A topic mentioned in class one day was if a special diet could reduce the effects of autism in someone, which made me curious on the topic. Autism spectrum disorder (ASD) and autism are terms that are used to represent “a group of complex disorders of brain development” (Autismspeaks). The U.S. Centers for Disease Control and Prevention found that around 1 in 68 American children fall on the autism spectrum, and ultimately it “affects over 3 million individuals in the U.S. and tens of millions worldwide” (Autismspeaks). There is no explanation to the increasing prevalence in autism, but different therapies and intervention has proven to help the effects of autism. Besides turning to therapy, some people approach autisms effects with what a person on the spectrum eats.
Numerous studies have been done to investigate if having a selective diet is helpful to a person with autism. One was a preliminary double blind clinical trial done in 2006. Previously, there had been testimonials that supported the efficacy of the gluten-free and casein-free diet, and there were numerous parental and teacher reports, saying after an autistic child was placed on a restricted diet, they were “cured” of their autism. Before this study was done, there was “insufficient empirical data supporting these claims,” meaning these “conclusions” and ideas that a special diet would help people with Autism, were only based on theory or pure logic (source 2). This study’s credible evidence to prove this idea came at the perfect time.
This study had a total of 15 children, average age being 7 years, with ASD. 12 of them were boys, and 3 of them were girls. The sample size and boy to girl ratio are concerning. The fact that there are only 15 children being tested could skew the results. In addition, more than half of the small sample are boys. Boys and girls could react to a restricted diet differently, and therefore should be represented equally to avoid any negative effects on the results. Besides this, the study does take note of the sample’s race and any major medical problems. One child was Asian, and the rest were Caucasian. Although they acknowledge their race, they fail to look at a diverse group of children, since only one child is a different race than the others. This could affect the results, and make it questionable if they can conclude anything for children in general, and not just Caucasian children. Any child who had celiac disease or physical or sensory-impairments were excluded from the study, thus not skewing the results. The children completed a 12-week protocol.
There were many instruments for measuring the progress of the children. Childhood Autism Rating Scale (CARS) and Autism Diagnostic Interview-Revised (ADI-R) were used to describe the subjects, or judge autistic features. These are very detailed tests, which should have contributed to the accuracy in this study. CARS assessment followed their behavior with relationships with others, imitation, emotional expression, body use, peculiarities and many others. CARS validity “has been assessed as good under various conditions” (source 2). ADI-R “is a semi structured interview for caregivers of individuals with autism,” which studies “impairment in reciprocal social interaction, communication, and repetitive behaviors and stereotyped patterns” (source 2). The researchers also took into consideration the dependent variables, and used CARS, Urinary Peptide Levels (UPL), Ecological Communication Orientation (ECO) Language Sampling Summary, and in-home observations to do that.
Only the data manager and dietician knew who received a placebo diet and who received a gluten free diet. Making the trial a double-blind placebo trial can lead to more accurate results. All the participants received meals from the GCRC’s Metabolic Kitchen during the 12-week period. Ultimately, the design of this study was to compare a regular diet and the gluten-free and casein-free diet “in terms of autism symptoms as measured by” the instruments listed above (source 2). This let researchers see their “social initiating, social responding, intelligible words spoken, and non-speech vocalizations” (source 2). Looking at the results of the study, “group analysis results indicated no significant differences with CARS and ECOS, or behavioral frequencies grouped data for urinary peptide levels of gluten and casein” (source 2). In other words, there weren’t significant differences in the instruments to measure progress, including CARS, ECOS, and urinary peptide levels.
So, why does the double-blind placebo trial show a lack of results, while testimonials swear diet decreased autistic traits? One reason might be the unreliability of anecdotes. Although the parents of an autistic child may have seen a decrease in autistic traits at one point, this could have been caused by a confounding variable, not just the change to a gluten-free diet. For example, it is important to note any changes in physical activity, change in environment around the child, and anything else that could have an affect on an autistic child’s behavior. On the other hand, parents could claim seeing a decrease in autistic behavior when, in fact, it did not actually happen. They could have so strongly wanted to see a change that they convinced themselves there was a change. Anecdotes are not reliable enough to draw conclusions on. The observation could be a one-time change that was due to chance, so by conducting a study, the results could be more accurate, although still having the ability to be effected by chance. Since the anecdotes only happened one time, there is not evidence that if they tried it again, they would be successful.
The double blind clinical trial is not flawless either. The conclusion they made that there was “no significant differences with CARS and ECOS, or behavioral frequencies grouped data for urinary peptide levels of gluten and casein” could be a false negative. This would mean that they conclude there was no effect from a gluten free diet, while there actually is one. There have been many other studies done to try to prove the same thing, one being done in the University of Sunderland in the United Kingdom. By using Meta analyses, researchers could possibly figure out if this is actually a false negative or not, and how the studies differed procedurally and with its results. Lastly, there could be a null hypothesis. Although researches thought they saw results, it could have been no significant changes in the children’s behavior. This is especially possible for parents who tested a gluten free diet at home.
This argument hit close to home, because my neighbor was diagnosed with autism when he was about 2. My neighbor was born in 2003, and he went on a gluten-free diet about 4 years later, which would only be about a year after the first trial was conducted. The fact that his parents went off this, like you said, poorly conducted study, shows a couple of things. First of all, it shows that when these types of studies are published, they cause people to make dramatic changes in their lifestyles that are not necessary. Another thing that this proves is that parents are willing to do anything to help cure their child, even if that means listening to an unreliable study. Eventually, my neighbor was taken off the diet, and although he does have autism, it is not very severe and he will grow up to live a relatively normal life. Did his gluten-free diet help with this? According to your blog, it did not. Perhaps it was a third variable, or perhaps by chance he was blessed with only being slightly autistic to begin with.