SIBO is typically viewed as a source for abdominal symptoms such as bloating, excessive gas, and diarrhea. And that is indeed true. But did you know that phenomena such as food intolerances, joint pain, neurological deterioration, and weight gain, conditions far outside the gastrointestinal tract, can also be blamed on SIBO?

For those of you new to this conversation, small intestinal bacterial overgrowth, SIBO, is a situation generated by factors such as over-exposure to antibiotics that have killed off many beneficial microbial species in the colon that allows unhealthy fecal microbial species to proliferate. Over-proliferated fecal species are then able to ascend up into the 24-feet of small intestine, amounting to trillions of microbes living where they do not belong. The 24-feet of small intestine is poorly-equipped to deal with trillions of fecal microbes, as the small intestine has a single-layer mucus barrier, unlike the colon’s two-layer mucus barrier better suited to housing fecal microbes. The small intestine is also, by design, more permeable, as this is where we are meant to absorb nutrients such as vitamins, minerals, and amino acids. Trillions of fecal microbes therefore live and die in the small intestine. When they die, they shed their components, some of which are toxic. One toxin, in particular, so-called lipopolysaccharide endotoxin, or LPS endotoxin, is able to exit the small intestine and enter the bloodstream: endotoxemia. Endotoxemia therefore “exports” the effects of invading fecal microbes in the small intestine all throughout the body. This explains how microbes dwelling in the GI tract can be experienced as effects on the brain, skin, thyroid, heart, liver, uterus, knees and hips, and other organs and body sites. Yes, a disrupted gastrointestinal (GI) microbiome can cause or worsen gastrointestinal conditions such as irritable bowel syndrome, ulcerative colitis, or Crohn’s disease. It can also lead to other GI conditions such as diverticular disease and colon cancer. But a disrupted GI microbiome, SIBO, and endotoxemia can also underlie numerous other non-intestinal modern health conditions.

It means that outside of the GI tract, SIBO and endotoxemia can be blamed for:

