Experts say there is no strong proof that removing gluten and casein from an autistic child’s diet will improve his behaviour. APRIL CHONG reports

Critics of a controversial gluten-free, casein-free diet, which claims to treat autism in children, have received some backing from a recent study.

Advocates of the gluten-free, casein-free (GFCF) diet say it is able to calm an autistic child.

The symptoms of autism, a neurological disorder, include poor social skills and repetitive behaviour.

Gluten is found in wheat, barley and rye and casein in dairy products.

The GFCF diet for autistic children is based on the hypothesis that such children have problems digesting gluten and casein properly, said Ms Christine Ong, the chief dietitian at KK Women’s and Children’s Hospital.

However, in January this year, a study by a panel of 28 experts from the United States found that current evidence does not support this special diet’s claim. At most, it has benefited some autistic children.

Their findings were published in the journal Pediatrics.

The panel reported that digestive problems do affect both autistic and non-autistic children.

Ms Ong added that GFCF advocates also suggest that the intestines of autistic children are more porous than normal.

As a result, they say, incompletely digested gluten and casein “leak” through the intestinal linings and cause behavioural, communicative, social and cognitive difficulties.

This is the so-called “leaky gut” hypothesis, with some speculating that this causes autism itself.

How did this theory emerge?

The protein by-products of casein and gluten can exert a morphine-like effect in the brain, said Dr Ang Poon Liat, a consultant paediatrician from Thomson Paediatric Centre.

This morphine-like effect blocks or reduces the sensory inputs of touch, pain, hearing, taste and sight.

In the case of a child, this may lead to his developing poor sensory integration, high pain tolerance and delayed speech, said Dr Ang, who has come across parents saying that the diet seemed to work on their autistic children.

In 2002, a Norwegian team had said in the journal Nutritional Neuroscience that autistic children on the GFCF diet fared better in many areas: they were less anxious, behaved better and learnt faster.

Some studies also reported that the removal of casein and gluten from the diet reduced certain proteins in the urine. These studies related this to certain improvements such as better behaviour in the autistic child, as observed by parents.

However, these are digestive issues and there is no strong proof of a link between these compounds and an autistic child's behaviour, said Dr Tammi Quek, an associate consultant at the University Children's Medical Institute at the National University Hospital.

Many other studies have also found no significant differences.

Indeed, last month, the prestigious medical journal Lancet retracted a 1998 study which first suggested the link between autism and gastrointestinal problems.

While the diet may benefit some autistic children, the US panel said more studies are needed to determine markers that identify the children who may be helped by the diet.

Medical professionals also reported a range of anecdotal observations from parents who have put their children on the GFCF diet – from those who saw no effect to those who reported success.

Ms Ong said the GFCF diet should not be recommended in the routine management of children with autism because of conflicting evidence on its effectiveness.

She added that it is possible that some children with autism are just reacting to gluten and casein because of an allergy or immune system problem.

Parents who want to give the GFCF diet a try should seek the advice of doctors and dietitians, she said.

Dr Quek said: “If parents restrict the diet of a child too tightly by cutting down on protein, fats, vitamins and minerals, there is the danger of malnutrition in the child.

“Currently, we only advise a gluten-free diet if the child is proven to suffer from coeliac disease, a gastrointestinal problem that is not related to autism.”

Dr Ang added that not all children will benefit from a GFCF diet and recommended a three-month trial to see if it was worth the trouble of having to find other nutrition sources.

“Parents must apply their common sense and intuition about what is best for their own child. The final arbiter is the child's response to the treatment,” he said.