Having a child diagnosed with autism can be devastating for a parent.
The medical orthodoxy is that autism is a lifelong condition and the diagnosis is usually followed by the advice that there is very little that can be done.
However, a growing number of parents of children on the autism spectrum are using biomedical treatment - a modified diet and added supplements - and have reported impressive results.
Some studies suggest that up to 80 per cent of children have shown some benefit from this approach, with some improving to the extent they are no longer diagnosed as being on the autism spectrum.
The mainstream medical view is that autism is essentially a psychological disorder. By contrast, the biomedical view argues there are biological and physiological causes related to the gastrointestinal problems that many children on the spectrum suffer from, and to their sensitivity to heavy metals and other toxins.
Jan Brenton, the author of Can We Manage Autism - Yes We Can and manager of the Biomedical Autism Group email forum, has championed the use of diet to treat autism.
"A biomedical approach is one where we seek to get to the cause of the problem and treat it by natural means," she says from her Southern Highlands home.
"Any child we see who has a health problem, we investigate them with a few simple medical tests - blood, hair and urine - to see what the heavy metals are like.
"Then we put them onto a very wholesome diet which is gluten, casein and soy free, and very low in sugar, and some very simple supplements like zinc and cod liver oil. We usually see improvements in their health and immunity in a very short while."
The theory is that some people cannot properly digest gluten, casein and soy, which then form peptides - substances that act like opiates.
"Peptides make them go spacey and into their own world," Brenton says.
While many in the medical community remain sceptical, several doctors advocate the biomedical approach and provide specialised advice to families.
While some children show improvements in a matter of days, it is not a quick fix or a miracle cure.
" If you are dealing with a child with autism, it takes about eight years of biomedical care to get to a stage where they are as good in health and cognition and behaviour as a neurotypical child would be," Brenton says.
"Not everybody recovers to that degree, but about 40 per cent of children on the biomedical pathway lose their original diagnosis."
Parents can contact Jan Brenton at email@example.com or via the Biomedical Autism Group at au.groups.yahoo.com/group/biomedicalautismgroup
For more on Brenton's book go to www.manageautism.weebly.com.