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Dental biorhythms track weight gain in adolescents

Monday 29 August 2022 1:50pm

Growth lines in baby teeth indicate weight gain during early adolescence, a group of international researchers have discovered.

The lines are biorhythms – markers of the body’s biological clock which controls many aspects of the metabolism.

Carolina Loch image
Dr Carolina Loch

University of Otago’s Dr Carolina Loch, of the Faculty of Dentistry, says all aspect of the body’s metabolism have a clock, some things have a 24-hour circadian rhythm while others have near weekly rhythms.

“We have a marker of this biological clock in days imprinted inside the milk teeth,” Dr Loch says.

“This relates to many aspects of our metabolism, not only tooth growth.”

The study, published in Communications Medicine, found adolescents with a faster dental biorhythm (five or six-day cycle) weighed less, gained less weight, and had the smallest change in their body mass index over 14 months.

Those with a slow biorhythm (seven or eight-day cycle) produced the greatest weight gain.

“Less growth lines equal a faster biorhythm and a faster metabolism.”

Dr Loch says the results are unique.

“They show a previously unknown link between markers of biorhythms in teeth – similar to the growth rings we see in trees, our teeth also show a similar structure – and weight gain,” Dr Loch says.

The research team was led by Dr Patrick Mahoney, of the University of Kent, and involved researchers from the University of Auckland, Harvard Medical School, and The Ohio State University.

Dr Loch was responsible for the New Zealand section of the project, assisted by Otago’s Assistant Research Fellow Sophie White.

They collected shed baby teeth and took monthly weight, height, and lower leg length measurements of 125 children in 19 Dunedin schools.

“While teeth were also collected in other centres (UK, USA and France), the New Zealand arm of the project was unique because we were actually collecting growth data from living participants.”

One surprising find was participants with slower biorhythms were six times more likely to have a very high body mass index.

“Although development of obesity is a multifactorial process and will depend on lifestyle, socioeconomic, and psychological factors, we show baby teeth can be a biological marker for predisposition to greater weight gain in early adolescence, many years before the health risks associated with obesity will develop.”

Dr Mahoney says the research is an exciting first step.

“The next step is to determine if the link we have discovered extends to related adverse health outcomes for adults,” he says.

“Potentially, milk teeth may hold a record of this information many years before those outcomes can manifest in adults.”

Publication details:

Dental biorhythm is associated with adolescent weight gain

Patrick Mahoney, Gina McFarlane, Rosie Pitfield and Alessia Nava of the University of Kent, Carolina Loch and Sophie White of the University of Otago, Bruce Floyd of the University of Auckland, Erin C. Dunn of Harvard Medical School, and Debbie Guatelli-Steinberg of The Ohio State University.

Communications Medicine

DOI: https://doi.org/10.1038/s43856-022-00164-x

For more information please contact:

Dr Carolina Loch
Sir John Walsh Research Institute
Faculty of Dentistry
University of Otago
Email carolina.loch@otago.ac.nz

Jessica Wilson
Adviser Media Engagement
University of Otago
Mob +64 21 279 5016
Email jessica.wilson@otago.ac.nz