Gluten- and casein-free diets for autistic spectrum disorder.
BACKGROUND
It has been suggested that peptides from gluten and casein may have a role in the origins of autism and that the physiology and psychology of autism might be explained by excessive opioid activity linked to these peptides. Research has reported abnormal levels of peptides in the urine and cerebrospinal fluid of persons with autism. If this is the case, diets free of gluten and /or casein should reduce the symptoms associated with autism.


OBJECTIVE
To determine the efficacy of gluten- and/or casein- free diets as an intervention to improve behaviour, cognitive and social functioning in individuals with autism.


METHODS
Electronic searching of abstracts from the Cochrane Library (Issue 3, 2003), PsycINFO (1971- May 2003), EMBASE (1974- May 2003), CINAHL (1982- May 2003), MEDLINE (1986- May 2003), ERIC (1965-2003), LILACS (to 2003) and the specialist register of the Cochrane Complementary Medicine Field (January 2004). Review bibliographies were also examined to identify potential trials.


METHODS
All randomised controlled trials involving programmes which eliminated gluten, casein or both gluten and casein from the diets of individuals diagnosed with autistic spectrum disorder.


METHODS
Abstracts of studies identified in searches of electronic databases were read and assessed to determine whether they might meet the inclusion criteria. The authors independently selected the relevant studies from the reports identified in this way. As only one trial fitted the inclusion criteria, no meta-analysis is currently possible and data are presented in narrative form.


RESULTS
The one trial included reported results on four outcomes. Unsurprisingly in such a small-scale study, the results for three of these outcomes (cognitive skills, linguistic ability and motor ability) had wide confidence intervals that spanned the line of nil effect. However, the fourth outcome, reduction in autistic traits, reported a significant beneficial treatment effect for the combined gluten- and casein- free diet.


CONCLUSIONS
This is an important area of investigation and large scale, good quality randomised controlled trials are needed.
Millward
C
C
Ferriter
M
M
Calver
S
S
Connell-Jones
G
G
D001321:Autistic Disorder / Q000178:diet therapy* / Q000209:etiology / Q000523:psychology; D002364:Caseins / Q000008:administration & dosage / Q000009:adverse effects; D002648:Child; D003071:Cognition; D003142:Communication; D005983:Glutens / Q000008:administration & dosage / Q000009:adverse effects; D006801:Humans; D001523:Mental Disorders / Q000178:diet therapy; D009043:Motor Activity; D010455:Peptides / Q000652:urine; D016032:Randomized Controlled Trials as Topic
D002364:Caseins; D010455:Peptides; D005983:Glutens