Probiotics, an increasingly popular supplement, may cause debilitating brain fog in some individuals. The findings are detailed in a study newly published in Clinical and Translational Gastroenterology, which explains that some subjects had to quit their jobs due to mental cloudiness. D-lactic acid produced by the large bacteria colonies in the patients’ small intestines may have been the cause.
The research comes out of Augusta University’s Medical College of Georgia, where Digestive Health Clinical Research Center director Dr. Satish S.C. Rao and colleagues found that taking probiotics may have a negative effect on one’s ability to concentrate. Of the 30 patients detailed in a study, 22 experienced “brain fog,” namely trouble concentrating and confusion.
All 22 of those patients reported taking probiotics, in some cases taking several different varieties of probiotics. The study found that these patients had large bacteria colonies in their intestines as a result. When the lactobacillus “good bacteria” fermented the sugars in food consumed by the patients, a high level of D-lactic acid was produced.
In some patients, their level of D-lactic acid was two or three times beyond the normal amounts measured in a healthy patient. This is unfortunate, as D-lactic acid has a toxic — though temporary — effect on brain cells that causes symptoms normally referred to as “brain fog.”
The study reports that some patients experienced such severe brain fog for up to a several hours after eating that they had to quit their jobs. This isn’t to say that probiotics are “bad,” as they can be helpful in restoring gut bacteria after taking antibiotics. However, Rao cautions, “Probiotics should be treated as a drug, not as a food supplement.”