Can Dietary Fiber Rewrite Your Genetic Code to Combat Cancer?

In this episode of Daily Value, we take a look at how fiber fuels anti-cancer gene activity - emphasizing the role of short-chain fatty acids (SCFAs) produced during fiber fermentation. Drawing on new research PMID: 39789354) published in Nature Metabolism out of Stanford Medicine, we examine how fiber-derived metabolites influence gene activity to reduce cancer risk and promote overall health.

Discussion Points:

• The epigenetic role of SCFAs, such as butyrate and propionate, in activating anti-cancer genes and inhibiting harmful pathways.
• Insights from recent studies, including findings showing a 10% reduction in colorectal cancer risk for every 10-gram increase in daily fiber intake.
• Practical strategies to optimize fiber consumption, including food sources and supplementation options tailored for individual needs.

https://pubmed.ncbi.nlm.nih.gov/39789354/

Transcript

Speaker 0 0:00

Can fiber really alter your DNA to fight cancer ? Well , groundbreaking research out of Stanford Medicine says yes . Hello everyone , and welcome back to Daily Value . I'm William Wallace , and today we're focusing on a dietary component that mounting evidence suggests plays an important role in cancer prevention , and that is fiber . Drawing from recent high-quality studies and comprehensive reviews , we're going to uncover exactly how dietary fiber and , importantly , the metabolic byproducts of fiber metabolism , known as short-chain fatty acids , function as protective agents against multiple forms of cancer . One recent study that brought this topic on showed just how short-chain fatty acids like propionate and butyrate may be directly altering gene expression in cancer cells to exert their anti-cancer effects .

Speaker 0 0:53

Fiber intake recommendations vary by region , but general guidelines suggest 25 grams per day for women and 38 grams per day for men . Unfortunately , most people fall far short of these targets . In the United States , the average daily fiber intake is only about 15 grams , while in Europe it's slightly higher , but still below recommended levels . This widespread deficiency highlights the importance of increasing fiber consumption to achieve its full health benefits , which include cancer prevention . As we'll get into , fiber is more than a single entity . It's a diverse group of plant-derived carbohydrates classified by their degree of polymerization and digestibility Non-digestible carbohydrates , dietary fiber that is , are divided into short-chain , also called low-molecular-weight fibers , and long-chain , also called high-molecular-weight fiber types . Low-molecular-weight fibers , like oligosaccharides and inulin , are rapidly fermentable and act as prebiotics in the gut , while high-molecular fibers , such as non-starch polysaccharides , provide bulk and are not fermented as rapidly . Through microbial fermentation , these fibers produce what are called short-chain fatty acids , potent epigenetic regulators that influence chromatin structure and gene activity . Now think of chromatin as a spool of thread where your DNA is the thread . It helps to pack long strands of DNA neatly into a cell's nucleus , depending on how tightly it's packed , genes can either be easily accessed and turned on , or tightly locked away and turned off .

Speaker 0 2:37

Short-chain fatty acids like butyrate and propionate act as what are called acyl donors , meaning they provide chemical groups that modify histones , which are proteins around which DNA is wrapped . These modifications open up or close down access to certain genes , directly influencing their activity and playing a key role in cellular processes like growth and differentiation of cells . Now a study published just days ago in the journal Nature Metabolism looked at how fiber-derived short-chain fatty acids like propionate and deuterate influence gene activity in normal and cancerous cells . Particularly in colorectal cancer cells . Short-chain fatty acids were found to modify proteins called histones , which again help control how tightly DNA is packed and how accessible genes are for activation . These modifications were then mapped across the genome to identify their impact . What the researchers discovered was that short-chain fatty acids help make certain genes more active by loosening the structure of DNA in certain regions . This is especially important for genes that control cell growth and stress responses . Deuterates specifically blocked harmful processes in cancer cells by inhibiting enzymes called histone deacetylases . By inhibiting enzymes called histone deacetylases , this led to increased activation of anti-cancer genes and caused cancer cells to die while leaving healthy cells unaffected . The study showed that short-chain fatty acids influence major cancer-related pathways , which play a role in how cancer develops and spreads . The conclusion of the study was that dietary fiber , through its fermentation into short-chain fatty acids , can impact regulation and help reduce cancer risks by targeting specific cellular processes .

Speaker 0 4:33

High levels of butyrate in the gut correlate with increased histone acylation and chromatin accessibility of anti-proliferative genes . In fact , an Umbrella meta-analysis published by Hu et al in 2023 , so very recently found that for every 10 gram increase in daily fiber intake , the risk of colorectal cancer decreased by approximately 10% . Fiber's ability to reduce stool transit time and dilute carcinogenic or cancer-promoting substances in the colon may be another way that fiber protects against cancer , aside from short-chain fatty acid benefits that we just went over . The same review found that high fiber intake is linked to a 44% reduction in gastric cancer risk . Again , outside of the mechanisms outlined in this podcast , protection is thought to be due to fiber's ability to lower nitroso compounds , which are potent carcinogens formed in the stomach . The same review indicated a significant inverse relationship between fiber consumption and breast cancer risk , particularly in post-menopausal women . Increased fiber intake correlates with lower levels of harmful estrogen metabolites , which have been considered a major risk factor for breast cancer . Fiber has the ability to improve insulin sensitivity , which plays a role in reducing the risk of pancreatic cancer as well .

Speaker 0 6:01

Understanding the mechanistic pathways linking dietary fiber and short-chain fatty acids to cancer prevention opens avenues for clinical and dietary interventions . Targeted fiber supplementation focusing on butyrogenic substances like resistant starches could enhance short-chain fatty acid production in people with low microbial diversity . It's also possible that leveraging microbiota-based therapies to increase the abundance of butyrate-producing bacteria may serve as an adjunct to conventional cancer treatments . Increasing butyrate-producing bacterial species that's something that I've touched on before in previous episodes and will actually deep dive on in the near future .

Speaker 0 6:43

Short-chain fibers like inulin or other fructooligosaccharides found in onions , garlic and so on can be very efficient and quickly ferment in the gut . However , not everyone handles this rapid fermentation well , due to the rapid buildup of things like methane and hydrogen gas . For this reason , among a few others individuals who experience bloating or GI distress with these fiber types often people who would do well on a FODMAP protocol for a while they would likely respond better to longer chain fibers that ferment less rapidly . Cellulose is an example of a long chain fiber . This can be found in broccoli , green beans , oats and berries , resistant starch found in potatoes , rice , lentils and different beans , and then there's also lignans . These fibers can be found in flax seeds and sesame seeds . If you want to consider fiber supplements , psyllium husk has a good deal of data as a very beneficial long-chain fiber . This is the main active ingredient in the fiber supplement known as metamucil .

Speaker 0 7:47

Fiber is not merely a dietary accessory . It can be a key player in the intricate interplay between diet , metabolism and epigenetics Through the production of short-chain fatty acids like propionate and butyrate . Through its fermentation , fiber exerts multifaceted anti-cancer effects , from enhancing chromatin accessibility to modulating anti-inflammatory pathways . By integrating high-fiber foods and targeted supplements into daily routines , we can also harness these epigenetic tools to mitigate cancer risk and promote overall health . Thank you for tuning in to Daily Value . If you found this episode insightful , please share it with people you think who may benefit . Until next time , stay healthy .