that can counteract cancerous growth.
When dietary fiber reaches the colon it is fermented by gut microbes into short-chain fatty acids (SCFAs). Beyond serving as an energy source for colon cells, these metabolites have long been suspected of influencing gene regulation. The Stanford team focused on propionate and butyrate, the two most prevalent SCFAs, to trace how they change chromatin marks and affect gene expression.
Using a combination of experiments in healthy human cells, treated and untreated human colorectal cancer cell lines, and in vivo mouse intestinal tissue, the investigators mapped where these SCFA-related histone modifications occur and how they correlate with chromatin accessibility and transcriptional activity. They report direct epigenetic changes at genomic regions that control growth, differentiation and programmed cell death—mechanisms that can slow or prevent tumor development.
“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. He emphasized that a fiber-poor diet limits the microbiome’s ability to produce SCFAs, which may reduce this natural protective influence on gene regulation.
Given rising concerns about colorectal cancer in younger adults, these results also encourage further study of how diet might interact with cancer therapies. By identifying the specific genomic targets of propionate and butyrate, researchers can better understand how fiber supports normal cell regulation and what patterns change during cancer development.
About this diet, cancer, and genetics research news
Author: Lisa Kim
Source: Stanford
Contact: Lisa Kim – Stanford
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Short-chain fatty acid metabolites propionate and butyrate are unique epigenetic regulatory elements linking diet, metabolism and gene expression” by Michael Snyder et al. Nature Metabolism
Abstract
Short-chain fatty acid metabolites propionate and butyrate are unique epigenetic regulatory elements linking diet, metabolism and gene expression
Propionate and butyrate—two short-chain fatty acids produced in large quantities by microbial fermentation of dietary fiber—have been associated with multiple health benefits and have been identified as contributors to distinctive acyl lysine histone marks. To clarify how these histone modifications function, the researchers used chromatin immunoprecipitation followed by sequencing to map four short-chain acyl histone marks (H3K18pr, H3K18bu, H4K12pr and H4K12bu) across the genome in both treated and untreated colorectal cancer (CRC) cells, in normal cell lines and in mouse intestinal tissue in vivo.
They integrated these histone maps with measures of chromatin openness and gene expression to determine the functional impact of the modified regions. The data indicate that propionate and butyrate associate with and promote activity at genes involved in growth control, cellular differentiation and ion transport. The authors propose a model in which SCFAs directly modify specific genomic sites, increasing chromatin accessibility and, in the case of butyrate, producing divergent effects on proliferation in normal versus colorectal cancer cells.