Probiotics and Autism

John Scott reports and Professor Glen Gibson comments of the research.

It is well known that autistic children often suffer from gastrointestinal discomfort, bloating and diarrhoea or constipation, and it has been discovered recently that the intestines of autistic children tend to contain a higher number of the Clostridium histolyticum group of bacteria than is found in healthy children.

Clostridia are well-known producers of toxins, including neurotoxins, which may contribute to gut disfunction, may also have a systemic effect and could potentially be a contributory factor in the development of autism.

Researchers at the Food Microbiology Sciences Unit at Reading University have developed a probiotic specifically to reduce the levels of clostridia and promote 'friendly' bacteria instead, and they recently mounted a trial to assess precisely what effects this would have on autistic children.

Forty children, aged 4 to 8 were selected and half were given Lactobacillus plantanum in a powder, once a day, whilst the rest received a sham 'probiotic'.

As this was a 'blind' study, none of the participants knew which product they were getting, but it appears that the reduction of autistic symptoms in the children who were taking the L. plantanum was so remarkable to their parents that, when the time came in the study for the groups to switch and for those who had been taking the real probiotic to begin taking the sham product, the parents refused to accept anything other than the genuine probiotic!

Inevitably, the trial collapsed due to the large number of drop-outs and no firm conclusions could be drawn in a 'scientific' sense, although a very clear 'result' may be obvious to many!

A new trial is to be mounted that should answer some of the remaining questions, such as whether the obvious improvement in both concentration and behaviour was due simply to the fact that the children felt better, and were therefore more able to concentrate and behave more normally, or whether this was due to some other change brought about by the probiotic.

Source: The Scotsman, 5 September 2006. Click here for the online article and comments.

A further enquiry from Professor Gibson as to the exact probiotic used in the trial elicited this response:

I attach some further information on our research into ASD's.

A recently completely human intervention (all done blind coded and double armed crossover - 3 weeks each period with washouts in between) seemed to exert a positive effect in many instances - it involved a non commercial strain of Lactobacillus plantarum.
We were aiming to reduce GI symptoms likely caused by high clostridia (pathogens) in the children. The outcome involved a slight increase in lactobacilli in stools during the test period but also positive data from the psychological assessments, gut symptoms and parents comments. We fed the probiotic as a powdered supplement rather than dairy drink.

The microbiology was done by new culture independent techniques that rely upon differences in the DNA patterns of the bacteria. Ages were 4-13years.

The bad news is that we suffered from a 50% drop out. This was disappointing and means we lost our power calculation (which dictates the number of trialists you need to complete for a statistically valid conclusion). Because of this we can only view the trial as a failure unfortunately.

So, the trial gives us optimism - albeit cautious. However, it can't be published in a top journal as we had hoped.

The work is all being collated into a PhD thesis right now. It will summarise 4 years research (lab and human). Some is published and the rest will be following the thesis completion.

Another parent has informed me that they ordered capsules of lp299V(Lactobacillus plantarum) from Quest. I have to mention however that this is the same species as our test one - but not the same strain. It is a relative but not actually the one tested.

I would very much like to do a larger study and hope for less drop outs but the problem I have is that this one was very expensive and I did not look for commercial sponsorship. It was funded by my own personal research account and my University - and if we can't publish as we hoped then it is a bit discouraging. I only hope that sometime independent sponsors like research councils show some interest. Much more research is needed, even if it is disproving an avenue.

Here are some parent comments (although I stress they are subjective):
Treatment period:
* More calm, relaxed, not stressed, no mood change, content
* Improved ability to listen & concentrate
* Better formed stools

Washout Period:
* Heartbreaking to see the improvements deteriorating
* Loose stools & undigested food particles
* Abdominal pain
* Depressed mood


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First Published in 2007

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