I only gave the paper a brief read and some things stood out to me. First, the participants were recruited by
Autism Society of Greater Phoenix which is part of the umbrella organisation of
Autism Society of America. Both are heavily invested in a vaccine causation and still cling to the belief that thimerosal causes autism. They also heavily promote "biomed" for "treating" autism which includes chelation based upon a challenge test which is not acceptable.
The authors also used some dubious labs for their metrics, DoctorsData and Vitamin Diagnostics which cater to so called 'autism doctors' and perform non-standardised tests which are then used to justify rather awful treatments. The authors also got pretty creative with their statistical analyses not only with some of their tests but also their own strata of statistically significant.
The results were kind of all over the place and they didn't control at all for medications and diets that the children were on. What they found for some metrics is not conclusive for causality but rather correlative which could very well be explained by neurobehaviours as many ASD children have sensory and texture issues that not only affect their dietary preferences but also effect inappropriate ingestion of non-food materials.
The study was funded in part by Autism Research Institute which also believes that autism is caused by vaccines and can be "cured". They support doctors who are not qualified in ASDs to treat ASD children. They have a lot of money behind them and there is no excuse for them to be funding such crap studies when they have actually funded some good ones.
Este