Gluten-free, casein-free diet

 ( Autism Pseudoscience ) 

In the 1960s, Curtis Dohan speculated that the low incidence of schizophrenia in certain Pacific Islands societies was a result of a diet low in wheat and milk-based foods. Dohan proposed a Genetic disorder wherein individuals are incapable of completely Metabolism gluten and casein as a possible cause for schizophrenia. Dohan hypothesized that elevated peptide levels from this incomplete metabolism could be responsible for schizophrenic behaviors. In 1979, Jaak Panksepp proposed a connection between autism and opiates, noting that injections of minute quantities of opiates in young laboratory animals induce symptoms similar to those observed among autistic children.

were implicated in a 1982 study by Professor Christopher Gillberg, which suggested a possible link between peptide profiles and autism. However, these findings remain controversial, as a 1988 replication study by Le Couteur et al. did not identify a peptide profile specific to autistic individuals related to casein and gluten degradation.

The possibility of a relationship between autism and the consumption of gluten and casein was first articulated by Kalle Reichelt in 1991. Based on studies showing correlation between autism, schizophrenia, and increased Urine peptide levels, Reichelt hypothesized that some of these peptides may have an opiate effect. This led to the development of the opioid excess theory, expounded by Paul Shattock and others, which speculates that peptides with opioid activity cross into the bloodstream from the lumen of the intestine, and then into the brain. These peptides were speculated to arise from incomplete digestion of certain foods, in particular gluten from wheat and certain other cereals and from casein from milk and dairy produce. Further work confirmed such as (from casein) and and gliadorphin (from gluten) as possible suspects, due to their chemical similarity to opiates.

Reichelt hypothesized that long term exposure to these opiate peptides may have effects on brain maturation and contribute to social awkwardness and isolation. On this basis, Reichelt and others have proposed a gluten-free casein-free (GFCF) diet for those with autism to minimize the buildup of opiate peptides. Reichelt has also published a number of trials and reviews concluding that this diet is effective.

The opioid peptide hypothesis is often cited to support the use of gluten- and casein-free diets in autism. As of 2020, this hypothesis remains unproven. No conclusive evidence has demonstrated an effect of gluten or casein on gastrointestinal symptoms in autistic children. According to Robel et al., the frequency of digestive disorders in autistic children is not significantly higher than in neurotypical children, suggesting that the co-occurrence of these conditions may be coincidental rather than causally linked. Although isolated cases associate autism with celiac disease, no consistent or proven correlation has been established between autism and Coeliac disease or irritable bowel syndrome.

The high prevalence of Eating disorder among autistic individuals has been identified as a potential factor contributing to digestive issues and imbalances in gut microbiota. A study published in Cell in November 2021 by Chloé X. Yap et al. concluded that changes in the intestinal bacterial flora of autistic individuals are likely the result of selective dietary patterns, rather than a cause of autism-related symptoms.

Since the 1970s, studies have examined the effects of casein- and/or gluten-free diets on autistic individuals, partly influenced by an interpretation of a 1979 study by Jaak Panksepp. Research findings have been mixed. A 2002 study involving two groups of autistic children found no significant positive effects from the diet. A 2004 (updated in 2008) reported that current efficacy for these diets was poor but highlighted the need for further investigation. In 2006, a preliminary double-blind clinical trial involving 15 children aged 2 to 16 showed no statistically significant effects, although some parents reported behavioral improvements.

In 2012, a survey of 387 parents who had implemented gluten-free and casein-free diets for their autistic children reported perceived behavioral improvements. However, a 2016 double-blind clinical trial involving 14 autistic children aged 3 to 5 did not demonstrate any significant effect from the dietary intervention.

A first review of the scientific literature was conducted in 2010 by Dr. Austin Mulloy (University of Texas at Austin) and his team. Based on 15 previous studies, the review concluded: "A critical analysis of the methodological rigor and results of each study reveals that the current research body does not support the use of gluten-free and casein-free diets in treating ASD. Given the lack of empirical data and the often negative consequences associated with gluten-free diets ... such diets should only be implemented if an autistic child exhibits acute behavioral changes that appear to be associated with dietary changes, and/or if healthcare professionals confirm through testing that the child has food allergies or intolerances to gluten and/or casein."

