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The Science and Fiction of Autism

What can cause it, and what doesn't


A pervasive neurodevelopmental disorder, autism is characterized by impaired social interaction and communication; withdrawal and isolationism; and repetitive, obsessive, and/or infantile behaviours.

There is much yet to learn about the causes and treatments associated with autism. A pervasive neurodevelopmental disorder, autism is characterized by impaired social interaction and communication; withdrawal and isolationism; and repetitive, obsessive, and/or infantile behaviours.

More properly termed autism spectrum disorder (ASD) or pervasive developmental disorder, the autistic spectrum encompasses “quiet loners” who are near normal in intellectual ability to virtually incommunicative persons who are unable to function in any situation.



ASD diagnoses have increased in all western countries in the past 15 years; currently about one in 170 North American children has this disorder. Most of the increased incidence of ASD is due to increased awareness—but awareness cannot account for all the new cases.

Modern medicine has reduced the incidence of many pediatric disorders, but is currently unable to prevent or reverse ASD.



It’s clear that ASD has underlying genetic causes; however, multiple genes and complex genetic defects are involved. Epidemiological observations reveal how the condition is genetically based:

  • 80 percent of cases are male.
  • The risk of ASD in siblings is between 2 and 8 percent greater than in unrelated children.
  • Identical twins have an up to 92 percent rate of both having ASD.
  • Fraternal twins have an up to 10 percent rate of both having ASD.
  • Extended families with multiple ASD children have a subset of relatives with social and language deficits (obsessive-compulsive disorder, social phobia, delayed/incomplete speech development) similar to ASD but milder.
  • Older parents and multiple births increase ASD risk.

Although ASD has a genetic basis, there are also environmental and physical health factors that ultimately determine whether a child has ASD, how severe the case is, and whether early intervention can partially reverse impaired social and communication skills. It is in this realm that natural medicine can help.


Multiple causes

ASD can only be treated as a complex, multifactorial disorder; a single gene defect or environmental exposure cannot be held accountable except in a minority of cases.

Certainly there are individual cases in which children appear to react to vaccines. Some of the possible reasons are discussed below. It’s also an issue of chronology. Vaccines are given at ages which coincide with neurodevelopmental milestones, so if a child does not reach a given milestone, it might be easier to believe that a reaction to the vaccine is at fault.


Possible causes

Now let’s consider some of the environmental and physical health factors that may cause or contribute to ASD. These areas may not be relevant to many ASD children but should still be investigated.

Food allergies

ASD children often refuse all but a few foods. Unfortunately, this repetitive diet is a disaster if the child is allergic to some of these frequently consumed foods.

Limited research has shown that ASD can be linked to severe type II (nonanaphylactic) food allergies to casein (a cheese protein), milk, and other dairy products; soy; wheat; chocolate; and food additives and preservatives.

Food allergy testing is strongly recommended; if this is not possible, then no matter the fuss, start removing potential allergens from the diet, one by one.

Gastrointestinal disorders

Some studies have found an increased incidence of chronic stomach cramps, diarrhea, constipation, gastroenteritis, and colitis in ASD patients. The damaged and inflamed bowel may become overly permeable which allows toxins, pathogens, and incompletely digested foods access to the bloodstream. In genetically susceptible individuals, this is tantamount to poisoning.

Food allergies may be related by causing both gastrointestinal and sinus-nasal symptoms. The upper respiratory congestion leads to frequent infections which are treated with antibiotics. This in turn stimulates yeast (Candida) overgrowth which then exacerbates the allergies and gastrointestinal symptoms. It’s important to note that children with compromised gut immunity may have strong reactions to vaccines.


Other possible causes of autism

Chronic brain inflammation

Reduced blood flow to key areas in the brain is common in ASD children. This reduction causes low oxygen levels, known as “brain hypoxia.”

Chronically suboptimal glucose and oxygen flow to a given brain region causes reduced activity in that region which can translate to abnormal or dysfunctional behaviour.

Hypoxia also reduces brain cell repair and metabolic cleanup functions, resulting in brain tissue inflammation. Conversely, inflammatory conditions of the vascular (circulatory) system may be causing the reduced blood flow in the first place.

