A recent study reveals that gut bacteria, through the production of short-chain fatty acids (SCFAs) when breaking down dietary fiber, may play a crucial role in preventing colorectal cancer. The research underscores the health benefits of fiber, an essential dietary component, which remains under-consumed by most Americans and Britons. Despite recommendations for a daily intake of 30 grams, U.S. adults average around 17 grams, with less than 10% meeting the suggested amount. This shortfall is even more pronounced in the UK, where average consumption is only about 60% of the recommended level.
Fiber is vital for maintaining a healthy gut, preventing constipation, and aiding in weight management. The gut microbiome, consisting of millions of bacteria and microorganisms, assists in digesting food. When these bacteria break down plant fiber, they produce SCFAs such as propionate and butyrate. These compounds can turn specific genes on or off, enhancing DNA accessibility and potentially suppressing cancer growth by modulating gene activity.
“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 highlights the importance of fiber not only for general health but also for its specific role in cancer prevention. Whole grain foods like freekeh, bulgur wheat, and brown rice are excellent sources of fiber. Additionally, fruits such as avocados, apples, pears, and raspberries contribute significantly to fiber intake, as do nuts, seeds, and vegetables including legumes, potatoes, sweet potatoes, broccoli, and squashes.
“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 can influence cancer-promoting proto-oncogenes and cancer-suppressing tumor-suppressor genes by modifying histones—proteins that package DNA. This modification makes DNA more accessible, allowing SCFAs to regulate gene expression according to cell type and conditions.
“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
The comprehensive nature of this research highlights its potential impact on dietary recommendations and cancer prevention strategies. However, experts caution that while the study is well-conducted with robust methodologies, it remains limited in scope. There are still many questions concerning how these findings translate to real-life scenarios involving varied diets and lifestyles.
“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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