Major areas that have raised suspicion among affected families and professionals that deal with Autism include vaccine related effects, heavy metal exposure, yeast overgrowth in the intestinal system, poorly metabolized toxic proteins, and others yet to be defined. Each of these areas has some support but not yet definitive evidence of causation.

Because of the fact that several vaccines are given early in a child’s life, these have been implicated for a possible environmental trigger for Autism. In addition, there is some medical evidence that this could be the case. Research has found clusters of measles virus in enlarged lymph tissue of the intestines in patients with autism and developmental delay, which poses a possibility that a component of the MMR (Measles-Mumps-Rubella) vaccine could be involved. Other investigators likewise have suspected that Rubella virus could be at play, but with less evidence available. Despite this possibility, the effects of these viruses on a child without the vaccine can likewise cause encephalitis and other significant health problems. Therefore avoidance of this vaccine is a serious risk.

A more significant vaccine related possibility is the effect of Thermosal on the developing brain. This compound is a preservative used previously in many vaccines in various amounts. It is metabolized to ethyl mercury, which has been touted as a possible toxin. There is evidence that children with Autism have less mercury in their hair follicles, and other tissues, that normally excrete mercury from our bodies. Likewise, when given an agent to chelate, or bind, the mercury, some studies show children with Autism excrete larger amounts than normal in response to this in their urine. These factors have led some to believe that there is an inherent problem with mercury metabolism in these individuals, and that it builds up in the body exerting toxic effects. The addition of hepatitis vaccines and chicken pox vaccines in recent years to the previous baseline of childhood immunizations could reflect why an increase in incidence of Autism may have occurred. In the last few years there has been a push to establish vaccines without Thermosal, but even in those vaccines that report none present, some have still shown trace amounts.

Other extrinsic factors that have been suspected include food proteins that may also result in a toxic effect on the developing brain when these are poorly metabolized. The restriction of gluten (which is a protein found in wheat related products) and casein (a milk based protein) in the diet unquestionably has improved many children with Autism. Both of these proteins represent psycho-active proteins (gluteomorphines and caseoproteins) that yield effects on various opiate receptors in the brain and nervous system. These receptors are likewise in other areas of the body, including the intestine. Due to a proposed inability to digest and metabolize these proteins normally, or possible an intolerance to stimulation of these opiate receptors, autistic patients subsequently have detrimental effects in cognition, behavior, etc. Similarly, other professionals treating Autism believe toxic byproducts of yeast organisms in the gut result in deleterious effects, and restrict foods that are high in yeast organisms and also employ a medicine Nystatin for periods of time. There are several studies and anecdotal reports that this results in significant functional improvement in many patients.

Genetic influences have already been discussed, but how these genetic predispositions result in vulnerability is a large question. Outside the environmental or extrinsic factors listed, there are possibly factors awry within the body that may cause developmental delay as well. Some of these include essential fatty acids, Vitamin B6, magnesium, oxidative stress, and serotonin and dopamine metabolism.

Essential fatty acids are included in fats that we get from our diets. With more processed food, and less fresh fruits, meats and vegetables, the type of fatty acids we get from our diet has changed. Of the essential fatty acids, Omega 6 and Omega 3 fatty acids are most common. In children with Autism, there is evidence that they have a lower than normal level of these fatty acids. This may be due to defective fatty acid metabolism. Omega 3 has been shown to be effective in lowering atherosclerosis risk as well, and the goal with supplementation is to increase the ratio of omega 3 to omega 6 intake while increasing overall essential fatty acid intake. Improvement in function has been reported in some patients with this dietary change.

Also, Vitamin B6, or pyridoxine, clearly has been shown to help symptoms and features of autistic children, and this is even more pronounced when given with magnesium. The proposed reason for this is that Vitamin B6 is converted to pyridoxal-5-phosphate which is an important coenzyme in the dopamine metabolic pathway. Some children with Autism have been shown to have higher than normal excretion of dopamine byproducts and also have higher levels of serotonin. Both of these are key neuro-transmitter proteins involved in many brain processes, including the limbic system functioning. By giving higher supplementation of Vitamin B6 and magnesium, it is proposed that flooding a defective metabolic enzyme system may allow it to function more optimally and improve symptoms. There are other coenzymes that also may be helpful and include Vitamin C, tetrahydrobiopterin, and S-adenosyl methionine (SAM).

Lastly, there are also studies that support children with Autism suffer from an increased amount of oxidative stress. This refers to a higher risk of having tissue damage from normal metabolic byproducts that may be toxic if not “absorbed”. In examinations of groups of autistic individuals, some have shown lower levels of normal inherent anti-oxidant chemicals, which assumes they are lower because of a higher amount of free radicals and oxidative stress chemicals in their body. In this regard, antioxidants like Vitamin A, Vitamin E, Vitamin C and selenium may be helpful adjunctive agents.