Mucilaginous Fiber: The Good, the Bad, and the Gooey

February 15, 2016 in Categories: , , by

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Cup_of_Chia_Seed_PuddingYou might not know what mucilage is just by the name, but chances are, you’ve seen it in action! Chia seeds, flaxseeds, and agar agar all contain a type of vicious, soluble fiber called mucilage that swells up and becomes gelatinous and gooey when it makes contact with water.  Many paleo recipes call for high-mucilage foods to create certain jelly-like textures (think chia seed pudding, for example!). And, the unique properties of this fiber have resulted in mucilaginous foods being touted for their health benefits, especially when it comes to healing gut conditions.

It’s true that fiber does some amazing things for or bodies (you can read more about that in my multi-part Fiber Manifesto here, here, here, here, and here!), and mucilaginous fiber is no exception. But, there are some situations where mucilage may actually aggravate certain health problems and be worth avoiding (at least temporarily!). Understanding the wide spectrum of health effects from this fiber can help us decide how much of it to incorporate into our diets!

All About Mucilage

arabinose_sugar_in_mucilageOn a molecular level, mucilage is rich in simple sugars such as xylose, arabinose, rhamnose, galactose, glucose, and sometimes mannose and fucose. (Different sources of mucilage—like leaves vs. roots vs. seeds—have different simple sugar compositions, but typically, these are the sugars that dominate!) For plants, mucilage comes in pretty handy. It can help barricade injuries from pathogens by forming a gelatinous layer on the wound site, helps plants develop a relationship with soil-dwelling life forms like fungus, serves as a barometer to check water loss, aids in germination, and helps facilitate seed dispersal.

Nearly all plants produce some amount of mucilage, but a few plants are extremely rich in this fiber! The most mucilaginous plants tend to be succulents (like aloe) and cacti, some types of seaweed, certain seeds, and roots. More specifically, the highest-mucilage foods are:

  • Brown_Flax_SeedsFlaxseeds
  • Chia seeds
  • Psyllium
  • Aloe vera
  • Kelp
  • Okra
  • Figs
  • Agar agar (algae)
  • Cactus pads (AKA nopales—a great wild edible!)
  • Fenugreek
  • Marshmallow root (the stuff traditionally used to make marshmallows!)
  • Slippery elm
  • Licorice root
  • Plantain
  • Cassava
  • Fermented soybeans, natto (although soybeans aren’t inherently rich in mucilage, mucilage is produced by bacteria during the fermentation process for natto)


(Keep in mind, the mucilage in plant foods is not the same substance that causes bone broth to become jiggly in the fridge! That honor goes to the gelatin, the water-soluble protein derived from cartilage in bones, tendons, and other animal tissues.)

The Good

Mucilage has been long been praised for its role in human health, and rightfully so! Tons of research points to beneficial and therapeutic activity for this unique fiber. Mucilage from cactus pads, for example, has been shown to act as a prebiotic, enhancing the growth of lactobacilli, increasing short-chain fatty acid production, and reducing the population of harmful species of enterococci, enterobacteria, staphylococci, and clostridia. Mucilage-rich psyllium is often used to stimulate normal bowel function and absorb excess water (making it useful for both constipation and mild diarrhea). Some mucilage-rich herbs can suppress the blood sugar response to a glucose meal, due to a delay in glucose absorption from the intestinal membrane. And, the addition of mucilage to a calorie-reduced diet has been shown to cause greater weight loss and greater reductions in triglyceride and total cholesterol levels than diet alone (possibly due to reduced intestinal absorption of bile acids).

Not surprisingly, mucilaginous extracts have been used medicinally for a variety of purposes. However, many of them operate as immune modulators or stimulators, which brings us to…

The Bad

Although the immune-stimulating effects of mucilage may be beneficial in some contexts, in other cases, this can actually be detrimental!

For instance, some types of mucilage specifically stimulate either the Th1 immune response (like flaxseed) or the Th2 immune response (like the mucilage in natto, or fermented soybeans). If someone has an autoimmune disease and is already Th1 or Th2 dominant (see The Paleo Approach), stimulating the wrong pathway can aggravate the Th1/Th2 imbalance instead of helping to correct it, resulting in a worsening of autoimmune symptoms. Plus, regulating the immune system is far more complex than simply stimulating the more suppressed pathway, as used to be standard in Th1/Th2 balancing protocols, now thoroughly debunked.

