Archive for 5. February 2011

Elimination diets in autism spectrum disorders: any wheat amidst the chaff?

Christison GW, Ivany K.

Department of Psychiatry, Loma Linda University School of Medicine, Loma Linda, California 92354, USA. gchristison@llu.edu

Abstract

The use of complementary or alternative treatment approaches in children with autism spectrum disorders (ASDs) is increasing, and the most popular of such approaches are diets that eliminate either gluten or casein, or both. The popularity of these diets indicates a need for more rigorous research into their efficacy. Owing to significant methodological flaws, the currently available data are inadequate to guide treatment recommendations. The purpose of this review is to examine the available trials of gluten/casein diets in children with ASDs regarding the strength of their findings and also concerning points that may be useful in the design of future studies. Seven trials of these diets in ASD are critically reviewed; 6 of these were uncontrolled trials and 1 used a single-blind design. All reported efficacy in reducing some autism symptoms, and 2 groups of investigators also reported improvement in nonverbal cognition. Design flaws in all of the studies weaken the confidence that can be placed in their findings. Careful double-blind, placebo-controlled studies are needed to evaluate whether actual benefit undergirds the diets’ popularity and to provide better guidance to clinicians and caregivers. The literature currently available suggests that diets eliminating both gluten and casein (rather than either alone) should be studied first and that outcome measures should include assessments of nonverbal cognition.

Can the pathophysiology of autism be explained by the nature of the discovered urine peptides?

Reichelt KL, Knivsberg AM.

Institute of Pediatric Research, Univ of Oslo, Rikshospitalet, N-0027, Oslo, Norway. k.l.reichelt@klinmed.uio.no

Abstract

Opioid peptides derived from food proteins (exorphins) have been found in urine of autistic patients. Based on the work of several groups, we try to show that exorphins and serotonin uptake stimulating factors may explain many of the signs and symptoms seen in autistic disorders. The individual symptoms ought to be explainable by the properties and behavioural effects of the found peptides. The data presented form the basis of an autism model, where we suggest that exorphins and serotonin uptake modulators are key mediators for the development of autism. This may be due to a genetically based peptidase deficiency in at least two or more peptidases and, or of peptidase regulating proteins made manifest by a dietary overload of exorphin precursors such as by increased gut uptake.

Diets for autistic spectrum disorder

Gluten and casein free diets for autistic spectrum disorder

Millward C, Ferriter M, Calver S, Connell-Jones G.

Update in:

Abstract

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.

OBJECTIVES: 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.

SEARCH STRATEGY: 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.

SELECTION CRITERIA: 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.

DATA COLLECTION AND ANALYSIS: 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.

MAIN 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.

REVIEWERS’ CONCLUSIONS: This is an important area of investigation and large scale, good quality randomised controlled trials are needed.

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