Originally posted by Dr. Davis on 2018-08-04
on the Wheat Belly Blog, sourced from and currently found at: Infinite Health Blog.
PCM forum Index of WB Blog articles.

Do you get brain fog with probiotics?

We may now have an explanation for the people who experience brain fog with probiotic use.

We already know that intolerance to prebiotic fibers within the first 60 minutes of ingestion strongly suggests that small intestinal bacterial overgrowth, SIBO, is present. If you experience excessive gas, bloating, abdominal discomfort, or diarrhea within the first hour of consuming, say, inulin, a raw white potato, or legumes, it is virtually certain that you have SIBO that must be addressed if you desire full recovery of health. Recall that uncorrected SIBO can account for fibromyalgia, IBS, restless leg syndrome, psoriasis, and marked long-term potential for autoimmune diseases, diverticular disease, and various forms of neurological impairment and colon cancer. It is absolutely worth pursuing and correcting.

But people who add a probiotic or fermented foods like yogurt or kefir who experience brain fog—cloudy thinking, difficulty concentrating, fatigue, forgetfulness—have a condition called D-lactic acidosis, an excess of a poorly-metabolized form of lactic acid (as compared to the more common and more readily metabolized L-lactic acid). Brain fog is typically accompanied by bloating, abdominal discomfort and distension, and gas after meals.

A recent study suggests that this constellation of symptoms is due to the action of Lactobacillus and Bifidobacteria species present in common probiotic preparations and fermented foods, microbes that are generally beneficial to humans, that convert sugars and carbohydrates to D-lactic acid. Higher blood levels of D-lactic acid can therefore be measured. In other words, the ordinarily beneficial probiotic species work against you.

The tangle gets worse: People who experience these symptoms with probiotic usage also appear to have SIBO. Recall that SIBO is proving to be a condition that is epidemic, likely on a par with the epidemics of type 2 diabetes and pre-diabetes. Extrapolating from existing data, it is likely that something like 60 to 100 million Americans have SIBO. SIBO may explain, for instance, why there has been a substantial uptick in colon cancer among 20 and 30-somethings.

The sequence goes like this: You have SIBO with invading Enterobacteriaceae Gram-negative organisms like E. coli and Shigella inhabiting the stomach, duodenum, jejunum, and ileum, as well as the colon where they are supposed to be confined. You have been taking a probiotic and/or fermented foods containing Lactobacillus or Bifidobacteria that, along with SIBO organisms, colonize the upper gastrointestinal tract. After meals, you experience mind fog and gastrointestinal upset due to an increase in blood levels of D-lactic acid produced by Lactobacillus and Bifidobacteria. In other words, in this situation probiotics add to the problem and do not solve it.

Intolerance to probiotics, fermented foods, and prebiotic fibers therefore serves as a therapeutic test that can uncover SIBO. You should not ignore this. Gram negative Enterobacteriaceae that live in the upper gastrointestinal tract are highly inflammatory, as they are both directly toxic to the intestinal lining and add to increased intestinal permeability, allowing the breakdown product, lipopolysaccharide, from the cell walls of these organisms, to enter the bloodstream. Even in minute quantities, bacterial lipopolysaccharide inflames the body and adds to autoimmune inflammation, skin inflammation,. brain inflammation, etc. This exceptionally common condition called SIBO is a 30-foot long chronic intestinal infection that will take you down in health unless you do something about it.

Solution: Should you experience these effects that persist after you initiate the Wheat Belly lifestyle—wheat/grain elimination, net carb limitation, vitamin D restoration, magnesium and iodine supplementation, fish oil, probiotic/fermented foods/prebiotics—stop the probiotic and prebiotics and start learning about SIBO. Efforts to identify and correct your SIBO are the next step, something we consider and discuss at length in the Undoctored program, especially the Undoctored Inner Circle. It would be nice if you could consult with your doctor and he/she would help you get the job done. Sadly, most physicians will have no idea what you are talking about, dismiss your question, tell you that you shouldn’t worry about it, or refer you to a gastroenterologist who performs and upper endoscopy and colonoscopy then declares you healthy because you don’t have stomach ulcers or colon cancer, while nobody addresses the SIBO.

So, more often than not, you are on your own with managing SIBO. Once SIBO is corrected, resume the probiotic, fermented foods, and probiotics to repopulate your colon with desired bacterial species and help beat back SIBO recurrences.