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 gluten proteins (found most often in wheat, barley, and rye), and casein (found most often in milk and dairy products). In spite of the absence of scientific evidence, there have been advocates for the treatment of autism and related conditions.
The majority of the evidence does not support the use of this diet in the treatment of autism.
The diet may be a negative effect on bone health, or is caused by autism.
In the 1960s, Curtis Dohan speculated that the low incidence of schizophrenia in some South Pacific Island societies was a result of a low-fat diet and milk-based foods. They are unable to completely metabolize gluten and casein as a possible cause for schizophrenia. Dohan hypothesized that elevated peptide levels of 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 animals. 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. Opioid Excessive Theory, expounded by Paul Shattock and others, which speculates that opioid-based peptides in the brain, and then into the brain. These peptides have been speculated to arise from incomplete digestion of certain foods, in particular from certain wheat cereals and from casein from milk and dairy produce. Further work confirmed opioid peptides such as casomorphins (from casein) and gluten exorphins 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. Reichelt has also published a number of trials and reviews concluding that this diet is effective.
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 commercially available. Gluten-free cookbooks have been available for decades. Casein is found in dairy products, such as butter or cheese, but is also present in the form of a substitute for dairy products such as vegetarian cheese substitutes and whipped cream topping, which use casein to provide texture. Although advocates of the GFCF diet often recommends total elimination of dairy from the diet, whey protein is a different milk protein from casein.