Last Updated on January 2, 2018 by Patricia Carter

SUMMARY:  This is not a 1950s sci-fi movie. This is what is likely happening now in your gut according to an amazing study just now publishing in Cell. If you are eating the Standard American Diet, the normal, helpful bacteria in your gut are not getting natural whole food fiber. Instead they are being fed fiber additives supplemented in processed foods, or isolated fiber supplements you are buying. Surprisingly, both the fiber additives and the supplements FAIL to feed your microbiome, and instead, they CANNIBALIZE the mucus lining for fuel, at least for mice, according to this study. Repeat:  Fiber Additives Starve Gut Microbes. They Eat Mucus Lining.  That compromises the intestinal barrier role in preventing pathogen infection. Bottom line: EAT WHOLE FOOD BASED FIBER to feed your microbiome, AND DON’T COUNT ON THE FIBER ADDED IN PROCESSED FOODS OR THE SUPPLEMENTS YOU TAKE FOR THAT FIBER. No wonder so many are sick.

“While this work was in mice, the take-home message from this work for humans amplifies everything that doctors and nutritionists have been telling us for decades: Eat A LOT OF FIBER FROM DIVERSE NATURAL SOURCES,” says Martens. “Your diet directly influences your microbiota, and from there it may influence the status of your gut’s mucus layer and tendency toward disease. But it’s an open question of whether we can cure our cultural lack of fiber with something more purified and easy to ingest [fiber supplements or that added to processed foods] than a lot of broccoli.”  —Eric Martens, Ph.D., an associate professor of microbiology at the University of Michigan Medical School who led the research along with his former postdoctoral fellow Mahesh Desai, Ph.D., now at the Luxembourg Institute of Health.

The  importance of eating lots of variety, or diversity, of whole food fiber.  

Different fiber types work together to maintain optimal digestive health.  “We can’t expect all fibers to have the same functions, just like we don’t expect all vitamins to have the same functions.  Mixing different types of naturally occurring fibers will ensure that they work together and be as beneficial as possible.” —Dr. Julie Miller Jones, professor emeritus at St. Catherine University, at the 12th symposium at IFT15: Where Science Feeds Innovation,  —Consumers should seek a variety of fiber sources to get the maximum health benefits.

This is spot on with the American Gut microbiome findings that while 6 different vegetables each week is good, 30 differing is best. Read that post here.  

Most Americans eat very little fiber, and the fiber they do eat is not whole food high fiber options. 

The US average actual fiber consumption is 18 grams per day for men while women ingest about 15 grams.  The recommended daily fiber intake for men is 38 grams of fiber per day, for women the number is 25 grams. The number of Americans who said they are trying to eat more fiber declined from 73% in 2010 to 53% in 2014. The Healthy People 2010 initiative set a goal of 2 fruits and 3 vegetables a day to help adults get the recommended amount of fiber, but just 32% eat that amount of fruit and only 26% eat three vegetables.  Further, those figures are misleading because when consumers choose fruits or vegetables, it’s often low fiber options, such as one piece of lettuce and a thin slice of tomato on a sandwich.  —Jones 2015, at the 12th symposium at IFT15: Where Science Feeds Innovation.

The 2016 Cell study details:

1. The researchers used specially born and raised mice having no gut microbes of their own, that then receive a transplant of 14 bacteria that normally grow in the human gut.
2. The study looked at the impacts of diet with differing fiber content and those with no fiber, and the researchers looked to see how the microbiota reacted to that fuel.
3. The researchers then infected some of the mice with certain strains of the bacteria Escherichia coli which causes gut infections in mice that are similar to that which occur in humans. The infections lead to irritation, inflammation, diarrhea, and more.

The study found that in mice, Fiber Additives Starve Gut Microbes — They Eat the Gut Mucus Lining.

All diets except for the natural whole food diet comprised of 15% fiber from minimally processed grains and plants, starved the gut microbiota.  

When fed those diets of fiber additives, the microbiota was starved and the helpful bacteria began to munch on the natural layer of mucus that lines the gut, eroding it to the point where dangerous invading bacteria could infect the colon wall.

A diet having about 15 percent fiber from minimally processed grains and plants:

allowed the mucus layer to stay thick, and the infection didn’t take full hold.

What Happened in the No fiber Diet:

When the researchers substituted a diet with no fiber in it, even for a few days, some of the microbes in their guts began to munch on the mucus. They observed that the more dangerous E. coli-like bacteria called Citrobacter rodentium flourished more in the guts of mice fed a fiber-free diet. Many of those mice began to show signs of illness and lost weight.  

