Enzyme supplements for autism. Do they work?

By Nestor Lopez-Duran PhD

I support the development of experimental treatments that are grounded on theory as long as practitioners and researchers do not jump the gun and present the treatment as a validated and effective method before there is compelling scientific evidence that the treatment works. For this reason, I’m always excited when I see well conducted research studies of experimental treatments, as these studies help clarify whether such experimental treatments are effective or not. This week I was particularly excited when I read one study examining the effectiveness of an alternative treatment for autism disorder. Specifically, a study conducted in Australia examined the effectiveness of an enzyme supplement for the treatment of children with an autism.

One theory about autism suggests that children with autism have abnormalities within their intestinal system.  This ‘leaky gut’ theory is based on the belief that the abdominal barrier in these children is defective and allows specific substances and toxins to leak into the child’s bloodstream. This has led to the development of a large industry that offers assistance to families in a variety of forms, from helping them create gluten free diets to providing supplements that help breakdown the proposed toxins. Some of these practices (i.e. gluten free) have been studied scientifically and unfortunately have been shown not to be as effective as their proponents claim. Other practices, such as enzyme supplementation, simply have not been properly examined.

The study examined the effects of Peptizyde, a dietary supplement, on the core symptoms of autism among 43 properly diagnosed children. This study was simple and elegant, and used a double blind randomized placebo controlled cross over methodology. In brief, this is how it worked: about 40 kids with autism were randomly assigned to either receive the enzyme supplement for 3 months or receive a placebo for 3 months. After the 3 months, the groups switched so that those receiving the placebo would now receive the supplement and those first receiving the supplement would now receive the placebo. The parents, teachers, and most of the study staff did not know who was receiving the placebo and who was receiving the supplement. Under this method all children received both the treatment and the placebo in 2 controlled sequences.

The authors then compared parental and teacher reports of symptoms during the time the children were taking the supplement as compared to the time the children were taking the placebo (Remember that the parents didnt know when their kids were taking the real supplement). If the supplement has an effect on autism symptoms or functioning, it is sensible to expect that parents would correctly identify changes when their children were taking the supplement but not when the children were taking the placebo.

The results:

No significant differences between the placebo and the supplement condition were noted on:

· Core symptoms as reported by parents

· Gastroinstestinal Symptoms

· Sleep Quality

· Social Engagement as reported by the therapist

· Vocabulary

· Sentence length

The only statistically significant effect was an increase in food variety during the supplement condition. That is, during the time the children were taking the supplement their parents rated them as having statistically significantly more food variety than during the time they were taking the placebo. However, the authors did not believe that this statistical finding was clinically significant because their mean scores of the two groups, 4.06 (placebo) and 4.42 (supplement), was small and clustered around the score 4, which means “no change”. I’m not sure I agree with that last conclusion because determining clinical significance is a complex process that is based on whether the difference in scores translate to meaningful differences in the day to day life of these children. In this case for example, clinical significance would mean that the difference between such scores, even if small, results in real changes in the childs diet, such as wanting to eat 3 more variety of vegetables, etc. That question of clinical significance can not be easily answered by simply examining the numeric difference of the scores and their location in the scale (near the ‘no change’ mark).

So unfortunately this study failed to provide evidence that enzyme supplementation is effective in the treatment of children with autism. I must mention however, that the study was conducted with a very small sample (less than 20 participants per group by the end of the study) which certainly impacted the researchers ability to find statistically significant differences between the groups. It would be reasonable for someone to argue that a larger study should be conducted before we can form a final conclusion regarding the effectiveness of this experimental intervention.

The reference:
Munasinghe, S., Oliff, C., Finn, J., & Wray, J. (2010). Digestive Enzyme Supplementation for Autism Spectrum Disorders: A Double-Blind Randomized Controlled Trial Journal of Autism and Developmental Disorders DOI: 10.1007/s10803-010-0974-2