Traditionally, the diagnosis of autism has been based on the observation of behavior, and treatment focused primarily on alleviating challenging behaviors. However, there is a very real biomedical component to the disorder in which underlying medical issues often cause or contribute to autistic behavior. Some of the most common problems include gastrointestinal (GI) overgrowth of Candida and Clostridia, inability to detoxify environmental toxins, and development of food intolerances and/ or allergies. These physical and environmental factors limit the nutrients available to the brain and body, resulting in damage to cellular, metabolic, and central nervous system functionality.

Genetic susceptibility to autism may determine who develops this complex disorder, but nutrient deficiencies and food allergies strongly influence the severity of symptoms. Exposure to toxins and imbalanced microbial growth in the GI tract contribute to pathological responses to food. Yeast (most commonly, Candida), parasites, viruses, and bacteria, particularly Clostridia, all have the potential to act as pathogens. Eradicating harmful and often recurrent intestinal microbes and restoring proper intestinal flora balance is the best place to start so the body can begin to heal and detoxify itself. Eliminating IgG-reactive foods which can contribute to inflammation is an important part of healing the