A study of mercury levels in the baby hair of children who were later diagnosed with autism has produced startling results. The babies had far lower levels of mercury in their hair than other infants, leading to speculation that autistic children either do not absorb mercury or, more likely, cannot excrete it.
Autistic children, according to this line of thinking, may be deficient in processing zinc, iron and copper and other metals essential for brain development.
The research, led by Louisiana doctor Amy Holmes, will be published in September in the International Journal of Toxicology, New Scientist said.
They compared mercury levels in hair that had been kept from 139 babies when they had their first haircuts, when they were around 18 months old.
Mercury levels among 94 children who were later diagnosed as autistic was 0.47 parts per million (ppm), while among the 45 other children who developed normally, the levels were eight times higher, at 3.63 ppm.
The lower the level of mercury, the worse the degree of autism, the scientists found.