Human primary teeth have a biorhythm that has been linked to adolescent weight gain, according to research from the University of Kent.
The biorhythm in primary “milk” molars (Retzius periodicity [RP]), discovered by an international research team led by Dr. Patrick Mahoney at Kent’s School of Anthropology and Conservation, is linked to certain physical development processes during early adolescence. A faster dental biorhythm resulted in smaller weight and mass gains.
RP develops through a process that is similar to the circadian rhythm, with a repeat interval that can be measured with a resolution of days. The rhythm, which corresponds to the period when tooth enamel forms, is constant in the permanent molars of individuals who do not still exhibit symptoms of developmental stress. Although it can range in length from five to twelve days, the human modal RP has a nearly seven-day cycle.
Researchers found that, over a 14-month period, adolescents with a faster biorhythm (five or six-day cycle) weighed less, gained less weight, and had the smallest change in body mass index. This study was the first of its kind, and it was published in Communications Medicine. The people with slow biorhythms gained the most weight (seven or eight-day cycle).
For more than a century, dental histologists have been aware of the biological rhythm, but it wasn’t until recently that studies comparing various mammalian species revealed its importance for body mass and growth. Recently, research was conducted on the significance of rhythm to humans.
Slower biorhythm participants were six times more likely to have a very high BMI, which was unexpected. Adolescence is characterised by rapid changes in body size, but excessive weight gain during puberty can have negative health consequences, including adult obesity.
Dr. Mahoney underlined, “This 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. Potentially, milk teeth may hold a record of this information many years before those outcomes can manifest in adults.”
The project’s histologist, Dr. Gina McFarlane, who is also based at Kent, stated, “Our findings provide a new avenue from which to explore links between overweight children and adult health risks. Milk teeth are naturally exfoliated (drop out) during the childhood years. These discarded teeth contain precise information about a fundamental growth rhythm that we now know tracks adolescent weight gain.”