The high prevalence of autism spectrum disorder (ASD) has been a concern for parents, educators and others for a long time. Buie (2013) stated that according to the Centers for Disease Control and Prevention 1 in 88 children in the United States have the disorder. It has been difficult to find effective interventions to manage the disorder. One of the interventions that have been suggested is the implementation of gluten free diets. In attempting to examine the effectiveness of this intervention some of the issues to be considered include the origin of gluten free diet as a therapy and the research evidence that has been gathered to support the use of this diet in controlling ASD.
Although gastrointestinal (GI) problems have commonly been described in children with autism, these problems are also seen generally in children so that the evidence of the high occurrence in children is not consistent (Buie, 2013). Celiac disease or gluten sensitivity has been genetically linked and there is speculation, but not enough research evidence, about gluten contributing to autism and other neurobiological disorders (Buie, 2013). One of the theories for the cause of autism is the Opioid-Excess Theory which explains that there is insufficient enzymatic activity in persons with autism, coupled with an increase in gastrointestinal permeability. This means the peptides formed from the breakdown of proteins in dairy and cereals are not converted to amino acids and they leak into the blood stream and attach to opioid neuro-receptors in the brain and cause behavioral problems (Mulloy, Lang, O’Reilly, Sigafoos, Lancioni & Rispoli, 2009). This opioid- excess theory was originally proposed by Panksepp in 1979 who suggested that removing casein and gluten from the diet of a child with ASD should prevent any increase in the levels of opioids produced by the body and blocking them from reaching the brain so lead to improved behavior ( Hurwitz, 2013). This theory has been the basis for implementing a gluten free diet for people with ASD. Research has been done in order to examine the effectiveness of this as an intervention for managing ASD.
The research studies reported by Buie (2013) showed mixed results. In one study a group of children with autism from a residential school were put on a gluten free diet and there was improvement in the amount of peptide in their urine, suggesting possibility of further benefits in decreasing the behavioral issues. In anther study with four children there was no behavioral improvement. When milk and gluten were removed from the diet of some children in another study there was developmental progress. Buie (2009) concluded that there was not enough evidence to support a gluten free diet for children with autism. However this was not the only review of the research. Mulloy et al (2009) did a review of all the available studies in which a casein free gluten free diet (CFGF) was used to treat ASD. They found 14 studies with a total of 188 participants ranging in age from 2- 17 years. In these studies the time during which the diet was implemented ranged from four days to four years , with an average time of 10 months. Again the results were mixed. In the studies that reported negative results the diets were implemented for shorter times, 4 days – 3 months. In the studies that reported positive results the diets were implemented for up to four years. These authors also concluded that the studies did not sufficiently support the CFGF diet as an effective intervention for children with autism.
The review of the research was continued by Hurwitz (2013) who examined the studies done after Mulloy et al’s review. Hurwitz (2013) suggested that of the 14 studies reviewed by Mulloy et al only three were rigorous enough. She found five studies that focused on CFGF diet with randomized groups of children with ASD and that compared diet with no-diet conditions. The participants in these studies also ranged in age from 2-16 years. All the studies measured the effects of the diet on ASD severity, language, or development. In this review the results were also mixed. Three studies did not support the diet as the children did not improve on any of the language, attention, activity level, sleep or bowel habits. One study reported differences in some of the behavior measures and in the other study the parents reported improvements in the autistic behavior after one year of the diet. Hurwitz (2013) points out that managing the diets at home for long periods of time could be difficult for parents and difficulty to determine whether it is the diet that is causing the behavior changes could affect the results. Another suggestion is that there may have been a placebo effect as the parents consider the diet a big effort and so they want results. This may also account for why the diet is so popular even though the research evidence is not conclusive about the effectiveness of the diet in controlling ASD. Parents are anxious to try any intervention. According to Hurwitz “Implementing GFCF diets may give parents a sense of empowerment and a feeling that they are doing something proactively that might benefit their children” (p.15).
Further investigations with parents reported improvements in speech and communication skills, decreases in hyperactive behavior, improvement in the child’s ability to focus, and decrease in sleep problems (Pennesi & Klein, 2012). These researchers examined 448 children with ASD and the diet. The parents completed an online survey over a 5-month period to report on improvements in ASD behavior, physiological symptoms, and social behavior. The improvements were observed when the parents were strict with the diets, not when partially eliminating foods. It was also important to maintain the diet outside of the home and to implement the diet for more than six months. The children who benefited most from the diet were the children who had GI problems (constipation and diarrhea) and those who had food and other allergies.
It is difficult to conclude whether the diet is effective or not since the research so far has not been conclusive, and there have only been a small number of studies. Most of the positive results seem to be come from parents’ reports and not from empirical evidence gathered by the researchers themselves. It seems from some of the studies that there are some benefits to the diet, but only under certain circumstances. Further research is needed to deepen the understanding of the effects of a gluten free diet on the symptoms of ASD, and to provide more information on the different ways that the diet can help.
- Buie, T. (2013). The relationship of autism and gluten. Clinical Therapeutics,35(5), 578-583. Hurwitz, S. (2013). The gluten-free-casein-free diet and autism: Limited return on family investment. Journal of Early Intervention, 35 (1), 3-19.
- Mulloy, A., Lang, R., O’Reilly, M., Sigafoos, J., Lancioni, G., & Rispoli, M. (2010). Gluten-free and casein-free diets in the treatment of autism spectrum disorders: a systematic review. Research in Autism Spectrum Disorders,4 (3), 328-339.
- Pennesi, C. M., & Klein, L. C. (2012). Effectiveness of the gluten-free, casein-free diet for children diagnosed with autism spectrum disorder: based on parental report. Nutritional Neuroscience, 15 (2), 85-91.