They found no significant group differences.

A review of abstracts in databases by Millward C, Ferriter M, Calver S, Connell-Jones G. looked at only a limited number of outcomes:

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.

The authors suggested that “large scale, good quality randomised controlled trials” are needed.

A 2006 Norwegian study looked at urine peptide patterns in children with “milder types of autism” which (in the study) refers to children without mental retardation or milder mental retardation:

No significant differences in urine peptide values were found between the autism spectrum disorders group and the controls. There was an age dependent decrease in peptides, with values decreasing with the age of the child. Three individuals in the autism group (17%) and one in the familiar control group (0.05%) had high levels of urine peptides. No one in the same age non-familiar control group had elevated levels of urine peptides

The study concluded that “high-functioning autism cannot be identified by the urine peptide pattern,” while noting autism “is probably not homogenous”—-and suggesting that individuals with “milder forms of autism” might represent a more homogenous group.

@vsheehan, yes; thank you for asking.

I’ll speculate that one reason for the specific notation of the GF and CF diets is because of the recent attention given to a special diet in the media and also the association of this theory with Andrew Wakefield.

@pD,

It’s the case that when we first, many years ago, looked at books (academic and popular) about autism, my husband and I noted that diarrhea and GI problems were mentioned by many families. In our experience, my son’s communication difficulties have made it difficult for him to let us know when he might have a stomach or need to get to a restroom in time, and therefore highlighted these sorts of problems. As noted, over time, the need to be completely GF and CF has lessened considerably, with no effects on behavior or learning.

What I found interesting was the fact that apparently some differences were found, but that it was determined that whatever was found, it wasn’t opioid peptides. No mention was made in the abstract if they were differences between groups.

http://adc.bmj.com/cgi/content/abstract/adc.2006.114389v1

From the abstract:

“Outcomes: There were no significant differences between the HPLC urinary profiles of the children affected by autism and the typically developing controls. In those cases where HPLC showed peaks in the locations at which opioid peptides might be expected to be found., MALDI-TOF established that these peaks did not, in fact, represent opioid peptides at all. ”

Perhaps this is an explanation of why peptides were originally found by one set of researchers, never to re-appear again. It might be nice to know what the peaks did actually represent. (Free copies of the entire paper don’t appear to be available)

I’d like to second the above opinion that an absence of peptides does not necessarily invalidate the leaky gut theory; the theory does not require MMR, nor does it require peptides; it only requires differential intestinal permiability.

There have been other studies showing differential uptakes of sugars by autistics and controls, suggesting permiability issues.

http://www.ncbi.nlm.nih.gov/pubmed/8888921?ordinalpos=2&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_RVDocSum

There are also several studies showing differential reaction to dietary proteins of several varieties exhibited by the blood cells of autistics when compared with controls.

Take care all!

- pD

thanks for noting the Newsweek piece!