The National Institutes of Mental Health announced yesterday that it was canceling a study that aimed to study chelation therapy for children with autism.

As we noted in an article a few weeks ago, several scientists and experts publicly questioned the study, saying that it would have been unethical and unsafe.

I guess the National Institute of Mental Health came to the same conclusion. “We recognize that for children there is a fine line for the risk-benefit ratio,” the institute’s scientific director Richard Nakamura told the Associated Press. “You have to be pretty certain of the overall safety of the procedure.”

Researchers at the institute had initially defended the study saying chelation is widely used to treat children with autism as many as 1 in 12 children, according to one estimate and the study might prove to parents that chelation is of no benefit.

The researchers had planned to recruit 120 children with autism and inject half with dimercaptosuccinic acid (DMSA), which would remove mercury and other heavy metals from the body.

DMSA and other chelating agents are known to be harmful one study in rats showed that DMSA affects brain function so some experts said studying chelation puts children needlessly at risk. Even if the study proves chelation doesnʼt work, they said, itʼs hardly likely to dissuade parents who believe in it.