Elevated Levels of Toxicants Found in Teeth of Autistic Children

A pilot study from the University of Texas San Antonio (UTSA) Health Center adds to existing bodies of evidence that link exposure to toxicants such as pesticides, flame retardants and plastics with neurotoxicity and autism. Researchers found that the primary teeth of children with autism had elevated levels of toxicants compared to the primary teeth of children without autism.^{1 2}

Prior studies have looked at chemicals in urine and blood samples, offering a snapshot of short-term exposure to toxicants. But UTSA researchers wanted to look deeper at cumulative toxin exposures. Because primary or baby teeth form over a span of over three years, including time in utero, teeth can tell a different story than urine and blood samples. Teeth begin forming in utero around the 14^th week of pregnancy and are fully formed by age three. As the teeth develop, they can incorporate various chemicals from the mother’s and baby’s environment, creating a record of chemical exposure over a span of years.

Scientists examined shed primary teeth and found an average of 300 chemicals per participant in both autistic and typically developing children. Of 60 chemical compounds identified, 95 percent demonstrated higher concentrations in the autism group, with 19 of those concentrations being “significantly higher.”

Thirty-nine of the 60 compounds detected are also known developmental toxicants or endocrine-disrupting compounds including benzyl benzoate, a food and fragrance preservative, and organophosphate esters frequently found in flame retardants and products that may be applied on the skin. The researchers noted that five of the top nine compounds that were found elevated in children with autism migrate from baby bottles, diapers, and food packaging.¹

Researchers noted that “many of these toxicants target the brain, liver, and mitochondria.”¹

Study Highlights Importance of Recognizing Environmental Triggers in Autism

Autism was once a rare condition, but prevalence has risen over 300 percent in the past two decades. While autism has both genetic and environmental determinants, the drastic increase in autism rates highlights the importance of looking at environmental triggers alongside genetic susceptibility.

Multiple classes of chemicals have been implicated in autism including medications; vaccines with heavy metals such as aluminum and mercury; arsenic, lead and pesticides,  plasticizers, as well as compounds that make materials more pliable such as phthalates, PVC, and phosphates.¹

The UTSA researchers referenced a 2011 study that reported substantially lower genetic estimates involved in autism and found that shared environmental factors contributed nearly as much variance as genetic factors. “This study is widely recognized for demonstrating that environmental influences are more substantial than previously assumed,” researchers noted.¹

Safety Research Can’t Keep Up With Rate of Chemical Development and Use

Chemicals are being developed faster than the scientific research needed to evaluate them, noted Gimeno Ruiz de Porras, PhD, a social and occupational epidemiologist at UTSA. “There are hundreds of millions of compounds being produced and released into commercial use,” he said. “Industry is moving much faster in producing chemicals for different uses than we can study them.”¹

A major concern for exposure to toxicants for babies and young children is the timing of exposure with crucial brain development. Toxicants or endocrine disruptors can affect biological processes involved in development, including affecting the mitochondria and cellular function.

“There are several critical windows of exposure during pregnancy, especially in the first trimester, but it doesn’t stop there,” lead researcher Lynne Heilbrun, MPH said. “The central nervous system continues to develop after birth until around age 25.”¹

Many experts and medical organizations maintain that while the autism rates have increased from one in 150 children in the year 2000, to one in 31 children in 2022, the main contributing factor to the autism epidemic is due to changes in screening and diagnostic criteria.³

CDC to Award Contract to Investigate Link Between Autism and Vaccination

Last year, the U.S. Centers for Disease Control and Prevention (CDC) announced a contract awarded to Rensselaer Polytechnic Institute to investigate links between autism prevalence and contents of vaccines.⁴

Juergen Hahn, PhD, would be the principal investigator if the company accepts the contract, a spokesperson said. Dr. Hahn is an RPI professor of biomedical engineering who has done extensive research surrounding autism. His work includes an experimental blood test that he says can detect autism in 96 percent of children. He also authored a 2017 paper that found statistical associations between heavy metals and autism.⁴

In December 2025, the World Health Organization (WHO) reaffirmed its stance that vaccines do not cause autism and that the “most robust scientific evidence consistently rejects a causal link between vaccines and ASD.” The WHO does recognize the role of genetics, environmental toxins, and heavy metals in the role of autism.

The American Academy of Pediatrics (AAP) also denies a role of vaccines in autism, but states that severe maternal immune responses, certain medications, and environmental factors influence a child’s risk of developing autism.⁵

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