[Updated Nov 19, 2016]  In reply to your comments, you are correct, I have mentioned another lab, the Sonnenburg Lab, and their analysis that elimination of microbiota-accessible carbohydrates (MACs) from the diet results in thinner mucus, increased proximity of microbes to the epithelium, and heightened expression of inflammatory markers.  MACS is a great new term because it means “the main component of dietary fiber that serve as the primary metabolic input for the gut microbiota” aka fuel for the microbiome.  The Sonnenburg published findings are,  Quantitative Imaging of Gut Microbiota Spatial Organization, Oct. 2015.  

What does that look like?

What Happened in a Diet that was Rich in Prebiotic Fiber in a purified form of soluble fiber that is similar to what some processed foods and supplements currently contain:

That diet resulted in the SAME erosion of the mucus layer as observed in the lack of fiber.

The bacteria that flourished are those that preferred the fuel provided — no surprise there…

For the low-fiber and no-fiber conditions, the four bacteria strains that flourished the most were the only ones that make enzymes that are capable of breaking down the long molecules called glycoproteins that make up the mucus layer.

The researchers could see which fiber-digesting enzymes the bacteria were making. They detected more than 1,600 different enzymes capable of degrading carbohydrates – similar to the complexity in the normal human gut. The researchers found that the mix of enzymes being made changed depending on what the mice were being fed, with even occasional fiber deprivation leading to more production of mucus-degrading enzymes.

The mucus layer images tell the story

Images of the mucus layer, and the “goblet” cells of the colon wall that produce the mucus constantly, showed that for a diet having reduced fiber the layer was thinner, and in the presence of the infection, the mucus layer was thin and patchy with inflammation spanning a wide area. Mice having a fiber-rich diet before being infected also had some inflammation, but it was across a much smaller area.  That means they were better protected from the infection.

Mucus production

While mucus is constantly being produced and degraded in a normal gut, the change in bacteria activity under the lowest-fiber conditions meant that the pace of eating was faster than the pace of production – almost like an overzealous harvesting of trees outpacing the planting of new ones.

“While this work was in mice, the take-home message from this work for humans amplifies everything that doctors and nutritionists have been telling us for decades: Eat A LOT OF FIBER FROM DIVERSE NATURAL SOURCES,” says Martens. “Your diet directly influences your microbiota, and from there it may influence the status of your gut’s mucus layer and tendency toward disease. But it’s an open question of whether we can cure our cultural lack of fiber with something more purified and easy to ingest [fiber supplements or that added to processed foods] than a lot of broccoli.”

Here’s what a Whole Foods Diet looks like 

Source: biomeonboardawareness.com/

carotenoids1

Source: International Carotenoid Society, http://www.carotenoidsociety.org/

Source: biomeonboardawareness.com/omega-3-fatty-oily-wild-caught-salmon

Source: Diet more powerful than pillbox, https://biomeonboardawareness.com/

Study and related links

A Dietary Fiber-Deprived Gut Microbiota Degrades the Colonic Mucus Barrier and Enhances Pathogen Susceptibility, Nov 17, 2016, Volume 167, Issue 5, p1339–1353.e21, DOI: http://dx.doi.org/10.1016/j.cell.2016.10.043

University of Michigan Health System, High-Fiber Diet Keeps Gut Microbes From Eating The Colon’s Lining, Protects Against Infection, Animal Study Shows

High-fiber diet keeps gut microbes from eating the colon’s lining, protects against infection, animal study shows,

Eating fiber keeps gut microbes from eating you, 

Quantitative Imaging of Gut Microbiota Spatial Organization, Oct. 2015  — Sonnenburg published findings, elimination of microbiota-accessible carbohydrates (MACs) from the diet results in thinner mucus, increased proximity of microbes to the epithelium, and heightened expression of inflammatory markers.

Bottom line:   EAT LOTS OF DIFFERENT WHOLE FOOD BASED FIBER to feed your microbiome.  DON’T COUNT ON THE FIBER ADDED IN PROCESSED FOODS OR THE SUPPLEMENTS YOU TAKE FOR THAT FIBER.

Best in Health thru Awareness,

Last updated: January 2, 2018 at 17:11 pm to fix a broken link to American Gut microbiome findings. 

Prior update Feb 17, 2017 added two sections to stress diversity of fiber is important:

1. It’s not just about eating more fiber, its important to eat variety, or diversity, of fiber.  

2. Most Americans eat little fiber, and most don’t even know to eat more. 

Prior update Nov 19, 2016 added Sonnenburg links (elimination of microbiota-accessible carbohydrates (MACs) from the diet results in thinner mucus, increased proximity of microbes to the epithelium, and heightened expression of inflammatory markers.)