Can probiotics prevent ADHD and autism?

Can probiotics prevent ADHD and autism?

A new study from Finland is the first to show that probiotic supplementation early in life may be an effective way to reduce the rising tide of brain disorders in children.

There is a growing amount of medical research indicating that alterations in the type of bacteria that live in our gastrointestinal tract can influence brain function, mood and overall mental health. A new study from Finland is the first to show that probiotic supplementation early in life may be an effective way to reduce the rising tide of brain disorders in children, such as attention deficit hyperactivity disorder and autism spectrum disorders.

GI disturbances are very common in children with brain disorders such as attention deficit hyperactivity disorder and autism spectrum disorders including Asperger’s syndrome. A number of mechanisms have been suggested linking these brain disorders, as well as some of the common digestive disturbances these kids experience, to alterations in the gut bacteria.

One novel theory is that lower levels of beneficial gut bacteria such as Lactobacillus and Bifidobacteria in children with ASD and ADHD leads to an increase in toxin-producing bacteria such as Clostridium species. In addition to this possibility, an altered gut flora also leads to increased gut permeability. Several studies have shown that the integrity of the intestinal lining is compromised in both ADHD and ASD. Increased gut permeability could lead to the absorption of microbial byproducts, as well as partially digested food-derived compounds that may affect brain cell function directly or lead to immune responses that could also affect brain cells. Since probiotics can also improve the gut barrier, they may provide additional benefits in ADHD and ASD through this mechanism as well.

Furthermore, since approximately 80 percent of the immune system resides in and around the intestinal lining, probiotics may also favorably affect the immune system to reduce the GI inflammation often observed in children with ADHD and ASD.

Adding additional support for this line of thinking is a recent study in healthy women which showed that supplementation with a mixture of probiotic bacteria had significant effects on brain regions that control central processing of emotion and sensation, indicating that the probiotic bacteria themselves may be capable of exerting beneficial effects directly on brain function and mood.

New study produces provocative results

To test the hypothesis that probiotic supplementation may protect against the development of ADHD and AS, researchers in Finland looked closer at a study that was originally designed to test the effect of early supplementation with a probiotic in infancy on the later development of eczema. The mothers of 159 children were recruited and randomized in a double-blind, placebo-controlled manner to receive 10 billion colony-forming units of Lactobacillus rhamnosus or placebo daily for four  weeks before expected delivery. After delivery, the capsule contents were given either to the children, or continuously to the mothers, if breast-feeding, for six months.

To evaluate for a possible link between probiotic supplementation and ADHD or AS, 75 of these children were evaluated by an experienced child psychiatrist or neurologist not involved in the study or follow-up, and the children were randomized and blinded so as not to produce any study bias. Results showed that ADHD or AS was diagnosed in six out of 35 (17.1 percent) of the children in the placebo group, and none (out of 40) in the probiotic group. The probability value of this occurring was 0.008, indicating that it was not due to chance but rather to a clear effect.

Because fecal samples were stored, the researchers were able to analyze the children for gut bacteria during their first six months of life. What the researchers found was that the numbers of Bifidobacterium species bacteria in feces during the first 6 months of life was lower in children with ADHD and AS compared to the healthy children.

The researchers concluded: “Probiotic supplementation early in life may reduce the risk of neuropsychiatric disorder development later in childhood possible by mechanisms not limited to gut microbiota composition.”

When I read this study, my immediate response was WOW. Not because the results were unexpected, but rather my surprise that someone actually studied the possibility that probiotic supplementation may offer significant protection against the development of AS and ADHD.

What are the takeaways from this study? Alterations in gut bacteria and/or GI function/integrity may be a major factor in the development of childhood behavioral disorders. I strongly encourage all expecting mothers to supplement their diets with a high quality probiotic supplement, continue with that supplement while breastfeeding, and give their infants a probiotic supplement when they are no longer being breastfed.


Pärtty A, Kalliomäki M, Wacklin P, Salminen S, Isolauri E. A possible link between early probiotic intervention and the risk of neuropsychiatric disorders later in childhood: a randomized trial. Pediatr Res. 2015 Mar 11. doi: 10.1038/pr.2015.51.

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