Scientists Find Higher Levels of Potentially Toxic Chemicals in Baby Teeth of Children With Autism
Scientists have identified significantly higher levels of several potentially toxic chemicals in the baby teeth of children with autism, suggesting that early-life exposure to common environmental substances may play a role in autism risk.
The findings come from a small but detailed pilot study and do not establish that these chemicals cause autism. However, they raise further questions about whether substances found in household products, food packaging and personal care items may contribute to developmental vulnerabilities.
Baby teeth as exposure archives
Most studies investigating environmental chemicals rely on blood or urine samples, which reflect exposure over relatively short periods. Baby teeth, however, begin forming around the fourth month of pregnancy and continue developing through approximately age three, preserving a layered record of early chemical exposure.
Researchers from the University of Texas at San Antonio and collaborating institutions analyzed naturally shed primary teeth from 38 children, including 22 diagnosed with autism and 16 without the condition. The teeth were cleaned and examined using advanced chromatography and mass spectrometry techniques.
This method enabled researchers to identify hundreds of compounds at extremely low concentrations. The teeth served as biological time capsules, preserving traces of substances absorbed during pregnancy and early childhood, when the brain and nervous system undergo rapid development.
Hundreds of toxicants detected
On average, each tooth sample contained more than 300 chemical toxicants. Researchers then concentrated on 60 compounds detected in at least half of the participants, allowing them to compare exposure patterns between children with and without autism.
Approximately two-thirds of these 60 substances are classified by the US Environmental Protection Agency as developmental or reproductive toxicants or endocrine-disrupting compounds. These classifications include chemicals known or suspected to interfere with hormonal activity, organ development or reproductive health.
Among the 60 compounds examined, 95 percent were present at higher concentrations in the teeth of children with autism. Nineteen chemicals showed statistically significant differences between the groups, suggesting that the observed disparities were unlikely to result from chance alone, despite the relatively small sample.
Everyday products under scrutiny
The chemicals found at elevated levels in children with autism originated from a variety of sources. They included organophosphate esters used as flame retardants, benzoic acids and esters, phthalates commonly associated with plastics, salicylates, aromatic ketones, ethers and caprolactam, a substance used in nylon manufacturing.
One particularly notable finding involved benzyl benzoate, an ingredient used in certain personal care products, as a food additive and in treatments for lice and scabies. Concentrations of this compound were more than seven times higher in the teeth of children with autism than in those of the control group.
Researchers also identified 11 chemicals in baby teeth that previous studies have shown can migrate from baby bottle components. Other detected substances are known to leach from pacifiers, food-contact materials, cross-linked polyethylene (PEX) water pipes and indoor furnishings.
What the study does and does not show
The authors emphasize that their findings do not demonstrate a causal relationship between any individual chemical and autism. Autism is widely understood as a complex condition shaped by genetic and environmental influences that may interact throughout development.
Nevertheless, the results contribute to growing research examining whether prolonged, low-level exposure to multiple chemicals could influence fetal and early brain development. Many of the identified toxicants are known to affect the brain, liver or mitochondria, providing possible biological pathways through which exposure might influence neurological outcomes.
Because the research was a pilot study involving only 38 children, larger and more diverse groups will be necessary to verify the findings. Future investigations must also determine which combinations of chemicals and exposure periods, if any, are most relevant to autism risk.
Implications for families and policy
The study adds to calls for a precautionary approach to chemical exposure, particularly during pregnancy, infancy and early childhood. The researchers argue that limiting unnecessary contact with potentially harmful substances should become a public health priority.
Suggested precautions include choosing fragrance-free personal care products, reducing plastic use during food preparation, avoiding heating food in plastic containers and checking product labels for known endocrine-disrupting chemicals whenever possible.
Regulatory agencies around the world are already reviewing many of the substances highlighted in the research. Updated safety standards for baby products, food packaging and water infrastructure could eventually reduce background chemical exposure across the wider population.
As scientists continue improving methods for analyzing baby teeth, these small biological samples may become valuable tools for understanding how early environmental exposures interact with genetics to influence lifelong health, including the likelihood of developing autism.