If you have an immune system that is not regulating itself well, as is the case in all autoimmune diseases but also any chronic illness since inflammation is a consequence of an immune system that isn’t modulating itself properly, then stimulating inflammatory immune pathways is not likely to do you any favors. When it comes to mucilage, individual responses are likely to vary greatly since the composition of your gut microbiome, exactly how your immune system is dysregulated, nutrient status, stress level, sleep debt, and exactly how much you eat of which mucilage are all inputs into the equation.

Clostridium-Difficile-1024x682And, mucilage can potentially be harmful in other ways as well. Although mucilage is only partially degraded by gut microbes, when it does become hydrolyzed in our intestines, its simple sugars get liberated and become potential food for bacteria—and not just the beneficial strains! A number of pathogenic microbes can chow down on the xylose, arabinose, rhamnose, galactose, glucose, mannose, and/or fucose contained in mucilage, especially if the gut is already compromised. Some of those bacteria species include:

  • Clostridium difficile, which can eat the galactose, mannose, and glucose liberated from mucilage. When imbalanced, it can cause Clostridium difficile colitis, a severe infection that can range from diarrhea to potentially deadly colon inflammation (and even a hole forming in the intestines!).
  • Escherichia coli (E. coli), which can eat the glucose, arabinose, and xylose liberated from mucilage. Certain strains of coli are famous for causing foodborne illness due to producing a toxin called Shiga toxin, which can lead to vomiting, fever, severe stomach cramps, and bloody diarrhea. About 5-10% of people with this type of E. coli infection develop hemolytic uremic syndrome (HUS), which can potentially be life-threatening.
  • Staphylococcus aureus, which can eat the galactose liberated from mucilage. This is a major opportunistic pathogen that produces a variety of toxins (both enterotoxins and cytotoxins) and can cause nausea, vomiting, diarrhea, cramps, fever, and loss of appetite. And, it can alter the overall structure of the gut microbiome and reduce the production of beneficial short-chain fatty acids (SCFAs).

And that’s just to name a few!

Basically, what this means is that for certain forms of gut dysbiosis, mucilage might actually feed the wrong bacteria and consequently worsen gut health instead of improving it. For example, someone with an overgrowth of C. difficile (and an under-abundance of beneficial resident bacteria to compete with it!) might find that mucilage encourages the C. difficile to flourish and cause infection. This could especially be an issue after a hospital visit or long-term antibiotic treatment that kills of intestinal bacteria that usually keep C. difficile in check.

There’s no evidence that eating a diet rich in mucilages can cause gut dysbiosis if you’re starting out with a healthy diverse gut microbiome. But, this may explain why so many people report worsening of gastrointestinal symptoms or symptoms of autoimmune disease when they eat foods like psyllium and chia.

So… Is it Yay or Nay for Mucilage?

Okra_slicedGiven the wide range of positive health effects from mucilaginous foods, mucilage isn’t a definite no-no for a healthy, nutrient-dense diet! But, it’s worth noting that despite the glowing endorsements for this fiber, we may need to reduce or eliminate high-mucilage foods while we build an optimal gut microbiome or address a dysfunctional and overstimulated immune system. In most cases, these situations will be temporary, and we can eventually enjoy okra gumbo or cassava fries without worry!


Anderson E & Fireman M. “The mucilage from psyllium seed, plantago psyllium, L.” J. Biol. Chem. 1935;109:437-442.

Anderson E. & Lowe HJ. “The composition of flaxseed mucilage.” J. Biol. Chem. 1947;168:289-297.

Bacic A, et al. “Structural Analysis of Secreted Root Slime from Maize (Zea mays L.).” Plant Physiol. 1986 Mar;80(3):771-7.

Clifford SC, et al. “Mucilages and polysaccharides in Ziziphus species (Rhamnaceae): localization, composition and physiological roles during drought-stress.” J Exp Bot. 2002 Jan;53(366):131-8.

Dumitriu S. “Polymeric Biomaterials, Revised and Expanded.” 2nd ed. 2001: CRC Press. Page 485.

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Enzi G, et al. “Effect of a hydrophilic mucilage in the treatment of obese patients.” Pharmatherapeutica. 1980;2(7):421-8.

