How Fiber can alter our Gut Flora

Here’s Karl Seddon’s latest video. Have a look, 16 minutes of good explanations of how fiber effects your gut. And keep in mind as you watch, when you are doing a short-term Potato Hack, you are getting massive amounts of some of the same fibers that Karl discusses in the video.

If your gut does not tolerate an all-potato diet, or you’ve had problems when taking fiber or RS supplements…you really need to watch this!

If you’d like to buy Karl’s Elixa Probiotics, or to sign up for new content notifications, please click here. I hear there’s a new Elixa PREbiotic fiber mix coming soon!

Elixa Website and Store

For your viewing pleasure:

33 Comments on “How Fiber can alter our Gut Flora”

  1. Teddy February 10, 2017 at 10:02 am #

    Another great episode. Karl makes it very easy to picture how things work. I just wish he had listed some of the ‘selective’ fibers – i.e. the ones that the good guys thrive on more than the pathogens. I understand that most fibers feed all microbes – good and bad. However, using the word ‘most’ implies that there are exceptions, right? Which are they? I assume Karl is working on combining all the exceptions in Tribal.


    • Tim Steele February 10, 2017 at 10:32 am #

      I feel for Karl, trying to make this subject easy to understand. “Fiber” is such a massive topic. I think to answer your question, one needs to examine each fiber for each prebiotic potential, and then see how it effects an individual.

      There are many well-known prebiotics, meaning they have proven capability to cause friendly bacteria to flourish, and pathogens to diminish. When the term “prebiotic” was coined, only inulin and trans-GOS (used in baby formula) were included. Then others started making the list: FOS, RS, Larch AG, pectin, etc… The list changes based on new research into lesser known fibers and man-made fibers.

      Fibers that are not considered prebiotics are cellulose, dextrins, lignan, sugar alcohols, etc.

      Actually, here’s a great 2014paper explaining all this and the changing nature:


    • kbseddon February 13, 2017 at 11:27 am #

      Thanks Teddy! The nice feedback is much appreciated 🙂
      If I had to name a single fiber to take for trying to correct problems, I would name inulin. (preferably people would simply experiment with different fibers one by one)
      If I had to name the fiber I think we received to our guts in highest quantity from a natural diet I would say cooked starch, uncooked starch, and inulin (with a fructan chain length range from long chain all the way to FOS [>10]).
      -Karl (Elixa)


      • kbseddon February 13, 2017 at 11:29 am #

        I.e. a fructan of chain length less than 10 monosaccharide units.


      • Debbie February 13, 2017 at 2:17 pm #

        Thanks, Karl.

        Liked by 1 person

  2. Wilbur February 10, 2017 at 11:13 am #

    This is a great video. Karl has a great gift of being smart and being able to explain things very well. I wish he’d write a book. I’m so frustrated that there really isn’t (to my knowledge) a good book on this.

    Tim – I’ve been reading a new book “Life at the Speed of Light” by Craig Venter, the guy who led the sequencing of the human genome and invented shotgun sequencing.

    Besides the fascinating overarching tale of creating synthetic life (which scares the sh*t out of me), the book goes into some detail about how bacteria have such extraordinary capabilities that might ruin a study. I’m finding it suspenseful, horrifying, and very informative. Just I. Case you are interested.


    • Tim Steele February 10, 2017 at 2:43 pm #

      You read the best books! I’m half way through Mann’s 1491 ( at the moment.


    • kbseddon February 13, 2017 at 11:34 am #

      Hi Wilbur,
      Really glad to hear you like the videos!
      Your comments on here, vegpharm, and FTA are always the ones I pore over in detail.
      Your results (and intuition) regarding prebiotic blends -and the greater topic of the microbiota- is very intriguing; so I always pay attention to what you post.
      -Karl (Elixa)


      • Wilbur February 13, 2017 at 1:24 pm #

        Karl –

        Your kind comments make me very happy! I’ve pointed several people new to the gut to your videos.

        I’m still doing the same things in terms of my fiber drink. But something new that I’m doing is tea. Or herbal teas, or whatever you call it. Same logic. I’ve got at least 50 different blends, and I usually drink t per day. In addition to the typical teas (green, black, rooibos, etc.), lots of flowers (hibiscus, chamomile, jasmine), spices, baobab leaves, dandelion leaves, and on and on. Also truly fermented tea, not just oxidized.

