"It's better to light a candle than curse the darkness"

The GFCF Diet Loses its Legs

March 22nd, 2008

Spring is here, according to the calendar, although the fresh snow on the ground would seem to contradict that idea. At any rate, the Winter quarter is over, the tests have been graded and the final grades submitted to the Registrar and I finally have time to attend to my much-neglected ‘blog.

A lot has happened in the autism world since my last post. The VICP has agreed to pay damages to the family of a young girl whose mitochondrial dysfunction was possibly worsened by her reaction to vaccines. I say “possibly” because it is not at all clear what mitochondrial dysfunction she has, and so it is impossible to assess the biological plausibility of the claim.

This same restraint has not been shown by many in the vaccines-cause-autism camp, who are trumpeting this “victory” to the skies. They are apparently unaware that even if her autism were caused by the interaction of a mitochondrial dysfunction and vaccines, it is unlikely that a significant portion of autism is caused in this way. Again, not that I haven’t conceded that the vaccines were the “trigger” for this young girl’s autism – that has yet to be shown.

It has been fascinating (“appalling” might be a better word) to watch the many “autism advocates” rush to get on the new vaccines-and-mitochondrial-dysfunction-cause-autism bandwagon. I am reminded of a whale-watching trip I took, where most of the passengers kept rushing from starboard rail to port rail, following the cries of “There’s one!” ignoring the naturalist who was trying (largely in vain) to point out the real whales (instead of whitecaps and kelp).

In the midst of all the hoopla about mitochondria, two pieces of real research were published that should have a major impact on the way the followers of DAN! are treating their children.

Cass H, Gringras P, March J, McKendrick I, O’Hare AE, Owen L, Pollin C., Absence of urinary opioid peptides in children with Autism. Arch Dis Child. 2008 Mar 12 [Epub ahead of print]

In this study, Cass et al examined the urine of 65 boys with autism and 158 boys without autism (controls). They used HPLC (high-pressure liquid chromatography) to identify potential opioid peptides in the urine and then further examined these with MALDI-TOF MS (matrix-assisted laser desorbtion ionisation-time of flight mass spectroscopy).

Their results?

“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.”

This study confirms the finding of Hunter et al (Opioid peptides and dipeptidyl peptidase in autism. Dev Med Child Neurol. 2003 Feb;45(2):121-8.), whose study found that:

“Opioid peptides were not detected in either the urine of children with autism (10 children; nine males, one female; age range 2 years 6 months to 10 years 1 month) or their siblings (10 children; seven males, three females; age range 2 years 3 months to 12 years 7 months) using liquid chromatography-ultraviolet-mass spectrometric analysis (LC-UV-MS).”

Of course, the Cass et al study has more subjects and uses much more sophisticated, sensitive and accurate instrumentation, but it had the same findings. One wonders what it was that Dr. Reichelt was finding in the urine of autistic children. Whatever it was, it apparently wasn’t an opioid peptide.

For those who are new to controversies in autism, the “opioid peptide hypothesis” was the driving force behind the gluten- and casein-free (GFCF) diet.

It was postulated, by Karl Reichelt and others, that the proteins gluten (found in many grains, esp. wheat) and casein (found in milk, including human milk) were being broken down to shorter oligopeptides (proteins consisting of only a few amino acids) that were mimicking the endogenous opioid peptide (endorphins and enkephalins) in the brain.

It was further postulated that these “opioid peptides” were being absorbed through the “leaky gut” of autistic children (more on this later) and causing many or all of the symptoms of autism.

Now that it has been shown – twice – that there are no opioid peptides in the urine of autistic (or non-autistic) children (as there would be if they had been absorbed into the bloodstream), the primary hypothesis supporting the GFCF diet has been disproven. All that’s left is the rather pathetic argument “But it works!” – pathetic because the studies done to date (Knivsberg et al 2002, Sponheim 1991 and Elder et al 2006) have been mixed. Actually, only the study that included Karl Reichelt as an investigator (Knivsberg et al 2002) showed any improvement on the diet – the others showed no difference between the diet and control groups.

The other significant recent study looked at the other “leg” supporting the GFCF diet – the “leaky gut” hypothesis.

Robertson MA, Sigalet DL, Holst JJ, Meddings JB, Wood J, Sharkey KA. Intestinal Permeability and Glucagon-like peptide-2 in Children with Autism: A Controlled Pilot Study. J Autism Dev Disord. 2008 Feb 29 [Epub ahead of print]

This study looked at the intestinal permeability and glucagon-like peptide-2 (GLP-2) response to feeding, both of which have been claimed to be abnormal in autistic children. They used the lactulose:mannitol sugar permeability test for intestinal permeability.

This was a pilot study, with 14 autistic children and 15 controls (7 developmentally normal siblings of the autistic subjects and 8 unrelated developmentally normal children).

The results?

“Our study did not detect differences in these measures of gastrointestinal function in a group of children with autism.”

Of course, this is just a pilot study and will – I hope – lead to a larger study with great predictive power. Another recent study of 23 children with PDD (Kemperman et al 2008) also showed no abnormal intestinal permeability. This calls into question the one study (D’Euphemia et al 1996) that found altered intestinal permeability in 9 out of 20 autistic subjects (and 0 of 40 controls).

Now, I’m not naïve enough to think that either of these studies will have the slightest impact on the people who have their children on the GFCF diet. It wasn’t the data that convinced them to start the diet, so data won’t convince them to stop the diet. No, what I hope is that parents who are contemplating the GFCF diet will read these studies and think about it.

I also anticipate a number of impassioned stories about how the GFCF diet “recovered” their autistic child. I have no doubt that the people who write them are going to be very sincere, telling the “truth” as they see it. I also expect that I won’t be hearing from the parents who tried the GFCF diet and saw no results.

That’s the nature of things – the people who try it (whatever “it” might be) and experience improvement will attribute that improvement to whatever they tried. They will have become true believers and will be eager to share their discovery. The parents who try the GFCF diet and saw no improvement will not be nearly as eager to talk about their experiences. Especially given the hostility their story will generate among the “true believers”.

So, for those of you who still have open minds, the data has been laid before you. Enjoy!

For the rest of you – just pretend that I’m in the pay of “Big Pharma” or whatever fever-dream conspiracy is trying to suppress the “truth” about the GFCF diet. It will help with the cognitive dissonance.

Prometheus

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