These treatments don't work for every child – and many are unproven by the gold standard of clinical trials – but some parents claim they are seeing tangible improvements in their children's autistic behaviour.

They tell of "awakenings" in their children, such as a non-verbal five-year-old suddenly talking and responding to toilet-training.

Anecdotes like this sound "interesting", says Dr Lawrence Bartak, president of Autism Victoria and former president of the Autism Council of Australia.

But he says this type of treatment is "crying out" for more research, to test if the interventions – or some other factor – are contributing to improvements in the child's behaviour.

Autism affects one-in-500 to one-in-1000 Australian children.

Their parents are told there is no known cause or cure. The only proven treatment is behavioural therapy, but it can take years to train an autistic child to overcome symptoms like rigidity to routines, poor understanding of others and speech delay.

Research from the US and Britain has recently been hinting at physical links to autism, such as gut disorders.

British researcher and gastroenterologist Dr Andrew Wakefield has found such a high rate of intestinal dysfunction in autistic children that he calls this a "unique disease process" of autism.

In a colonoscopy study of 110 autistic children he found only three did not show signs of intestinal disorders.

Now Harvard University is working on a medical protocol for treating autism following its research into the gut.

Using 500 gastrointestinal endoscopies with biopsies, Harvard researchers found more than half of autistic children studied had treatable gut disorders including from esophagitis, gastritis and enterocolitis (inflamed gut and bowel).

These findings have excited scientists and parents, because they suggest that if the gut is healed, the autism may also improve.

But this gut-brain link has yet to be conclusively proved and, until a causal link is found, debate will continue to rage over whether gut disorders cause autism or whether they are a side effect.

Although unfamiliar with the Harvard study, Bartak says any reliable and replicated research showing a higher incidence of gut problems in autistic children would be "very interesting".

"It would suggest that there may be some form of congenital abnormality that produces an abnormal gut and is then doing something abnormal to their brain as well," he says.

Sunderland University in Britain has come up with a detailed protocol for treating autism biomedically (ie, treating symptoms in the body).

The Sunderland protocol advocates:

Introducing the child to a dairy-free and gluten-free diet;

Testing for other food allergies and eliminating offending foods;

Testing for vitamin and mineral deficiencies and supplement as needed (commonly zinc, calcium, magnesium, vitamins A, C and some B vitamins);

Testing stools for parasitic organisms such as yeasts or bacteria.

The child is then given treatments to address deficiencies and heal damage to the gut so they can better absorb nutrients.

Protocol co-author Paul Shattock admits some of these interventions are untested and anecdotal.

But at last year's Autism Congress in Melbourne, he recommended that parents start by introducing the dairy-free diet for three weeks to see if their child's behaviour improved.

Sydney pediatrician Dr Antony Underwood has put this form of treatment to the test – with encouraging results.

Underwood claims that a few of his patients now appear to have recovered from autism. They are attending standard schools, making friends and communicating at levels typical for their age.

And while most don't reach full recovery, he has seen improvements in most of the 80 or so autistic children attending his North Shore surgery.

"I see a small group who are fully recovered from autism, a middle group who are improving and a small group who show no response," he says.

Underwood says he cannot tell from the start whether a child will respond to biomedical intervention, but generally younger patients do better, especially if treatment starts between 2½ and 3½ years of age.

He says autistic children often have very high copper levels, multiple food allergies and yeast infestations of the gut that respond well to elimination diets and anti-fungal medications.

If blood or hair tests reveal mineral deficiencies (zinc is usually low), they also show improvement when given mineral supplements.

Add omega 3 and 6 fatty acids and this is enough for some children to lose all signs of autistic behaviour, Underwood says.

Sydney mother Gina Taylor claims her five-year-old son Colin (not his real name) has overcome his autism using these interventions.

Taylor says the ages between two and four were "just appalling" for her family, as Colin's development was severely delayed.

Colin didn't respond to his name, was non-verbal, a fussy eater and felt no pain.

He had also been on several courses of antibiotics and was about to have grommets inserted in his ear to resolve persistent infections.

"Within about two months of his treatment starting, he never needed another course of antibiotics, his pain threshold was normal and he ate a wider diet like eggs, vegies and meat."

While these improvements were welcome, Taylor says the big breakthrough happened a few months later.

"I was in a shoe shop, carrying him as usual so he wouldn't run away, when he leaned over and pointed to a row of shoes and named eight different colours," she says.

After two years of treatment, her son no longer needs speech or occupational therapy, speaks normally for his age and has just started at the local public school.

Brisbane GP Gary Deed also treats autistic patients biomedically.

His Carina clinic sees about 250 autistic children and adolescents. He says most show some improvement if given personalised programs.