Frati Munari AC, et al. “Lowering glycemic index of food by acarbose and Plantago psyllium mucilage.” Arch Med Res. 1998 Summer;29(2):137-41.

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Guevara-Arauza JC, et al. “Prebiotic effect of mucilage and pectic-derived oligosaccharides from nopal (Opuntia ficus-indica).” Food Science and Biotechnology. 2012 Aug;21(4):997-1003.

Innami S, et al. “Jew’s mellow leaves (Corchorus olitorius) suppress elevation of postprandial blood glucose levels in rats and humans.” Int J Vitam Nutr Res. 2005 Jan;75(1):39-46.

Jang CM, et al. “Effect of mucilage from yam on activation of lymphocytic immune cells.” Nutrition Research and Practice. 2007;1(2):94-99.

Köpke M, et al. “Clostridium difficile is an autotrophic bacterial pathogen.” PLoS One. 2013 Apr 23;8(4):e62157.

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Xu Q, et al. “Levan (beta-2, 6-fructan), a major fraction of fermented soybean mucilage, displays immunostimulating properties via Toll-like receptor 4 signalling: induction of interleukin-12 production and suppression of T-helper type 2 response and immunoglobulin E production.” Clin Exp Allergy. 2006 Jan;36(1):94-101.


Thanks Paleo Mom, perfect timing on this post! I just discovered last week that the chia seeds I’d been adding to the smoothies I have a couple of mornings a week were causing recent digestive upset. I have also noticed I need to watch my intake of cassava flour and keep it on a occasional basis, which makes sense since you list it as a mucilage-producing food. So it’s good to get the facts behind the story!

My first flare up came while I had be consuming chia seed and broccoli micro greens on a regular basis. There goes plantain mangu and chocoa plantain pudding!

So what can those of us with autoimmune diseases use/consume to heal our guts? My naturopath recommended chia seeds, slippery elm, and marshmallow root but those are all out because of the mucilage. DGL is ok for AIP you say, right? Anything else we can take for gut healing? I’ve been eating strict AIP plus low-fodmap for months and have been able to eliminate SIBO with herbal antimicrobials under my naturopath’s care, but I still have daily IBS symptoms and symptoms of leaky gut. Chicken bone broth is out on the low-fodmap diet because of the cartilage, so I drink/use beef bone broth. I’m following the AIP lifestyle modifications too. What else can we do?

Hello; Great article!! I have no thyroid due to cancer and have been struggling to get my levels corrected with NDT due to low stomach acid and nutrient deficiency. Would you say NO to the chia seeds for me, even though i have no noticeable side effects from them?

What would be a alternative to these fiber to add bulk to the stool? Being worse constipation since 3 months starting AIP… Take Magnesium (Oxy Powder, not on a regular basis), but would like to find the alternative in the food.

Thanks in advance for your help!

Now I’m wondering if these foods would aggravate my SIBO. I haven’t noticed any adverse reaction to ground flax seeds or chia seeds but I do know that I can’t tolerate plantains.

I just bought your book The Best of AIP. So what am I supposed to eat for breakfast?!!! This is very discouraging. I am trying to get a handle on this new elimination diet for Hashimoto’s which I don’t even know if I have yet (awaiting testing) but this is most challenging. And I’m a good cook who is open to new horizons…but this breakfast thing has really got me. Do YOU eat porkchops for breakfast? Please give me some suggestions. I feel like I’m drowning. I need to eat something substantial to get me through my morning eaten at home….I don’t have the leeway to stop and prepare something on the road…I am a traveling resource teacher who already carries tons of supplies. I sure don’t need to add more (food) stuff into my daily routine. But it appears that I will have too. Thanks for your time.

Don’t feel discouraged! It’s tough in the beginning but you will get the hang of it! It is tough for some people to get past having normal food for breakfast but I find it easiest if I just have leftovers from the night before and a piece of fruit. If you can get past the feeling of ” but it isn’t a breakfast food” then you have a lot more options. Even if you need a quick breakfast, you could always sautée some broccoli or cook some carrots! Eating this way also keeps you full longer because you are filling up with nutrient and protein dense foods. I hope you are doing better (I know this post is sort of old but I though I might as well try to help!) and I hope you are encouraged!

Fascinating and very helpful article. Have you found any articles that support theovergrowth of Candida albicans from consuming these fibres ?

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