Bacteria Could Aid Autistics Clinical Trial Will Put Probiotic Bugs To The Test

By Helen R. Pilcher

Many yoghurts and dairy products claim to contain ‘friendly bacteria’. Might a daily dose of friendly bacteria help treat autism?

UK researchers hope probiotics will soothe the gut problems linked to autism and may even ease psychological symptoms. They are planning a clinical trial to test the idea.

The proposed health benefits of probiotic bacteria are well known. The
beneficial bugs are thought to out-compete other gut bacteria that can cause
diarrhoea and ill health.

So what is the link with autism? Up to 6 people in every 1000 develop
the disorder, which involves difficulties with communication and social
relationships, and many autistics also suffer from bloating, belly-ache and
diarrhoea.

Children with autism are known to have higher levels of one group of
‘bad’ bacteria, Clostridia, in their guts, explains Glenn Gibson from the
University of Reading. So he hopes probiotic food supplements that lower
levels of Clostridia will allay some symptoms of autism.

He is not suggesting that the bad bacteria cause autism: genetic and
environmental factors are both likely to contribute to the complex disorder,
the cause of which is unknown. But toxic by-products of the bacteria may be
absorbed into the blood and travel to the brain, where they may play a role
in ill health.

“The most positive feeling I have is that we will be able to deal with
these gut-related symptoms,” says Gibson. “Any psychological benefits will
be an added bonus.”

Stool Stories
Gibson’s team will study up to 70 autistic children over a one-year
period in a trial starting later this year. Half of the children will take a
daily probiotic food supplement, while the remainder will be given a placebo
drink. Once a month, researchers will analyse stool samples to study gut
flora, and assess psychological and physical symptoms.

At present, the researchers are honing their choice of bacteria. There
are many different types of good bacteria, so it is important to choose one
that can compete effectively against Clostridia.

One candidate, called Lactobacillus plantarum 299v, looks especially
promising. The bacterium binds to the gut lining and stimulates its growth.
As well as out-competing other bacteria, it also lowers gut pH, which helps
the digestive tract to fight infection. It stays in the gut for days and has
never been associated with any health problems.

Multi-Talented Bugs
Friendly bacteria may help to treat other disorders, too. “Probiotics
are beginning to join mainstream medicine in hospitals,” says dietician
Catherine Collins from St George’s Hospital, London.

In Sweden, for example, probiotics are routinely prescribed after
surgery to help boost patients’ immune systems and counter any stomach
upsets that are triggered by antibiotics. This is increasingly the case
elsewhere, says Collins.

The friendly bugs may also prove useful against irritable bowel
disorder, diarrhoea, colitis and bowel cancer, and many studies are under
way to test their health-promoting effects.

With the worldwide probiotic market worth an estimated US$6 billion,
the industry is flourishing. Probiotics come in all shapes and sizes, from
tiny tablets to fruit and yoghurt-based drinks. “Acceptance of their role in
helping to manage illness has been a long time coming but clinical research
is proving their worth,” says Collins.