Study: Could Probiotics Solve the Autism Puzzle?

Caltech researchers successfully use probiotics to treat autistic behavior in mice.


When journalist Moises Velasquez-Manoff wrote an article for the New York Times in August of last year positing that an immune disorder causes autism, reaction was mixed. On the one hand, his argument seemed so logical, so airtight: He linked the explosion in autism diagnoses to our hyper-clean world, so unlike the virus-and-bacteria-laden environment in which our ancestors lived (and ate). Moms with inflammatory diseases like celiac and rheumatoid arthritis have an increased risk of having autistic kids; so do those who are diagnosed with asthma or allergies in the second trimester and those who contract the flu or have infections. In Velasquez-Manoff’s view, the common culprit is the heightened inflammatory response in the moms, as their self-defense mechanisms, made dysfunctional by lack of practice in fighting microbes, kick into overdrive. (Incidentally, the incidence of asthma, also an inflammatory disease, has risen in parallel to that of autism.)

This theory was challenged by, among others, Michael Yudell of Drexel’s School of Public Health, who called it “reckless” at, and health blogger Emily Willingham, who accused the author of “squishy science.” Both Yudell and Willingham worried that pegging autism to a mom’s prenatal health would result in maternal guilt just as surely as the now-discredited “cold mother” causation once did.

Now comes word, via, that California Institute of Technology researchers have successfully alleviated autism-like behaviors in mice by giving them a probiotic bacterium, Bacteroides fragilis, used to treat gastrointestinal disorders in animals. Noting that autism and gastrointestinal issues often co-occur, Caltech biology professor Sarkis K. Mazmanian explains, “Traditional research has studied autism as a genetic disorder and a disorder of the brain, but our work shows that gut bacteria may contribute to ASD-like symptoms in ways that were previously unappreciated.” The researchers treated the mice, observed that their GI abnormalities were corrected, and noted that their behavior changed: They became more likely to communicate with other mice, were less anxious, and were less prone to repetitive digging. The researchers hope to begin human trials within the next year or two.

What’s most exciting about the findings, Caltech prof Paul H. Patterson notes, is that such a treatment for autism would be post-natal: “[T]he mother has already experienced the immune challenge, and as a result, the growing fetuses have already started down a different developmental path”—yet their behavioral issues could improve. Mazmanian adds, “I think our results may someday transform the way people view possible causes and potential treatments for autism.”