        Today I made my own blend of garlic, onion, reishi mushroom, turmeric, ginger, holy basil, cracked Malabar peppercorn, Szechuan peppercorn, and holy basil. It was really good!

        I’m finding that I have “intuition” about teas just like fiber. I think it’s a great way to get more variety of prebiotics in the gut. . It’s weird being giddy about tea.


  3. Debbie February 10, 2017 at 2:29 pm #

    Tim, which ingredient in Gut Garden is the expensive, unusual one? Because I’m having success with Gut Garden, while also taking Inulin and Hi Maize. But I’m fairly sure the Gut Garden is making a difference. Still experimenting with dosages!


    • Tim Steele February 10, 2017 at 2:41 pm #

      Gut Garden has Acaia and arabinogalactin, these are pretty expensive to buy and show great benefits in medical research. Also has inulin and potato starch, also two great fibers. A very ingenious blend, I believe.


      • Debbie February 13, 2017 at 2:15 pm #

        So, it’s the arabinogalactin that is new for me. Just ordered two more jars of Gut Garden 🙂 Thanks!


  4. Stephen February 11, 2017 at 6:18 am #

    About a year ago, if I ate more than 2lb of potato I’d get nauseous, diarrhea, etc.. Just a teaspoon or two of Inulin would tear me up. Now I can eat 5lbs of rs3 prepared potatoes, and 3 tablespoons of Inulin a day(plus other fibers) and have no issues.


    • Tim Steele February 11, 2017 at 6:49 am #

      That’s great to hear! Most people are unwilling to push through the discomfort, but the ones that do usually benefit from it.


    • Martin Groeneveld February 11, 2017 at 10:40 am #

      Stephen, I am in a somewhat similar position to where you were a year ago. Would you mind sharing how you gained your tolerance for prebiotics please?

      I follow Perfect Health Diet and I eat cooked & cooled rice and potatoes everyday, plus I supplement with 2 tablespoons of potato starch and a teaspoon of baobab powder (pectin) per day. I tolerate this well and experience no gut discomfort.

      However if I supplement with inulin (just a teaspoon) or if I eat beans or jerusalem artichoke I get massive bloating and wind and if I persist with this for a few days I get diarrhea.

      I am unsure of the best way to proceed from here. Should I:
      (a) supplement with small amounts of inulin and trust that over time the good bugs will thrive more than the bad bugs and eventually I will be able to tolerate larger amounts of inulin.
      (b) keep inulin out of my diet and starve the bad bugs which eat it. This relies on trusting that the good bugs which eat inulin can also survive on RS2, RS3 and pectin.

      Any advice would be appreciated.


      • Tim Steele February 11, 2017 at 10:47 am #

        Hi, Martin – If I may interject, almost every study involving humans and fibers has a segment of “non-responders.” This is why I always recommend people shop around and find a starch or blended product that works for them. Nothing out there will work for everybody, all the time. Your current fiber/RS regimen sounds fantastic. If I remember correctly, the non-responders in inulin trials were even higher than for RS and other fibers. Probably because inulin is not eaten by many people unless they specifically look for it, whereas, RS is present in lots of foods we all eat, ie. potatoes, rice, bread, potato chips, etc.


      • Stephen February 13, 2017 at 8:29 am #

        I started with the small dose of Inulin and gradually built up. I also supplement with acacia powder (Heathers Tummy Fiber). I think that the acacia made the Inulin easier to tolerate. I read that the acacia ferments slowly and that it also slows down the fermentation of other fibers as well. I know that Inulin ferments rapidly. I think that taking the acacia along with the Inulin helped reduce the harsh effects of the Inulin. Now, I can take Inulin by itself with no acacia, and I feel fine. I still use 2-3 tablespoons/ day of Heathers because I think it’s good stuff


  5. Martin Groeneveld February 11, 2017 at 11:25 am #

    Thanks for the response Tim. Just to clarify, does “non-responder” mean NO response to consuming the fiber, or any response other than a positive one?
    I ask because I definitely response to inulin, it is just that it is a negative response (bloating, wind, discomfort).

    If I understood your reply correctly, you recommend I follow plan (b), i.e. keep inulin out of my diet and stick to RS2, RS3 and pectin which I know do not cause me discomfort.