"We see a response to symptoms such as digestive symptoms quite quickly in many cases. I have had success with behavioural changes such as stimming (repetitive movements such as flicking and rocking) and agitated self-harming behaviours as well as withdrawal."

Asked if any patient had fully recovered, Deed responded: "I have only truly seen one."

But he says that isn't the goal for most families.

"Most parents accept that they are not looking for 100 per cent recovery, but better ability to self-manage and develop independent living skills.

"To get a child to speak might be as big a milestone for one as it is to finally get toilet-training complete in a seven- to nine-year-old, if you know what I mean."

In fact, doctors who use this approach do not advocate its use without using other treatments such as speech and occupational therapies and learning programs such as applied behavioural analysis (ABA).

While this makes it harder to pinpoint which therapy is responsible for any sudden breakthrough, Underwood says some parents who had tried many therapies without success were turning to chelation.

Underwood says chelation seems to help children whose hair tests indicate high levels of metals such as mercury, lead, aluminium, arsenic, and cadmium.

Chelation is most commonly carried out using agents that bind to the metals in the body. The child then excretes the metals through their urine.

Although chelation has been linked with causing seizures in some children, Underwood says he had seen no cases of this.

But he stresses that it needs to be done under close medical supervision and only once other therapies have been in place for several months.

The fact that some children seem to benefit from chelation suggests they cannot excrete heavy metals or detoxify themselves, he says.

US researcher Dr William Walsh found that 85 per cent of autistic children have a dysfunction in a protein called metallothionein. He believes this may lead to an accumulation of heavy metals in the body, resulting in autistic behaviour.

But deputy director of the National Centre for Immunisation Research, associate professor Peter McIntyre, says chelation therapy has not been thoroughly tested, so its effectiveness has yet to be proven. "I'm aware of people who are practising certain chelation therapies in children with various developmental problems," he says.

"As far as I'm aware, none of them have engaged in any systematic evaluation of this treatment and there's certainly no published data to confirm that it's effective."

But one Sydney mother claims chelation was the turning point for her son, Lachlan, 5.

Linda John says Lachlan's development was normal until 12 months.

By 15 months, she noticed he would no longer look at her and he was constantly fighting ear infections.

And so began the vicious cycle that many parents of autistic children describe.

Repeated courses of antibiotics to clear up the ear infections or wipe out the micro-flora in the bowel, leading to other health problems.

Her son went from having a healthy complexion and stools, to diarrhoea, nightsweats, red cheeks and glazed eyes.

Not even the 18 months he spent at a Sydney school specialising in teaching autistic children could help Lachlan – in fact, his autism worsened.

Lachlan started seeing Underwood, who assessed his gut disorder and started treating him with probiotics, vitamins and minerals.

"I did the gluten-free/dairy-free diet, but I never noticed it made a huge difference."

Lachlan's ear infections cleared up and his complexion improved, but his mind "still wasn't there", she says.

Although she had dismissed chelation before – "it sounded like too much trouble" – she had reached a plateau with his treatment and decided to try it.

"The first few rounds I did, I thought he was getting a little bit more aware, that he'd look at me more, but he still wasn't toileting, he just didn't get it.

"The only way I could describe it was as if I was speaking a different language to him."

Two months into the chelation, Lachlan came home with a note from school to say that for the first time he had completed all the actions to an interactive activity in class.

"Out of the blue they said 'pat your head' and he did it, 'rub your tummy' and he did it, 'touch your toes' and he did it – all with no prompting from anybody.

"It was just unbelievable, that first feeling of 'Oh my God, something has happened here'. From then on he just started using more and more words."

The changes in Lachlan were also noticed by a student speech therapist who teaches Lachlan at home two or three nights a week.

"She couldn't keep up the program quick enough with him," says John. "I've seen her come out of the room with tears in her eyes saying, 'You wouldn't believe how great he went tonight'."

The next big breakthrough was toilet training.

"It took me about two weeks – the connection just happened – he was suddenly aware that that's what mummy wants me to do."

Just when she started to wonder if Lachlan had simply reached an age when he would have improved anyway, she was invited to the school's award night.

Out of 60 pupils, Lachlan won the Encouragement Award for the child who showed the best single improvement over the school year.

"The school could see that his gains were above and beyond what would be expected of a child with his delays, so that was incredible."

John now believes her son was highly reactive to heavy-metal exposure, which is why he didn't show much improvement until the chelation therapy.

"The biggest breakthrough has been watching the chelation because I felt like perhaps all the other stuff I did was groundwork and the chelation was the icing on the cake.

"I'll never know what Lachlan would have been like had I not done everything, but I don't believe I would have the good little boy I've got now."

Autism Victoria
Royal Institute for Deaf and Blind Children