In 2013, Dr. Timothy Buie of Boston Children's Hospital conducted a review of studies focusing on gluten and autism and concluded that the available evidence was insufficient to support the use of a gluten-free diet as a treatment for autism. In 2014, Dr. Salvador Marí-Bauset and his team at the University of Valencia published a review in the Journal of Child Neurology, stating that few studies offered strong scientific evidence. They recommended implementing gluten-free and casein-free diets only in cases where food intolerances or allergies had been medically diagnosed. The review also emphasized the need for future studies with more robust designs and larger sample sizes.

In 2015, a review conducted by Klaus W. Lange and colleagues at the University of Regensburg, published in Current Opinion in Clinical Nutrition and Metabolic Care, reached conclusions consistent with previous reviews, finding insufficient evidence to support the use of gluten-free and casein-free diets as a treatment for autism.

In 2020, Busra Baspinar and Hulya Yardimci (University of Ankara) published a review of the scientific literature on gluten-free and casein-free diets in autism. Consistent with previous studies, they concluded that the available research was limited in both quantity and quality, and that the effect of such diets on autistic behaviors remained unclear. They noted that behavioral changes were often assessed through parental self-reports rather than objective evaluation methods.

Other official positions include:

• American Academy of Pediatrics – Clinical Report (2007). In their report, the AAP did not recommend the use of special diets for children with autism spectrum disorder because of inadequate evidence.
• Cochrane Library – Gluten and Casein-free diets in autism spectrum disorder (2008). The Cochrane review found that while relatively commonly used the evidence to support the diets use in children with autism was poor. All studies as of 2006 had issues with them.
• Research in Autism Spectrum Disorders – Gluten-free and casein free diets in the treatment of autism spectrum disorders: A systematic review (2009). It concluded that the results "reveal that the current corpus of research does not support the use of GFCF diets in the treatment of ASD. Given the lack of empirical support, and the adverse consequences often associated with GFCF diets (e.g. stigmatization, diversion of treatment resources, reduced bone cortical thickness), such diets should only be implemented in the event a child with ASD experiences acute behavioral changes, seemingly associated with changes in diet or a child has allergies or food intolerances to gluten or casein."
• Vanderbilt Evidence-based Practice Center – Therapies for Children with Autism Spectrum Disorder (2011). The review, commissioned by the Agency for Healthcare Research and Quality, concluded that, "the evidence supporting GFCF diets in ASD is limited and weak."
• Clinical Therapeutics – The relationship of autism to gluten (2013). This review found one double-blind study, which did not find any benefit from the gluten-free diet, and concluded that "Currently, there is insufficient evidence to support instituting a gluten-free diet as a treatment for autism."
• Journal of Child Neurology – Evidence of the Gluten-Free and Casein-Free Diet in Autism Spectrum Disorders: A Systematic Review (2014). This review found that "...the evidence on this topic is currently limited and weak," and noted that only a few randomized trials had been conducted on the efficacy of gluten-free diets as an autism treatment. The review also noted that even these trials were of questionable scientific merit because they were based on small sample sizes.
• Current Opinion in Clinical Nutrition & Metabolic Care – Gluten-free and casein-free diets in the therapy of autism (2015). This review found "limited and weak" evidence that this diet was effective as a treatment for autism, noting that most studies that had been done to assess its effectiveness were "seriously flawed".
• Autism Research Institute – The Autism Research Institute, an organization with a history of advocating unsupported hypotheses regarding autism, including that it can be caused by vaccines or treated with chelation therapy, recommends the GFCF/GFDF diet as a treatment for autism and related conditions. The organization believes that, "Dietary intervention is a cornerstone of an evidence-based medical approach, and there is convincing empirical evidence that special diets help many with autism."