    • Tim Steele February 11, 2017 at 12:07 pm #

      If I remember right, almost everyone in that study had some negative side-effects initially, which subsided after a week or so. The “non-responders” were the ones that could not tolerate inulin at any dose. The “responders” were able to tolerate something like 20g at a serving, and the non-responders had bad symptoms with as little as 1g. I’ll see if I can find the paper.


  6. Martin Groeneveld February 11, 2017 at 1:17 pm #

    Thanks Tim!


  7. Jo tB February 13, 2017 at 12:04 pm #

    Hi Martin, with a name like Groeneveld, I would assume that you live in Holland or Belgium. But that may not be the case. However, I can let you know that most fibers can be purchased from Dutch internet companies. The only one I have not been able to find is green banana flour. So I generally use half a green banana (bakbanaan) as a prebiotic instead.


  8. Curtisy Briggs February 13, 2017 at 1:45 pm #

    Tim–I wondered if you had seen this recent article about effects of RS apart from the microbiome. Interesting!


  9. Stephen March 1, 2017 at 6:32 pm #

    My gut has gotten used to a decent amount of prebiotic fibers over the past year. I have to take 50mg of doxycycline for the next few weeks to help with a chronic eye chalazion/style. I’ll keep taking my Wilber inspired fiber mix but was wondering if this antibiotic will cause me to loose the gut gains I’ve made. My dr. said this low dose won’t mess with the gut bugs. Any recommendations?


    • Tim Steele March 1, 2017 at 7:01 pm #

      You are in a good place, Stephen. Antibiotics are no problem if you have a healthy gut to begin with, and eat lots of fiber during and after the course. The death blow to a gut is a fiber-poor diet and lots of antibiotics.

      I hope your eye gets better quickly!


  10. Dan April 23, 2017 at 3:13 pm #

    I just went to re-order a tub of Thorne Fibermend (blend of Larch, Prune powder, Pectin, Green Tea Phytosomers) and noticed they changed the formula. The new version omits rice bran. I can only speculate, fear of arsenic questions (?). Yikes this blend is expensive $42 a tub of less than 12 ounces.


  11. Dan April 24, 2017 at 3:00 pm #

    I went looking for a book or additional sources and found out there is a whole professional organizational devoted to dietary fiber:


    • Tim Steele April 24, 2017 at 3:07 pm #

      Pretty cool find, Dan. I just looked at the agenda of the fiber symposium: Big-time food industry sponsored. This is Big Food at it’s finest, attempting to create new policies and definitions that support their financial endeavors. It makes me feel good about my grass-roots effort to spread the word on real-food fibers and RS.


      • Dan April 24, 2017 at 3:15 pm #

        It also mentions sponsorship by the National Institutes of Health and the Dept of Agriculture…so I am curious how they can receive funding from both public and private sectors? makes me uneasy to think there is not at least an arms length relationship between government and industry in this regard…ugh.


        • Tim Steele April 24, 2017 at 4:18 pm #

          Ingredion, for instance. Makers of Hi-Maize. They would not even talk to me regarding a study to compare Hi-Maize to Potato Starch, but you can bet they will spend millions lobbying congress to get Hi-Maize included in wording on bills related to fiber.

          Session 1 of the symposium: “From a US standpoint, the ‘future of fiber’ starts with the new definition FDA is adopting. Fibers are now intact/intrinsic or extracted/synthetic. If isolated/synthetic, the fiber must have proven health benefits. ”

          This is 100% related to food manufacturers being able to put the cheapest substance in a snack and labeling it “high in fiber.” This subject is in desperate need of overhaul, presently the definition of fiber is very vague, sawdust and wheat chaff qualify as fiber.

          Proving the health benefits of fiber will be the contentious part of all this. If a company that makes an isolated fiber can show that this fiber causes bifidobacteria to grow in a Petri dish, will that be enough? Fiber is really only as good as the gut it is going into, right? Any fiber could be bad or good depending on the bacteria in a person’s gut.

          I think it’s great that smart people are studying this and working with the government to get better definitions of fiber, but the discussion will be steered by Big Food with a focus on fiber in processed foods.


  12. Dan April 24, 2017 at 3:21 pm #

    I also notice it’s free to academics and government employees who register before April 30th 🙂 could be interesting to see what they have to say….


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