What Twins’ Baby Teeth Are Telling Us About ADHD and Autism

A research team in Sweden, looking for a way to test a hypothesis about the effects of chemical exposure on fetal neurological development, recently enlisted an unusual assistant: The Tooth Fairy.

Not really, of course. But the team did collect naturally lost baby teeth from sets of twins (and one set of triplets) in order to analyze their chemical makeup.

Teeth are formed in a growing fetus in the same way that trees grow—layer by layer, ring by ring, using the materials available to create new cells at the time. And like tree rings, these rings then preserve a permanent record of baby’s earliest biological processes. That includes how the developing fetus metabolizes nutrients and toxins that can affect the nervous system and the developing brain.

The first study using laser technology to map unusual metabolism of heavy metals in baby teeth in 2017 tied excessive levels of zinc and manganese in baby teeth to risk of autism, noting “differences in early-life exposure to metals, or more importantly how a child’s body processes them, may affect the risk of autism.”

But the new study goes farther, and it may demonstrate that lifelong neurological information processing and relational differences may originate in the womb. Critically, this does not mean Mom is to blame, as Craig Newshaffer, Ph.D. (dean for research at Drexel University Dornsife School of Public Health and lead investigator of many publicly funded autism studies) points out in his webinar on environmental autism risk factors.

Now it turns out ADHD may be similarly mediated by infant development in the womb.

Chemicals Are Everywhere; It’s How They’re Metabolized That Matters

It is nearly impossible to eliminate in-utero exposure of the developing fetus to chemicals and other potential environmental neurotoxins. That’s because one baby may metabolize incoming materials “typically,” while another may not.

The latest findings from teeth and twins demonstrates how complicated the equation really is.

In some twin pairs, one sibling displays clinical symptoms of ADHD (attention deficit/hyperactivity disorder) while another is neurotypical; in others, one has ADHD while the other has been placed on the autism spectrum; some twin pairs have received “comorbid,” or combined, diagnoses. And their baby teeth matched these diagnoses, showing clear correlations in how their developing bodies had metabolized zinc and copper while those teeth were forming.

The children who presented with ADHD had baby teeth that showed their early metabolism of several heavy metals was atypical: Specifically, their teeth showed reduced “cycle” processing for cobalt and vanadium. While the current study is early research designed to spur future development of early detection and potential treatment, the authors discussed the larger implications for people living with such conditions briefly: “With more research, this could lead to an early detection tool, which could mean early treatment, which could potentially mean a better life outcome,If there’s a critical time when these metals get dysregulated, maybe we can counter that.”

The researchers found significant dysregulation, or differences in metabolic rhythms, in children whose brains show patterns of neuratypcial function. And those metabolic signs were recorded in baby teeth formed during their fetal development.

The Oral-Systemic Connection Writ Large

As I reflected on this latest finding when it arrived in my inbox I could not help but recognize it as yet another example of the convergence of our understanding of human health as a vast, complex, interconnected system.

We speak a great deal in dentistry and medicine of the oral-systemic connection. This emerging novel research avenue wraps it up in a bow by showing how deeply everything within the human body is connected, and there is still so much to learn. As a pharmacist, I’ve been acutely aware of individual (genetic) differences in response to prescription drugs for years; seeing solid evidence behind these phenomena preserved in dentin is one of the most astonishing, rewarding, exciting developments of the past twenty years, with potential for untold future advances in personalized and genomic-based medicine.

Pharmacy, nutrition, dentistry, medicine, kinesiology, metabolic medicine; all of the healing and caring disciplines are interconnected with our metabolic processes. While it is still early days in this kind of research. Boundaries are as fluid (and sometimes as artificial) as the blood-brain barrier and the oral-cardiac barrier.

When twins’ baby teeth can tell us what bodies were doing as their neurological systems were being formed, entire new horizons for whole-person health research and care are opening before our eyes.