Regardless, children with existing brain inflammation/hypoxia can be expected to have abnormal, hyperinflammatory reactions to vaccines, possibly even resulting in autoimmune attacks on their own tissue, similar to rheumatoid arthritis.

Testing the effects of increased oxygen on brain activity in autistic children, a 2009 controlled study of 62 ASD children found that 40 sessions in a hyperbaric chamber markedly improved social and cognitive behaviour. The hyperbaric chamber used 24 percent oxygen at 1.3 atmospheres.

It’s known through studies with sports and trauma injuries that hyperbaric treatments rapidly reduce brain inflammation. Whether a four-week treatment will result in permanent improvement, or whether ongoing treatment will be necessary, isn’t yet known.

Mitochondrial disease

In some cases ASD may be linked to a mitochondrial disorder. Mitochondria are the power plants of our cells, breaking down to provide energy for all muscular contractions and most cellular activities.

Parents of an ASD child who tires easily; is averse to exercise; and who has gross motor dysfunction, movement disorders, seizures, or a family history of mitochondrial disease should suspect mitochondrial disorder and consult a specialist.

I would urge any parent who observes social disinterest and delayed motor and/or language development in their infant to consult a professional quickly. Intensive programs for higher functioning ASD children can help provided they’re implemented at an early age.


Vaccine/ASD link

The controversy surrounding ASD and the measles-mumps-rubella (MMR) vaccine and mercury preservatives used in other common infant vaccines continues unabated in the media.

The issue, however, has been extensively researched and no causal link has been proven. A February 2009 special US federal court also ruled that there was no proven link between certain early childhood vaccines and autism that developed in children involved in the case.

Some additional points to consider:

  • Boys and girls are both vaccinated, yet ASD is much rarer in females.
  • Infant/toddler immigrants from countries with entirely different vaccination schedules have the same incidence of ASD as native-born North American children.
  • Large epidemiological studies of MMR and ASD incidence done in the US, UK, Finland, and Denmark have all failed to show an association between MMR and ASD.
  • The authors of the original paper proposing a link between MMR and ASD have acknowledged errors in their methodology and retracted their original research paper.
  • Mercury preservatives have been discontinued in North America since 1996 to 1999, depending on the specific location and vaccine type, yet ASD incidence continues to rise. Further, unlike the US, Canada never used mercury preservative in the common diphtheria-pertussis-tetanus-hepatitis (DTP or DTPH) vaccine.
  • A 2006 study of 27,749 Montreal school children identified groups of children with high, intermediate, low, and nil exposure to vaccine mercury. There was no relation between pervasive developmental disorders and mercury exposure. The most recent birth group was given mercury-free vaccinations, plus had a lower rate of total students vaccinated, yet had an increased incidence of developmental disorders.


Gluten-casein connection

Research suggests that digesting certain proteins, such as gluten and casein, may be a problem for some people with autism.

According to the Autism Society of Canada, “higher-than-normal levels of certain peptides have been found in the urine of children with autism, suggesting an incomplete breakdown of these proteins into amino acids.

“Since over-absorption of peptides affects brain function, removal of these proteins from the diet is thought to be the only way to prevent further neurological and gastrointestinal damage.”


Gluten-containing foods

  • wheat and wheat products
  • oats
  • rye
  • barley
  • bulgar
  • durum
  • kamut
  • spelt
  • food starches
  • semolina
  • couscous
  • malt
  • some vinegars
  • soy sauce
  • flavourings
  • artificial colours
  • hydrolyzed vegetable proteins


Casein-containing foods

  • milk
  • cheese
  • butter
  • yogourt
  • ice cream
  • whey
  • some brands of margarine
  • may be added to nonmilk products such as soy cheese and hot dogs in the form of caseinate


Foods that can safely be eaten on a gluten-free, casein-free diet

  • rice
  • quinoa
  • amaranth
  • potato
  • buckwheat flour
  • soy
  • corn
  • fruits
  • oil
  • vegetables
  • beans
  • tapioca
  • meat
  • poultry
  • fish
  • shellfish
  • teff (a wheat alternative)
  • nuts
  • eggs
  • sorghum


No Proof

No Proof

Matthew Kadey, MSc, RDMatthew Kadey, MSc, RD