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[PinkSmartie]

Controversial autism diet

Despite an absence of scientific evidence, the Autism Research Institute recommends the GFCF diet as a treatment for autism and related conditions. A study by the University of Rochester found "eliminating gluten and casein from the diets of children with autism had no impact on their behavior, sleep or bowel patterns".
The study mentioned was performed with a small group - 14 children - and they selected only ones without any gastrointestinal (GI) issues. Another study showed that nearly half of children with autism have GI issues. The University of Rochester researchers acknowledged that children with significant gastrointestinal (GI) symptoms might receive some benefit from dietary changes.

Background and theory

In the 1960s, Curtis Dohan speculated that the low incidence of schizophrenia in certain South Pacific Island societies was a result of a diet low in wheat and milk-based foods. Dohan proposed agenetic defect wherein individuals are incapable of completely metabolizing gluten and casein as a possible etiology 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.
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 urinary 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 opioid peptides such as casomorphines (from casein) and gluten exorphines 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 sufferers of autism to minimize the buildup of opiate peptides. Scientific evidence from randomized controlled trials confirming or disconfirming the effectiveness of the GFCF diet is lacking.

Effectiveness

The most recent systematic review, conducted in 2009, concluded that the evidence in support of the theory is "limited and weak", noted known adverse consequences associated with the diet, and advised against its therapeutic use. The review identified 14 studies testing the effects of GFCF diet on autism. Of these, 7 reported positive results, 2 reported mixed results, and 4 reported negative results (that is, absence of statistically significant effects). Among studies reporting negative results, none were longer than 6 weeks, with two out of four studying effects of the diet for 4 days and 9 days. Only two double-blind studies were identified, and both of these produced negative results.
A 2008 systematic review from the Cochrane Library indicates that a gluten-free and/or casein-free diet has not been shown to have any effect on the behavior or functioning of individuals with autism. Likewise, research on adverse outcomes and disbenefits is lacking. Two randomized trials were included in the review. The first included ten individuals, was single blind (with parents aware of allocation), and reported reduced autistic traits; the second included fifteen individuals, was double blind, and found no significant differences in outcomes. The first study has been criticized for its small sample size and single-blinding; both factors are associated with positive outcomes bias.
Testimonials of individual parents and teachers range from no discernible effect to claims of complete recovery.

Safety

A 2008 study found that boys with autism had significantly thinner bones than non-autistic boys, starting around age 5–6 years, and that boys using casein-free diets had nearly twice the bone thickness deficiency as boys with minimally restricted or unrestricted diets. It is not known which other factors contribute to thin bones in boys with autism, but it appears that a casein-free diet may contribute to calcium and vitamin D deficiencies that lead to decreased bone development and increased risk of broken bones.

Practical implementation


The implementation of a GFCF diet involves removing all sources of gluten and casein from a person's diet. Gluten is found in all products containing wheat,rye, and barley. Many gluten-free breads, pastas, and snacks are available commercially. Gluten-free cookbooks have been available for decades. Casein is found in dairy products such as milk, butter or cheese, but is also present in smaller amounts in many substitute dairy products such as vegetarian cheese substitutes and whipped cream topping, which use casein to provide texture. Although advocates of the GFCF diet often recommend total elimination of dairy from the diet, whey protein is a different milk protein from casein.
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