Student research

by
Karyn Matterson
Bachelor of Nutrition and Dietetics, University of Wollongong
Supervisors: Anne Swain, Velencia Soutter, Robert Loblay
November 2003

Full Text - PDF (340 KB)

Background: Some current beliefs with regard to dietary issues in children with ASD submit that these children are more prone to gastrointestinal challenges as compared to children without ASD. Implementation of gluten-and casein-free diets have been consistent in clinical improvements seen in children suffering from ASD and gastrointestinal problems. This study was conducted to see whether children with ASD are more prone to gastrointestinal problems as compared to a population of children without ASD and to compare the patterns in two specific opioid peptides present in their urines and bloods, which are purported to affect the behaviour in children with ASD.

Method: 24 hr urine specimens were collected from subpopulations of children with and without ASD. Creatinine was measured by standard clinical method based on the Jaffe reaction, prior to urine being analysed by reverse phase column HPLC. The reference peptides used were ß-casomorphine bovine and gluten exorphine A5. 4mls of blood were collected from populations of children with and without ASD. Coeliac diagnostic screening was ordered to assess the presence of IgG and IgA and antigliadin autoantibodies in order to assess the prevalence of any gastrointestinal pathology between groups. A 4 day diet record was kept over the time the urine and blood specimens were collected, in order to validate consumption of food versus the excretion of wastes, of particular interest being the opioid peptides previously mentioned.

Results: The creatinine results suggested that there was non-compliance by the subjects. The trace patterns for the HPLC showed hyperpeptiduria, particularly in the region where gluten is eluted, for subjects with ASD and some subjects in the control group, with little significance where casein is eluted. The blood results showed normal results in a population for prevalence of HLA DQ2 genes, which indicate a genetic propensity toward coeliac disease.

Discussion: It is not possible to ascertain whether an opioid peptide effect exists in this population, as in general, everyone excretes peptides and the excretory pattern is highly individual. A relationship between wheat and milk in diet and excretion of peptides could not be found. A comparison of HPLC patterns shows similarity between those subjects with ASD and those subjects with positive HLA DQ2 screening tests, which may indicate that gluten may contribute to gastrointestinal sensitivities. It is essential that food intolerance issues are explored further, as most gluten containing foods contain salicylates, and some contain amines and glutamate as well as the salicylates, which are all known to cause reactions in food chemical sensitive individuals. The clinical improvement previously reported with dietary interventions such as gluten-and casein-free diets may be attributed to reducing the load of naturally occurring chemicals in the diet, hence behaviour and gastrointestinal problems decreasing.