  • Food intolerances—presumptively due to the increased intestinal permeability of SIBO superimposed on an already-permeable small intestine. Intolerances to FODMAPs (fibers and sugars), fructose, legumes, nuts, IgG-triggering foods, nightshades and others do not represent something wrong with food; they represent something wrong with your GI microbiome. Food avoidance can reduce symptoms, but it does not address the underlying cause: SIBO.
  • Weight gain and obesity—because endotoxemia is a major driver of insulin resistance, the process underlying weight gain, especially in the abdomen.
  • Pre-diabetes and type 2 diabetes—While the doctor prescribes metformin, GLP-1 agonists like Ozempic, or insulin injections, he/she ignores a major underlying cause, SIBO and endotoxemia. Their ignorance or indifference therefore resigns you to these pharmaceutical strategies, while also allowing many of the other consequences of uncorrected SIBO and endotoxemia to develop over time.
  • Restless leg syndrome—a massive disrupter of sleep and cause of daytime fatigue.
  • Fibromyalgia—This painful condition is treated with awful drugs such as Cymbalta or Lyrica that have debilitating side-effects such as fatigue, mind fog, and massive weight gain, prescribed indiscriminately while never asking whether a disrupted GI microbiome might be the underlying driving factor.
  • Autoimmune conditions—The increased intestinal permeability of SIBO leads to the process of “molecular mimicry,” causing your immune system to wage an attack against various organs, “tricked” by food or microbial breakdown products in the GI tract. It could manifest as Hashimoto’s thyroiditis, rheumatoid arthritis, autoimmune hepatitis or autoimmune pancreatitis, psoriasis, alopecia or dozens of other conditions resulting from a misguided immune response.
  •  Neurodegenerative conditions—Parkinson’s disease, Lou Gehrig’s disease (amyotrophic lateral sclerosis), multiple sclerosis, cognitive impairment and dementia can all have their origins in a disrupted GI microbiome. I had a recent conversation with BiotiQuest probiotic founder, Martha Carlin, who has devoted her life to finding solutions to Parkinson’s disease since her husband was diagnosed with this condition at age 44. She tells me that, over and over again, she has seen that people with Parkinson’s disease have a history of previously engaging in long-distance exercise such as running marathons, carb-loading prior to and during the event with pasta, “energy” bars and drinks. Carb loading is extremely disruptive over health and the GI microbiome, sufficient to cause, for instance, both SIBO and SIFO (small intestinal fungal overgrowth) while also significantly increasing intestinal permeability even further in the 24 hours after engaging in such an event. In other words, the practice of extreme exercise coupled with carb loading and transient exaggerated increased intestinal permeability may set the person up for SIBO and endotoxemia. Not proof, but interesting nonetheless. (And another example of how some people have managed to convert something healthy—exercise—into a destructive health practice.)
  • Mental/emotional struggles—Add depression, suicidal ideation, anxiety, violence, anger, intolerance, selfishness, narcissism and other mental/emotional struggles to the list of human behaviors triggered by SIBO and endotoxemia. Of course, the medical system has a drug for every condition, all while ignoring the flood of endotoxin that drives or worsens these conditions. Note, for instance, the series of German studies in which non-depressed volunteers were injected intravenously with LPS endotoxin and became depressed almost immediately, coupled with MRI evidence showing all the hallmarks of clinical depression. The reverse can also be true, i.e., mental/emotional distress can cause SIBO and endotoxemia, making the situation worse, as demonstrated, for instance, in this study in which marital distress was associated with greater endotoxemia (accepting that we may have a “chicken and egg” dilemma). In short, SIBO and endotoxemia bring out the worst in people.
  • Accelerated aging—An acceleration of skin aging, deterioration of joint cartilage and arthritis, sarcopenia (loss of muscle), osteopenia and osteoporosis (bone thinning and fractures), frailty, loss of cognitive abilities, increased risk for heart disease and stroke are all due in large part to SIBO and endotoxemia. Get facial filler injections, prosthetic knees and hips, engage in cognitive exercises, or take a statin cholesterol drug and you have done nothing to address the disrupted GI microbiome and endotoxemia driving these phenomena.

That’s just a partial list of diseases caused or worsened by the GI microbiome. Add in the conditions that are caused by “local” microbiome disruptions, such as that in the sinuses, mouth, throat, airway, uterus and vagina, prostate gland, skin and other body locales and you begin to appreciate just how profoundly body microbes influence the human condition. A disrupted vaginal microbiome, for example, can be responsible for repeated bouts of vaginal candidiasis, miscarriages, and premature labor.

A return to something closer to a healthy GI microbiome begins with removing factors disrupting the situation, such as minimizing exposure to antibiotics, banning all sources of herbicides and pesticides, minimizing exposure to heavy metals like mercury and cadmium, filtered drinking water to remove chlorine and fluoride, avoiding food additives such as preservatives, emulsifiers, and synthetic sweeteners. We then restore keystone, or foundational, microbial species lost by nearly all modern people, species such as Lactobacillus reuteri and Lactobacillus gasseri that 1) colonize the small intestine, and 2) produce bacteriocins, natural antibiotics effective against fecal microbial species. We also make a habit of including plenty of fermented foods in our daily routines, foods such as fermented pickles and sauerkraut, kimchi, kefir, and others that introduce microbial species, such as Leuconostoc mesenteroides and Pediococcus pentosaceus that are transient inhabitants of the GI tract but “cross-feed” metabolites to bloom beneficial resident species such as Faecalibacterium prausnitzii and Akkermansia muciniphila. In my view, antibiotics are rarely needed, yet you can have impressive effects on many aspects of health, including reducing or eradicating your risk for all of the above scary diseases.

For more on this issue of the many faces of SIBO, give the latest episode of my Defiant Health podcast a listen or see my Super Gut book that details the problems and provides detailed solutions.