Research Supports Link between Autism and Digestive Disorders

Current research is reinforcing the theory that autism is linked to digestive disorders. Autism occurs at a frequency of 1 in 88 children in the United States and, of those children, 70% also experience some sort of gastrointestinal, or digestive, disorder. These disorders usually show up as chronic constipation or chronic diarrhea, as well as pain in the gut. The discomfort from digestive disorders may lead to some of the behaviors observed in children with autism.

One study was conducted by Pat Levitt, PhD, of the Saban Research Institute of Children’ Hospital of Los Angeles, and colleagues at the Keck School of Medicine at the University of Southern California and Vanderbilt University. This study, published in PLOS ONE, measured a blood chemical that indicates oxidative stress levels in children with autism who have gastrointestinal disturbances.

During oxidative stress, free radicals overcome the activity of antioxidants and can interfere with cell functions. This study measured the blood levels of IsoP, the primary indicator of oxidative stress, in four groups of children – those with only autism spectrum disorder, those with only gastrointestinal disorder, those with both autism spectrum disorder and gastrointestinal disorder, and those with neither disorder. IsoP levels were found to be elevated in all three clinical groups, with the most significant elevation in the group with both autism spectrum disorder and gastrointestinal disorder. The researchers hope that by understanding the impact of oxidative stress on the severity of autism symptoms, more individualized treatments for autism will be found.

Another study shows the link between a lack of beneficial bacteria in the gastrointestinal tract and autism. The study, conducted by researchers from Arizona State University’s Biodesign Institute, analyzed the differences in intestinal micro flora between children with autism and children with no symptoms of autism. The researchers analyzed the intestinal micro flora of 20 healthy children and 20 children with autism, all between the ages of 3 and 16. The samples were analyzed using a technique called pyrosequencing, which allows many DNA samples to be combined. The results showed a correlation between lower diversity of intestinal microbes and the presence of symptoms of autism.

The study also analyzed the presence of the microbe prevotella, which is believed to play a key role in the composition of a healthy intestinal tract. This analysis found that the bacteria prevotella corpi occurred in very low levels in the samples from the children with autism. The researchers plan to use these results as a guide for new treatment studies for autism. This study was also published in the journal PLOS ONE.

A third study, published in the journal Translational Psychiatry, identified a blood marker that shows a link between gut bacteria and autism in some children. This study tracked 213 children with autism and found that 17 percent of them had consistently abnormal levels of the blood marker, as well as evidence of abnormal cell energy function. This study provides more evidence that abnormal gut bacteria present in children with autism produce a waste product that is carried in the blood stream, affecting organ systems including the brain and, as a result, behavior.

The study from the journal Translational Psychiatry also indicates that no genetic factor caused the abnormal energy metabolism and instead points to an environmental trigger. The researchers stated that the study shows environmental factors could play a much larger role in the symptoms of autism than was previously thought.

In tomorrow’s article we will look at the nutritional deficiencies amongst children with autism and some recommended course of action.