SIBO, brain fog and probiotics

When it comes to nutrition, yes you can get too much of a good thing.  Excess intake of many Health Halo nutrients and foods can create adverse — even dangerous — effects.  Water and certain fat soluble vitamins are some examples.   I came across a pretty fascinating study recently that examined the connection between probiotic use and incidence of Small Intestinal Bacterial Overgrowth (SIBO) that made me wonder if probiotics should be added to the list.

If you haven’t heard of SIBO, here’s a very brief explanation:

  • SIBO refers to excessive growth of bacteria in the small intestine, where significant populations of bacteria should not be found.  Bacteria belong in the large intestines.
  • Why are the bacteria in the small intestines?  Certain medical conditions can increase risk for this, such as intestinal surgeries.  But other more common causes include low stomach acid and motility problems in the stomach and intestines.
  • Normally, stomach acid can inactivate bacteria, but we produce less and less stomach acid as we age.  And plenty of people take antacids for heart burn.
  • When the muscles of the digestive tract don’t push the food along quickly enough, it sits around in the small intestines, encouraging bacteria to grow.  Normally if you wait 3-4 hours between meals, your stomach starts to growl, which is a sign that strong muscle contractions are pushing food and bacteria out, in a sort of house cleaning process ahead of your next meal.  If you’re constantly eating and never experience actual hunger, those strong muscle contractions don’t happen.  Generally slow digestive tract motility can be caused by other diseases or genetics.
  • When you eat, those bacteria start fermenting the food in the small intestines, leading to symptoms like bloating, gas, abdominal dissension, diarrhea, pain, malabsorption and inflammation of the small intestine lining.  While these may not be life threatening, they can seriously impact quality of life.
  • SIBO can be diagnosed by specialized breath tests or samples of stomach and intestine contents taken during an endoscopic procedure.  Different antibiotics are used for treatment, depending on which types of bacteria are present.

The study in question looked at a different potential problem from SIBO: brain fog.  We’ve all heard the term “brain fog”, which can mean pretty much anything a person wants, including difficulty concentrating, poor memory, confusion and impaired judgment.  Of course, these symptoms can be caused by plenty of other things, like fatigue, alcohol, hangovers, medications, depression, cancer chemo, pregnancy, hypothyroidism and dementias.   The researchers noted that a condition called D-lactic acidosis is associated with brain fog symptoms.  D-lactic acidosis is usually attributed to a medical condition called short-bowel syndrome, common with people who have had part of the small intestines removed during surgery.  In this case, bacteria that produce D-lactic acid, like lactobacillus and bifidobacteria, proliferate in the remaining small intestine and ferment carbohydrates, producing D-lactic acid, which is absorbed and can then adversely impact brain function.

How do we get from a rare medical condition like short bowel syndrome to SIBO and brain fog?  The theory is that the SIBO-causing bacteria are producing D-lactic acid.  Furthermore, SIBO may be aggravated by probiotics, which put large doses of lactobacillus and bifidobacteria right into the small intestine.

The study compared people who complained of SIBO symptoms and brain fog to people who did not complain of any such symptoms.  They were all otherwise healthy.  The study looked at an extensive number of variables, including reported symptoms as well as breath tests, samples from the small intestine taken by endoscopic exam, and metabolic testing for lactic acidosis.   Several of the subjects were also evaluated for intestinal motility using a wireless motility capsule that tracked intestinal transit.  This was a really thorough study of all the possible known issues related to SIBO.

Almost everyone in the Brain Fog group complained of the common SIBO symptoms listed above.  Most of them tested positive for SIBO and had D-lactic acidosis.   By comparison, only a very few people in the non-Brain Fog control group tested positive for SIBO, although they did not report any symptoms.

All of the people in the Brain Fog group were taking probiotics.  Some were taking 2 or 3 different kinds.  Many were also eating probiotic foods like yogurt.  Only a couple of the non-brain-fog control group used probiotics.  Subjects who tested positive for SIBO were treated with antibiotics and asked to stop using probiotic supplements.  At follow up, 85% of the treated subjects reported the brain fog went away, along with most other symptoms.

So what are we to make of this?  Probiotic supplements haven’t been around that long, and have not been evaluated for either effectiveness or side effects.  Another recent article expressed concern about the lack of attention to potential side effects in studies of probiotics and gut microbes.  It’s as if the assumption by pretty much everyone is that Probiotic = Good/Healthy, so why look for problems?  End of discussion.  Perhaps not.

It’s easy to see how this could spiral out of control.  A person has distressing abdominal symptoms like bloating, gas, etc and thinks “Oh, probiotics will fix that” and starts taking random probiotic supplements.  Symptoms may not improve; the person concludes they aren’t talking enough probiotics.  He or she starts taking more, or a different brand.  The possibility that the probiotic supplement is making things worse is never, ever considered.

What to do?

I’m not suggesting all probiotics cause SIBO in all people.  If you’re using a probiotic supplement and all is well, then fine.

If you experience disagreeable digestive symptoms and a probiotic supplement doesn’t seem to be helping, then maybe you should listen to your body rather than to marketing hype.  A gastroenterologist can evaluate your symptoms, and many do the breath testing that can pinpoint whether you have SIBO and need treatment.  Remember, the typical symptoms of SIBO, as well as so-called brain fog can be caused by many other medical conditions, so don’t self-diagnose.

My preference for probiotics is always food over supplements.  Fermented foods have been around for centuries.  But if you think any particular fermented food is causing you problems, you may be right.  Just because a food has a Health Halo doesn’t mean it’s a good choice for you.  You may like yogurt, but not kefir.  Or kombucha may work for you, but not yogurt.

Here are some final tips:

  1. The bacteria related to SIBO ferment carbohydrates.  If your meals are typically heavy on simple carbs like breads or sugary foods and drinks, that could exacerbate the problem.  Better to eat high fiber meals with moderate amounts of protein and healthy fats and little added sugar.
  2. Constant eating prevents your digestive system from ‘cleaning house’.  Hunger is a sign that your stomach and intestine muscles are contracting and flushing out residue, including bacteria.  Let your digestive system do it’s job.
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