As parents have long reported, many children with autism experience severe gastrointestinal (GI) problems and the associated discomfort can worsen behavior. Researchers, in turn, have found a strong link between (GI) symptoms and autism severity. Some experts have even proposed that toxins produced by abnormal gut bacteria may trigger or worsen autism in some children.
Now scientists at Columbia and Harvard universities report that the GI activity of children with autism differs from that of other children in two key ways:
1) Their intestinal cells show abnormalities in how they break down and transport carbohydrates, and
2) Their intestines are home to abnormal amounts of certain digestive bacteria. (Bacteria play an important role in normal digestion. But abnormal levels of certain bacteria have been associated with digestive problems and intestinal inflammation.)
The two findings are likely related, the researchers propose. Alterations in how intestinal cells break down carbohydrates can affect the amount and type of nutrients that these cells provide to intestinal bacteria. This, in turn, may alter the makeup of the intestine’s normal community of digestive bacteria--with ill results.
“The findings are consistent with other research suggesting that autism may be a system-wide disorder, says study co-author Mady Hornig, M.D., director of translational Research at Columbia University’s Center for Infection and Immunity. The study is available through the online scientific journal PLOS-One.
The findings may also explain why many parents of children with autism report that special diets and probiotics (nutritional supplements containing “good” bacteria) improve not only their children’s digestion but also their behavior, the researchers note. However, they caution that further study is needed as their findings were based on tissue samples from a relatively small number of children (fifteen with autism and seven with typical development).
Autism Speaks co-funded the study along with the National Institutes of Health, Google.org and the Department of Defense. Recognizing that GI problems affect many children and adolescents with autism, Autism Speaks recently granted a major Suzanne and Bob Wright Trailblazer Award for research into the biological mechanisms of GI disorders in ASD. The research will include clinical testing of a new probiotic therapy that has shown promise in restoring GI function.
“GI problems are a common and distressing concern for many children and adolescents with ASD and their families,” explains Autism Speaks Chief Science Officer Geraldine Dawson, Ph.D. “These conditions are not only a strain on the health of the children affected, GI problems can seriously interfere with their ability to participate in and benefit from activities of daily life, education and therapeutic activities.”