Gluten-free, casein-free diet

Gluten-free casein-free diet (GFCF diet), also known as gluten-free dairy-free diet (GFDF diet, is a diet that does not include the proteins gluten (found most often in wheat, barley, and rye), and casein (found most often in milk and dairy products).

Despite an absence of scientific evidence, there have been advocates for the use of this diet as a treatment for autism and related conditions.

The majority of the available evidence does not support the use of this diet in the treatment of autism.

The diet may have a negative effect on bone health, although there is debate over whether this is actually due to the diet or caused by eating habits or bowel issues associated with autism.

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 a genetic defect wherein individuals are incapable of completely metabolizing 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.

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 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.

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