More Research Connects Toxic Metals to the Development of Autism

January 10, 2022

Study Shows Children with ASD Had Higher Metal Levels in Urine, Blood and Hair Samples


A new systematic review suggests that a high body burden of toxic metals is associated with autism. This review consisted of 6 studies and included 425 participants (226 children with autism and 129 controls.) The reviewed studies detailed higher levels of aluminum, arsenic, barium, chromium, cadmium, cerium, lead, mercury, thallium, tin, and tungsten in urine samples of children on the spectrum compared to neurotypical controls. Blood samples from children with autism showed higher levels of lead but lower levels of cadmium compared to controls. Arsenic, cadmium, barium, cerium, and lead were also found in higher levels in hair samples of children on the spectrum. One of the reviewed studies determined that high lead levels in hair samples significantly correlated with a negative intelligence quotient. Additionally, the same study suggested that lead enhances adverse inflammatory responses and/or autoimmunity, which can be major symptoms of autism. Results of mercury load in hair samples were intriguing. One study showed mercury levels in hair samples of young children with autism were lower, while older children had higher levels than their corresponding controls, which suggest that mercury metabolism can fluctuate with age. Another study demonstrated that lower levels of mercury were found in hair samples from children with autism compared to controls. The authors of this study believe these lower levels are due to poor detoxification and excretory capacity. Overall, the review’s authors concluded that high toxic metal levels correlate positively with symptoms of autism. They believe this is attributable to poor detoxification and excretory capacity in individuals with autism which leaves them more vulnerable to the toxic effects of heavy metals compared to neurotypical individuals.

Original Study Abstract

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