“An apple a day keeps the doctor away,” says the old proverb, and science suggests it’s not far from the truth. As we’ve discussed before on this blog, diet plays a key role in overall health. Research continues to highlight the connection between following a healthy diet and long-term well-being. Yet, many of us don’t get enough fiber in our daily diets.
Now, a new study led by Stanford Medicine researchers could convince us to fill our plates with whole grains, vegetables, fruits, legumes, nuts —all fiber-rich foods and the preferred meal of our gut microbiota.
Published in Nature Metabolism, the research shows that two key byproducts of fiber digestion can influence gene expression and play an important role in cancer prevention.
How fiber fuels our gut and our health
When we consume dietary fiber, bacteria in our intestines break it down, producing short-chain fatty acids (SCFAs). These molecules not only serve as an energy source but also provide significant health benefits. Scientists have long suspected that SCFAs might also influence gene function in some way.
Researchers at Stanford University have confirmed this idea. In a study using healthy human cells, colon cancer cells, and mouse intestines, they traced how two specific SCFAs —butyrate and propionate—induce epigenetic changes. These modifications in gene expression act like dimmers switches, regulating the intensity of gene activity. The affected genes are linked to cell proliferation, differentiation, and the processes of diseased or damaged cell death, all of which are crucial for controlling cancer progression.
“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, Professor in Genetics and author of the study.
The researchers successfully identified the gene targets of SCFAs, which are produced in significant amounts by gut microbiota. This discovery enables a deeper understanding into how dietary fiber imparts its health benefits and elucidates the genetic changes that occur during cancer, according to Prof Snyder. For example, they observed that butyrate can directly modify specific regions of the genome, leading to the regulation of cancer cell growth.
Making fiber a daily habit
In their study, the researchers emphasized the significant benefits of consuming fiber and the fundamental role microbial products play in disease prevention, particularly given the rising rates of colon cancer among younger adults.
According to the researchers, in general nowadays people’s diets lack adequate amounts of fiber, which results in their microbiomes not being properly nourished and, consequently, being unable to produce sufficient short-chain fatty acids. This issue arises concurrently with growing evidence linking low fiber intake to conditions such as obesity, diabetes, and cancer— diseases that are becoming more prevalent worldwide.
Since diet has a profound impact on health, ensuring proper nourishment of our microbiome with fiber-rich foods, and understanding how this can protect us from various diseases, provides a compelling reason to incorporate more fiber into our daily diet. So, bon appétit!
Reference:
Nshanian, M., Gruber, J.J., Geller, B.S. et al. Short-chain fatty acid metabolites propionate and butyrate are unique epigenetic regulatory elements linking diet, metabolism and gene expression. Nat Metab 7, 196–211 (2025). https://doi.org/10.1038/s42255-024-01191-9