last time, I am going to attempt to cover what was said in the consensus report was published last week in Pediatrics. The report contained 23 statements that covered a wide range of topics relating to gastrointestinal disorders and autism.
I am going to give a general summary of what the report said with some minimal comments. If you have access to the report itself, I highly recommend that you read it. So, without further ado, the report says ...
People with autism who have GI symptoms deserve the same treatment for their symptoms as other patients would receive. Gastrointestinal conditions that are common in "typical" individuals are just as common in people with autism. However, the problem is that people with autism may have a hard time communicating their symptoms effectively and there is a lack of guidelines for how to evaluate someone with an impaired ability to communicate. Further compounding the problem is the fact that gastrointestinal disorders in people with autism can cause or aggravate other seemingly unrelated problems, problems such as sleep disturbances, irritability, vocal or motor tics, tantrums, aggression, and self injurious behavior.
While these may seem like trivial statements, I believe that they are squarely aimed at children's doctors who have grown accustomed to automatically dismissing parental reports of GI symptoms. The statements are an admonishment to remember that children with autism can have GI problems too, and that these symptoms need to be taken seriously. Ahem, moving along...
It is not well understood how common gastrointestinal abnormalities are in autism. There are studies that show that these abnormalities are very common in people with autism while others say that these abnormalities are no more common than in the general population. Unfortunately, most of the research that has been done in this area is flawed and that makes it hard to draw any reliable conclusions.
Even still, based on the evidence that is available today, the preponderance of the data suggest that gastrointestinal symptoms are more common in people with autism than in "typical" people. More research is needed to properly address this question.
But while it is possible that gastrointestinal symptoms are more common in autism, there is no evidence establishing a gastrointestinal disturbance specific to people with autism. Specifically, this point refers to Wakefield's "autistic entercolitis" - there simply is not enough direct evidence to support the idea that it exists.
This should not come as a surprise to anyone. I would suggest that the reason for this has more to do with politics than with science. Given the stigma attached to Wakefield's work, I can understand why other scientists are reluctant to take up this question. Which is really tragic, because the main thrust of Wakefield's work was that there is a gastrointestinal disturbance that contributes to autism, not that the MMR vaccine causes autism. Continuing with the paper ...
The panel found that there is limited evidence of abnormal gastrointestinal permeability (leaky gut) in people with autism. While some studies have found that this can be an issue in a subset of children, the available evidence is not sufficient to confirm that a abnormal permeability is an issue or that it contributes to autism. This is yet another area that needs more research.
Just to interject, the idea of a "leaky gut" goes to the heart of how some special diets, such as the gluten-free casein-free diet, are thought to work. It also goes to the heart of why the existing research on dietary interventions in autism are badly flawed. The idea is that some, but not all, people with autism have GI issues and a subset of this group would benefit from dietary treatments. Yet the research that has been done has not attempted to locate the subset that would benefit from the diet and has just lumped everyone with autism into one big bucket. And as most people know, people with autism are nothing if not diverse.
So far I have covered the controversial parts of the report, next time I will continue with some of the more common sense things the report had to say.