By Clive Cookson, Science Editor
The theory that some symptoms of autism are caused by problems in the gut will be put to the test later this year, when scientists begin clinical trials of probiotics – “friendly bacteria” – in autistic children.
Glenn Gibson, professor of food microbiology at Reading University, said yesterday that studies of 210 children with autism in the US and UK showed exceptionally high levels of harmful bacteria, known as clostridia, in their guts. Those with brothers or sisters had much more clostridia than their siblings.
“We are now screening several strains of probiotic bacteria to see
which will intervene against these clostridia,” said Prof Gibson. “Human
trials will start later this year using the probiotic which performs best.”
Although the link between autism and gut disorders is scientifically
controversial, he has no doubt that autistic children do have bowel
abnormalities. The nature of the association is uncertain.
Prof Gibson’s theory is that the “gut flora” fail to develop normally
during early childhood, allowing clostridia to take hold. These bacteria
produce toxins that may damage the brain, contributing to the
characteristics of autism. “But it is just a hypothesis at this stage,” he
emphasised.
The trial – to be carried out jointly with Frimley Children’s Centre
in Hampshire – will involve 50 to 70 children with autism aged five to
eight, who will be divided into two groups. One will receive daily drinks
containing probiotic bacteria and the other will receive placebos. The
groups will be monitored to see whether the probiotic bacteria suppress
harmful clostridia and if this produces any psychological changes.
Prof Gibson was speaking at the launch of Proviva Shot!, a probiotic
drink, although his research will be conducted independently.