Recent research has shed new light on the powerful role the gut microbiome plays in combating colorectal cancer. The study highlights how short-chain fatty acids (SCFAs), produced when gut bacteria break down dietary fiber, may influence gene activity to prevent cancer growth. This underscores the critical importance of fiber in our diets, a nutrient often undervalued in many Western countries, including the United States.
The gut microbiome consists of millions of bacteria and other microorganisms that assist in digesting what we consume. Fiber, an essential component of a healthy diet, not only aids in preventing constipation and maintaining a healthy weight, but also supports overall gut health. The UK recommends a daily intake of 30 grams of fiber, yet less than 10% of Americans meet this recommendation. In the UK, average fiber consumption is only about 60% of the suggested amount.
Researchers have zeroed in on SCFAs such as propionate and butyrate, which arise from the breakdown of dietary fiber by gut bacteria. These compounds have been found to influence gene expression, potentially reducing cancer risk. Through modifying histones, proteins that package DNA, SCFAs can switch certain genes on or off, depending on cell types and conditions. This mechanism may explain how eating enough fiber could increase SCFA production in the gut, thus supporting healthier gene regulation and potentially preventing colorectal cancer.
“Eating enough fiber increases SCFA production in the gut, which may help prevent colorectal cancer by supporting healthy gene regulation. It’s a clear reminder of how closely diet and health are linked. [It] opens exciting doors for using diet and gut health to influence gene activity and prevent disease.” — Şebnem Ünlüişler
The study emphasizes that fruits, nuts and seeds, vegetables, and whole grains are excellent sources of fiber. Despite this, the average fiber intake in the U.S. remains around 17 grams per day—far below the recommended levels for both men and women. This gap in fiber consumption underscores the need for greater awareness and dietary changes.
“Regardless of the findings from this study, we should be aiming for the [UK] recommendations of 30 grams of fiber per day every day. Unfortunately, few people actually meet these recommendations. The findings of the study add to the already known evidence base that fiber is crucial for health both in terms of human health and the gut microbiome which directly affects our colonic [gut] health.” — Eamon Laird
SCFAs like propionate and butyrate are at the forefront of research concerning cancer prevention. These SCFAs play a vital role in influencing the activity of both proto-oncogenes (which promote cancer) and tumor-suppressor genes by altering histones. This process makes DNA more accessible, allowing for changes in gene activity that may prevent cancer.
“The research focuses on short-chain fatty acids (SCFAs) like propionate and butyrate, which are produced when gut bacteria break down dietary fiber. These SCFAs can influence the activity of both cancer-promoting (proto-oncogenes) and cancer-suppressing (tumor-suppressor) genes by modifying histones, the proteins that help package DNA. By making the DNA more accessible, SCFAs can turn certain genes on or off, depending on the cell type and conditions.” — Şebnem Ünlüişler
While these findings are promising, experts caution that this study's scope is limited to cell line variations and laboratory settings. The typical diet and lifestyle can significantly affect these compounds' potential effects when translated to real-life scenarios.
“This is a well-run and comprehensive cell study with good methodologies but limited in scope — there are further questions to ask with many cell line variations and also real-life scenarios — the typical diet and lifestyle will have major effects, and it is unknown if these compounds still display these potential effects in the field, so to speak.”
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