(PhysOrg.com) -- The use of gluten-free and/or casein-free (GFCF) diets in the treatment of autism spectrum disorders (ASD) is not supported by current research, says a team of scientists with The University of Texas at Austin's Meadows Center Autism Spectrum Disorders Institute.
The conclusion was reached after critical analysis of 15 published, major scientific studies on GFCF as an effective treatment method for ASD.
"Many causes for ASD have been proposed," says Austin Mulloy, lead researcher on the study and doctoral student in the Department of Special Education at The University of Texas at Austin, "and even though the actual etiology remains unknown, potential causes have been translated into treatment methods and shared with the public well before there is sufficient evidence regarding treatment effectiveness or safety."
"Among the many proposed causes is the theory that people with autism have insufficient enzymatic activity in the gastrointestinal tract and increased gastrointestinal permeability. It's suggested that they tend to absorb toxic byproducts of the incompletely digested proteins casein and gluten.
"Casein is a naturally occurring protein found in milk and other dairy products and gluten is a protein in wheat, barley and other grains. Consequently, the number of parents who have elected to put their children with autism on gluten- and casein-free diets has increased significantly in the past several years."
The research team reported that a number of gross methodological flaws invalidate studies that show support for using the diet as an ASD treatment. According to Mulloy and his colleagues, a number of documented phenomena other than efficacy of the GFCF diet can explain the outcomes observed in the studies.
"Given that a variety of adverse consequences are known to be associated with a gluten- and casein-free diet," says Mulloy, "my fellow researchers and I recommend that the diet only be implemented with children whose doctors have identified them as having allergies or intolerances to gluten or casein."
Autism spectrum disorder refers to neurological and developmental disorders that include autism, Asperger syndrome and a range of other pervasive developmental disorders. Defining features of ASD include impairments in social interaction, communication and imagination along with restricted interests and, in some cases, intellectual disability. Current estimates suggest that about one in every 100 children is diagnosed with ASD.
Other researchers who contributed to the study include Russell Lang, University of California, Santa Barbara; Mark O'Reilly, The University of Texas at Austin; Jeff Sigafoos, Victoria University of Wellington, New Zealand; Guilio Lancioni, University of Bari, Italy; and Mandy Rispoli, Texas A&M University.
The study was published in the summer 2010 edition of the peer-reviewed journal Research in Autism Spectrum Disorders.