Autism and the Environment
Autism has long been considered an incurable genetic disorder specifically targeting the brain. The rapid rise in diagnoses of autism, the whole-body symptoms of autism and the ability of many to improve are now challenging this model. Genetics alone cannot account for the huge increase in new diagnoses. A static brain disorder does not encompass common problems seen in the gut, immune, allergic response and systemic metabolic changes of people with autism. “Incurable” does not capture how people with autism can improve substantially. The new model of autism is a whole-body condition, with both genetic vulnerabilities and environmental triggers contributing to its expression.
Currently 1 in 150 children who are born will be diagnosed with an autism spectrum disorder (ASD).[Centers for Disease Control Mortality and Morbidity Weekly Report, 2/9/2007]) This rapid rise within one generation is greater than genetic evolution can explain and suggests that there is more than genetic interactions at play. There may be several or even many underlying factors contributing to ASD. The impact of an increasing amount of environmental triggers, coupled with genetic vulnerability, could explain the dramatic global increases in the rates of ASD.
A Link Between Toxins and Autism?
Although there is still much research to be done, current studies suggest a link between environmental exposure to certain toxins (e.g., heavy metals, such as mercury and lead; household plastics; and chemicals, such as pesticides) and the soaring rates of autism in our population. These toxins are more prevalent today than in the past. Those with ASD, or at risk for ASD, may be especially vulnerable to them. For example, many children at risk of developing autism may have a metabolic impairment that reduces their ability to metabolize and detoxify, so that they have trouble ridding their bodies of heavy metals and other toxins. Build up of these toxins in the body can lead to brain and nervous system damage and developmental delays, and can chronically affect brain function and reduce health and well-being throughout life.
Toxins and other environmental factors can contribute to autism at various points in an individual’s development. Toxins don’t have to kill people or cells in their bodies to cause harm. They can change how the brain and body develop, and how they function.
Toxic exposures before birth can affect the development of the brain and nervous system, as well as other systems of the body. After birth, they can affect later stages of development. Exposures at any point can affect the health of the cells in our body, which can lead to loss of health and development of disease.
If toxins alter the health or function of cells in our brains, the cells may not be able to work so well in helping us to use our brains. Our brains may get more “irritable.” This can cause changes and problems in the way we think, learn, process sensory information, sleep and handle stress.
Toxins are a lifelong problem, not just a developmental problem. Many people with autism are very sensitive and reactive to exposures throughout life. They can have ups and downs that can be traced not just to stress but also to chemicals and allergens.
Research dollars have only recently started to support the systematic evaluation of environmental toxins as possible risk factors for ASD. No “single cause” has emerged. One reason is that many potential contributors to autism can have similar effects. Many different kinds of chemicals can impact similar vulnerable parts of our systems. Also, many different genes can target the same or related pathways.
Because many seemingly environmental and genetic risks converge, no single cause of autism may ever jump out at us from the data. Instead, we need to take seriously the potential harm that can be caused by various combinations of factors, even if there is no single one responsible.
Reprinted with the permission of the Autism Society.