Baby teeth link autism and heavy metals.

• Position: Fetal Development

Baby teeth from children with autism contain more toxic lead and less of the essential nutrients zinc and manganese, compared to teeth from children without autism, demonstrates a study led by Manish Arora, environmental scientist and dentist at the School of Medicine at Mount Sinai, New York. The findings, published in Nature Communications, suggest that differences in early-life exposure to metals or, more importantly, how a child's body processes them, may affect the risk of autism.

The differences in metal uptake between children with and without autism especially were notable during the months just before and after the children were born. The scientists determined this by using lasers to map the growth rings in baby teeth generated during different developmental periods.

The researchers observed higher levels of lead in children with autism throughout development, with the greatest disparity observed during the period following birth. They also observed lower uptake of manganese in children with autism, both before and after birth. The pattern was more complex for zinc. Children with autism had lower zinc levels earlier in the womb, but these levels then increased after birth, compared to children without autism.

The researchers note that replication in larger studies is needed to confirm the connection between metal uptake and autism.

"We think autism begins very early, most likely In the womb, and research suggests that our...