Toxic trace elements in the hair of children with autism.
Hair tests for toxic metals do not give clear answers about autism and should not guide treatment.
01Research in Context
What this study did
Researchers compared hair samples from children with autism and matched controls. They used lab machines to measure lead, mercury, and uranium levels. The study asked: do autistic kids carry more toxic metals in their hair?
What they found
Children with autism had higher hair levels of lead, mercury, and uranium. The differences were statistically significant. Still, the authors warned the finding is not ready for clinical use.
How this fits with other research
De Palma et al. (2012) used the same hair test and found almost no link between metals and autism. Their larger review showed only a tiny lead effect. The clash looks big, but both labs used different control groups and cutoff rules.
Giesbers et al. (2020) saw the opposite trend in Jamaican kids. Higher metal exposure was slightly less common in children with ASD after adjusting for diet. Geography, food sources, and pollution levels likely explain the flip.
Kydd et al. (1982) asked the same question decades earlier and also found no real mineral differences in hair. The 2005 positive signal has not repeated well.
Why it matters
Hair mineral tests are tempting because they are cheap and non-invasive. Yet most follow-up studies show they cannot reliably flag autism or guide treatment. Save your clinical hours for evidence-based assessments and skip this test unless you are running a research protocol.
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02At a glance
03Original abstract
Excess or deficiency of natural trace elements has been implicated in the etiology of autism. This study explores whether concentration levels of toxic metals in the hair of children with autism significantly differ from those of age- and sex-matched healthy controls. In-hair concentration levels of antimony, uranium, arsenic, beryllium, mercury, cadmium, lead and aluminum from 40 boys with autism and 40 healthy boys were determined by Perkin-Elmer mass spectrometry. The children with autism had significantly (p<0.001) higher in-hair concentration levels of lead, mercury and uranium. There was no significant difference between the two groups in the other five toxic elements. The ratio between nutritional elements and toxic metals among children with autism was within the normal range. The possible sources of the toxic metals are discussed. Such testing is informative but at present the practical implications in terms of diagnosis and clinical management are limited.
Autism : the international journal of research and practice, 2005 · doi:10.1177/1362361305053255