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/

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Episode Transcript

Speaker 0 (00:00):
Can fiber really alter your DNA to fight cancer?
Well, groundbreaking researchout of Stanford Medicine says
yes.
Hello everyone, and welcomeback to Daily Value.
I'm William Wallace, and todaywe're focusing on a dietary
component that mounting evidencesuggests plays an important
role in cancer prevention, andthat is fiber.

(00:21):
Drawing from recenthigh-quality studies and
comprehensive reviews, we'regoing to uncover exactly how
dietary fiber and, importantly,the metabolic byproducts of
fiber metabolism, known asshort-chain fatty acids,
function as protective agentsagainst multiple forms of cancer
.
One recent study that broughtthis topic on showed just how

(00:43):
short-chain fatty acids likepropionate and butyrate may be
directly altering geneexpression in cancer cells to
exert their anti-cancer effects.
Fiber intake recommendationsvary by region, but general
guidelines suggest 25 grams perday for women and 38 grams per
day for men.
Unfortunately, most people fallfar short of these targets.

(01:06):
In the United States, theaverage daily fiber intake is
only about 15 grams, while inEurope it's slightly higher, but
still below recommended levels.
This widespread deficiencyhighlights the importance of
increasing fiber consumption toachieve its full health benefits
, which include cancerprevention.
As we'll get into, fiber ismore than a single entity.

(01:28):
It's a diverse group ofplant-derived carbohydrates
classified by their degree ofpolymerization and digestibility
Non-digestible carbohydrates,dietary fiber that is, are
divided into short-chain, alsocalled low-molecular-weight
fibers, and long-chain, alsocalled high-molecular-weight

(01:48):
fiber types.
Low-molecular-weight fibers,like oligosaccharides and inulin
, are rapidly fermentable andact as prebiotics in the gut,
while high-molecular fibers,such as non-starch
polysaccharides, provide bulkand are not fermented as rapidly
.
Through microbial fermentation,these fibers produce what are

(02:10):
called short-chain fatty acids,potent epigenetic regulators
that influence chromatinstructure and gene activity.
Now think of chromatin as aspool of thread where your DNA
is the thread.
It helps to pack long strandsof DNA neatly into a cell's
nucleus, depending on howtightly it's packed, genes can

(02:31):
either be easily accessed andturned on, or tightly locked
away and turned off.
Short-chain fatty acids likebutyrate 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.

(02:51):
These modifications open up orclose down access to certain
genes, directly influencingtheir activity and playing a key
role in cellular processes likegrowth and differentiation of
cells.
Now a study published just daysago in the journal Nature
Metabolism looked at howfiber-derived short-chain fatty

(03:14):
acids like propionate anddeuterate influence gene
activity in normal and cancerouscells.
Particularly in colorectalcancer cells.
Short-chain fatty acids werefound to modify proteins called
histones, which again helpcontrol how tightly DNA is
packed and how accessible genesare for activation.

(03:35):
These modifications were thenmapped across the genome to
identify their impact.
What the researchers discoveredwas that short-chain fatty
acids help make certain genesmore active by loosening the
structure of DNA in certainregions.
This is especially importantfor genes that control cell
growth and stress responses.

(03:55):
Deuterates specifically blockedharmful processes in cancer
cells by inhibiting enzymescalled histone deacetylases.
By inhibiting enzymes calledhistone deacetylases, this led
to increased activation ofanti-cancer genes and caused
cancer cells to die whileleaving healthy cells unaffected
.
The study showed thatshort-chain fatty acids
influence major cancer-relatedpathways, which play a role in

(04:18):
how cancer develops and spreads.
The conclusion of the study wasthat dietary fiber, through its
fermentation into short-chainfatty acids, can impact
regulation and help reducecancer risks by targeting
specific cellular processes.
High levels of butyrate in thegut correlate with increased
histone acylation and chromatinaccessibility of

(04:41):
anti-proliferative genes.
In fact, an Umbrellameta-analysis published by Hu et
al in 2023, so very recentlyfound that for every 10 gram
increase in daily fiber intake,the risk of colorectal cancer
decreased by approximately 10%.
Fiber's ability to reduce stooltransit time and dilute

(05:03):
carcinogenic or cancer-promotingsubstances in the colon may be
another way that fiber protectsagainst cancer, aside from
short-chain fatty acid benefitsthat we just went over.
The same review found that highfiber intake is linked to a 44%
reduction in gastric cancerrisk.
Again, outside of themechanisms outlined in this

(05:24):
podcast, protection is thoughtto be due to fiber's ability to
lower nitroso compounds, whichare potent carcinogens formed in
the stomach.
The same review indicated asignificant inverse relationship
between fiber consumption andbreast cancer risk, particularly
in post-menopausal women.
Increased fiber intakecorrelates with lower levels of

(05:47):
harmful estrogen metabolites,which have been considered a
major risk factor for breastcancer.
Fiber has the ability toimprove insulin sensitivity,
which plays a role in reducingthe risk of pancreatic cancer as
well.
Understanding the mechanisticpathways linking dietary fiber
and short-chain fatty acids tocancer prevention opens avenues

(06:07):
for clinical and dietaryinterventions.
Targeted fiber supplementationfocusing on butyrogenic
substances like resistantstarches could enhance
short-chain fatty acidproduction in people with low
microbial diversity.
It's also possible thatleveraging microbiota-based
therapies to increase theabundance of butyrate-producing

(06:29):
bacteria may serve as an adjunctto conventional cancer
treatments.
Increasing butyrate-producingbacterial species that's
something that I've touched onbefore in previous episodes and
will actually deep dive on inthe near future.
Short-chain fibers like inulinor other fructooligosaccharides
found in onions, garlic and soon can be very efficient and

(06:51):
quickly ferment in the gut.
However, not everyone handlesthis rapid fermentation well,
due to the rapid buildup ofthings like methane and hydrogen
gas.
For this reason, among a fewothers individuals who
experience bloating or GIdistress with these fiber types
often people who would do wellon a FODMAP protocol for a while

(07:11):
they would likely respondbetter to longer chain fibers
that ferment less rapidly.
Cellulose is an example of along chain fiber.
This can be found in broccoli,green beans, oats and berries,
resistant starch found inpotatoes, rice, lentils and
different beans, and thenthere's also lignans.
These fibers can be found inflax seeds and sesame seeds.

(07:33):
If you want to consider fibersupplements, psyllium husk has a
good deal of data as a verybeneficial long-chain fiber.
This is the main activeingredient in the fiber
supplement known as metamucil.
Fiber is not merely a dietaryaccessory.
It can be a key player in theintricate interplay between diet
, metabolism and epigeneticsThrough the production of

(07:57):
short-chain fatty acids likepropionate and butyrate.
Through its fermentation, fiberexerts multifaceted anti-cancer
effects, from enhancingchromatin accessibility to
modulating anti-inflammatorypathways.
By integrating high-fiber foodsand targeted supplements into
daily routines, we can alsoharness these epigenetic tools

(08:20):
to mitigate cancer risk andpromote overall health.
Thank you for tuning in toDaily Value.
If you found this episodeinsightful, please share it with
people you think who maybenefit.
Until next time, stay healthy.