No doubt: insight into the best ways to manage our prebiotic fiber intake is an evolving process.

Those of you who have been following these Wheat Belly conversations for some time recognize that we view bowel flora, the 3-pound or so collection of trillions of microorganisms concentrated in the colon, as a crucial player in human health. The species composition and relative numbers within each species play roles in bowel health, regularity, protection from colorectal cancer, even yielding metabolites that have metabolic impact on our bodies and modulate, for instance, blood insulin, blood sugar, triglycerides, and blood pressure. There is even discussion about a “gut-brain” axis that reflects the profound effect bowel flora metabolites exert on brain health.

And we all begin with various degrees of dysbiosis given our prior exposure to the many factors in modern life that modify species composition, such as occasional antibiotics, antibiotic residues in meats and dairy, chlorinated/fluoridated water, wheat and grain consumption, and many others. To help you understand the process we go through to re-establish something close to healthy bowel flora, we view our bowel flora as a garden. The “seeds” are high-potency probiotic preparations with as high a CFU count and as many species believed to be healthy as possible, while the “water” and “fertilizer” are prebiotic fibers that nourish healthy species and promote their proliferation. Wisdom in both areas, probiotics and prebiotic fibers, are evolving rapidly. We could, of course, wait 20 years until much of the science has been clarified. But I don’t think that is necessary—we can start now. Even with the limited knowledge we now have, it is still possible to obtain substantial health benefits by adopting a rational program for bowel flora cultivation.

In particular, there are some important lessons surrounding prebiotic fibers that you should know about to help maximize your chances of success:

  • Vary your choice of prebiotics–Over and over again, the studies point towards species diversity—having many different bacterial species—is a marker for health. Slender people have greater species diversity than obese people. Non-diabetics have greater species diversity than diabetics. People without cancer have greater species diversity than people with cancer. Primitive people unexposed to modern disruptive factors have greater species diversity than modern people. Because different prebiotics feed different species, we cultivate species diversity by varying our choices of prebiotic fibers: inulin one day, GOS the next, a raw white potato the next, a green unripe banana, the next, etc.
  • Avoid carbohydrate overexposure—Raw unmodified potato starch and green banana flour are, unfortunately, dehydrated at a temperature of 140 degrees F, a temperature high enough to degrade nearly 50% of fibers into sugars. While such flours do indeed contain prebiotic fibers, they also expose you to lots of sugars. So use these very sparingly, e.g., no more than 1-2 tablespoons.
  • Heat—While heat degrades the fibers in potatoes and bananas, inulin (longer chain) and FOS (shorter chain) are the exceptions and are more resistant to degradation from heat. Inulin and FOS even remain intact at the temperature of boiling water (212 degrees F, 100 degrees C), meaning you can add it to coffee or tea without converting to sugar. (For this reason, you can use the Wheat-Free Market Virtue Prebiotic Mix made with inulin to create hot cocoa without degrading the fibers.) Just be careful in very acidic liquids, such as lemon juice or vinegar, as an acid pH can, more than heat, break fibers down into sugar.
  • Aim for a total daily prebiotic fiber intake of 20 grams per day—The average person obtains between 5 and 8 grams per day, 3-4 grams of which are from grains. Measurable benefits begin at 8 grams per day. We banish all grains from our diets, leaving us with a small deficit. We therefore compensate and increase to the ideal daily intake of 20 grams per day for full benefit. At the start, however, aim for no more than 10 grams per day to avoid excessive bloating, abdominal discomfort, or emotional effects, as prebiotics can also cause proliferation of unhealthy microbial species. (This is why we also begin the Wheat Belly process with a high-potency probiotic to encourage proliferation of healthy species.)
  • If you follow all of the above, but are still experiencing excessive bloating, discomfort, or emotional effects—stop the prebiotic fibers while continuing the probiotic. This means you start with a substantial dysbiosis and prebiotic fibers are causing unhealthy species to proliferate. An initial simple workaround: continue the probiotic for another 4 weeks, then re-attempt the prebiotic fiber. This often works, allowing more time for the probiotic alone to cause shifts in bowel flora composition. If even this 4-week probiotic-only period does not allow you to resume the prebiotic, then it is time to seek help. You will likely have to either engage in a FODMAPS program for several months to essentially starve bowel flora and/or antibiotics to wipe the bowel flora “slate” clean.

I attended a recent conference on the emerging science behind bowel flora. But, even here among the experts, there was no agreement—actually very little discussion—about the nuts and bolts on how to best cultivate healthy bowel flora. So we are left with using logic and applying existing knowledge to crafting a program. But, given the thousands of people engaged in this process, it is working with reductions in blood pressure, blood sugar, better bowel habits, and improved mental/emotional states.