Gluten-free, casein-free diet
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A gluten-free casein-free diet (or GFCF diet) eliminates intake of the naturally-occurring proteins gluten (found naturally in wheat, barley, and rye) and casein (found in milk). The Autism Research Institute and other advocacy groups recommend the diet as a treatment for autism and related disorders. Studies supporting these claims have had significant flaws, and the data are inadequate to guide treatment recommendations.[1][2]
Background and theory
In the 1960s, 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.[3] Dohan proposed genetic defect as a probable etiology for schizophrenia, wherein individuals were incapable of completely metabolizing gluten and casein. The consequence of incomplete metabolism is excess peptide levels in the gastrointestinal tract, which Dohan hypothesizes are responsible for schizophrenic behaviors.
The possible relationship between gluten, casein, and autism was first articulated by Kalle Reichelt, M.D. in 1991.[4] Based on studies showing correlation between autism and increased urinary peptide levels, Reichelt hypothesized that some of these peptides may have an opiate effect. Further work determined opioid peptides such as casomorphines[5] (from casein) and gluten exorphines and gliadorphin (from gluten) as possible suspects, due to their chemical similarity to opiates. Reichelt hypothesizes 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 to minimize the buildup of opiate peptides and promote typical development of brain function.
Reichelt's hypothesis is not generally regarded as a definitive etiology for autism, nor is the GFCF diet advocated as a "cure".[6]
Effectiveness
A gluten-free diet is a well-established treatment for celiac disease[7] and for dermatitis herpetiformis.[8]
Reports on the effectiveness of the GFCF diet for autism come overwhelmingly from testimonials of individual parents or teachers. Reported results range from no discernible effect to claims of complete recovery following implementation of a gluten-free casein-free regimen.[9] There have been insufficient adequately designed, large-scale controlled studies and clinical trials to state whether the GFCF diet is effective.[2] A small single blind study has documented fewer autistic behaviors in children fed a gluten-free, casein-free diet, but noted no change in cognitive skills, linguistic ability or motor ability.[10] This study has been criticized for its small sample size, single-blind design which may have skewed the results as effectiveness was determined in part by interviewing the parents, who knew whether their child was receiving the GFCF diet.[1]
A 2006 double-blind short-term study found no significant differences in behavior between autistic children on a gluten-free, casein-free diet and those on regular diets.[9]
Safety
A 2008 study found that autistic boys had significantly thinner bones than neurotypical boys, starting around age 5–6 years, and that boys with 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 autistic boys, 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.[11]
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 or cheese, but is also present in smaller amounts in many substitute dairy products such as vegetarian cheese substitutes, which use casein to provide texture. On a separate note, whey is a different milk protein from casein and can be included in this diet.
See also
References
- ^ a b Christison GW, Ivany K (2006). "Elimination diets in autism spectrum disorders: any wheat amidst the chaff?". J Dev Behav Pediatr. 27 (2 Suppl 2): S162–71. doi:10.1097/00004703-200604002-00015. PMID 16685183.
- ^ a b Millward C, Ferriter M, Calver S, Connell-Jones G (2008). "Gluten- and casein-free diets for autistic spectrum disorder". Cochrane Database Syst Rev (2): CD003498. doi:10.1002/14651858.CD003498.pub3. PMID 18425890.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Dohan, F.C. (1966) Cereals and Schizophrenia, data and hypothesis Acta Physiologica Scandinavica, 42, 125-132.
- ^ Reichelt KL, Knivsberg A-M, Lind G, Nødland M. Probable etiology and possible treatment of childhood autism. Brain Dysfunct 1991; 4: 308-19
- ^ Sun, Z. and Cade, J.R. (1999) A peptide found in schizophrenia and autism causes behavioral changes in rats. Autism, 3(1), 85-95.
- ^ White, John F. (2003) "Intestinal Pathology in Autism" Experimental Biology and Medicine, 228, pp. 639-649.
- ^ "NIH Consensus Development Conference on Celiac Disease". NIH Consens State Sci Statements. 21 (1): 1–23. 2004. PMID 17308551.
- ^ Turchin I, Barankin B (2005). "Dermatitis herpetiformis and gluten-free diet". Dermatol Online J. 11 (1): 6. PMID 15748547.
- ^ a b Elder JH, Shankar M, Shuster J, Theriaque D, Burns S, Sherrill L (2006). "The gluten-free, casein-free diet in autism: results of a preliminary double blind clinical trial". J Autism Dev Disord. 36 (3): 413–20. doi:10.1007/s10803-006-0079-0. PMID 16555138.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Knivsberg, A.M. (2002). "A randomised, controlled study of dietary intervention in autistic syndromes". Nutritional Neuroscience. 5 (4): 251–261. doi:10.1080/10284150290028945. PMID 12168688.
{{cite journal}}:|access-date=requires|url=(help); Unknown parameter|coauthors=ignored (|author=suggested) (help) - ^ Hediger ML, England LJ, Molloy CA, Yu KF, Manning-Courtney P, Mills JL (2008). "Reduced bone cortical thickness in boys with autism or autism spectrum disorder". J Autism Dev Disord. 38 (5): 848–56. doi:10.1007/s10803-007-0453-6. PMID 17879151.
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