The Miracle of Mucus?

When giving a talk, Elaine Gottschall, the author of Breaking the Vicious Cycle (the book that lays out the specifics, and science, of the Specific Carbohydrate Diet) used to show 3 slides, illustrating the incredible mucus production in intestines afflicted with inflammatory bowel disease.


This is the villi of a healthy intestine.


This is one with inflammatory bowel disease.  You can see that the villi are flattened and that goopy looking white stuff stretched across them is excess mucus.

with mucus.jpg

Many of us saw massive amounts of mucus coming out with our children’s stool a couple of months after starting the diet.  I remember that, at the time, we wondered if it weren’t a sign of healing…the body evacuating excess mucus? I still don’t know the answer.  Elaine hypothesized that the mucus production was the result of excess acids (i.e. short-chain fatty acids, for example) being produced by bacterial overgrowth, damaging the lining of the intestines:  “Bacterial growth in the small intestine appears to destroy the enzymes on the intestinal cell surface preventing carbohydrate digestion and absorption and making carbohydrates available for further fermentation.  it as at this point that production of excessive mucus may be triggered as a self-defense mechanism whereby the intestinal tract attempts to ‘lubricate’ itself against the mechanical and chemical injury caused by the microbial toxins, acids, and the presence of incompletely digested and unabsorbed carbohydrates.”[i]  (Think what would happen if, for example, you inhaled pepper into your nose.) But after reading the following article, over the weekend, you do have to wonder if there’s not even more to it.

“More than 200 square meters of our bodies — including the digestive tract, lungs, and urinary tract — are lined with mucus. In recent years, scientists have found some evidence that mucus is not just a physical barrier that traps bacteria and viruses, but it can also disarm pathogens and prevent them from causing infections.”[ii]

It turns out that mucus is “…a therapeutic gold mine…”  And apparently, humans produce liters of it every day.

Work just published out of MIT shows that glycans (of which there are hundreds of kinds), complex sugar molecules in mucus, appear to have a profound effect on the gut bacteria.  They appear to have the ability to neutralize the negative effects of pathogenic organisms, including halting bacterial communication and the formation of biofilms.  (You can read more about these in slimy hotbeds of bacteria and yeast here.)

“A slimy, hydrated mucus gel lines all wet epithelia in the human body, including the eyes, lungs, and gastrointestinal and urogenital tracts. Mucus forms the first line of defense while housing trillions of microorganisms that constitute the microbiota. Rarely do these microorganisms cause infections in healthy mucus, suggesting that mechanisms exist in the mucus layer that regulate virulence.”[iii]

Researchers exposed a pathogenic bacterium, Pseudomonas aeruginosa, to glycans and found that doing so made the bacteria harmless.  In fact, these scientists have also found that treating burn wounds infected with this pathogen with glycans reduced the infection.  Essentially, the glycans prevent the bacteria from establishing an infection.

Going forward, these scientists plan to look at the anti-bacterial properties of individual glycans, as well as looking at these sugars’ ability to negate the harmful effects of other pathogens, including Streptococcus and the yeast, Candida albicans.  Thus far, work on the former looks promising.  Someday, these may be used in lieu of antibiotics, which has tremendous advantages.  As one of these researchers says, “What we find here is that nature has evolved the ability to disarm difficult microbes, instead of killing them. This would not only help limit selective pressure for developing resistance, because they are not under pressure to find ways to survive, but it should also help create and maintain a diverse microbiome…”  It also looks likely that glycans play a major role in determining the composition of the bacterial (and possibly fungal) microbiome.  They may actually act as a source of nutrients for probiotic bacteria.  (After all, structurally, glycans are very similar to the oligosaccharides found in breast milk.)

Back to the excess mucus then found in Elaine’s diseased intestines:  I really do wonder if the body doesn’t produce extra mucus when faced with infection, at least in part, as an anti-pathogen mechanism?  That excess mucus may be protective in more ways than we currently understand.  I don’t know the answer.  But how exciting a proposition is the idea of harnessing the power of our own, natural antibiotics to treat infection and benefit the composition of the microbiome?!


[i] Gottschall, E. Breaking the Vicious Cycle.  1994. Kirkton Press: Baltimore, Ontario.


[iii] Kelsey M. Wheeler, Gerardo Cárcamo-Oyarce, Bradley S. Turner, Sheri Dellos-Nolan, Julia Y. Co, Sylvain Lehoux, Richard D. Cummings, Daniel J. Wozniak & Katharina Ribbeck. Mucin glycans attenuate the virulence of Pseudomonas aeruginosa in infection. Nature Microbiology, 2019 DOI: 10.1038/s41564-019-0581-8

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