A new way of looking at tooth enamel could give scientists a path to deeper understanding of the health of human populations, from the ancient to the modern.
The method developed by US scientists—and published in the Journal of Archaeological Science—examines two immune proteins found embedded in human tooth enamel: immunoglobulin G, an antibody that fights infection, and C-reactive protein, which is present during inflammation in the body.
“These proteins are present in tooth enamel, and they are something we can use to study the biological and potentially the emotional health of past human populations,” lead author Associate Professor Dr Tammy Buonasera at the University of Alaska said.
“Analysis of immune proteins in enamel has not been done before and this opens the door to studying disease and health in the past in a more targeted way than we can today.”
A/Prof Buonasera and collaborators tested for the presence and amount of the proteins in tooth enamel from three groups of people:
- Ancestral Ohlone people from a mission outpost dating to the late 1700s and early 1800s in the San Francisco Bay Area.
- European settlers from the late 1800s buried at a San Francisco city cemetery.
- Modern-day military cadets who donated wisdom teeth.
The research team then cross-referenced the levels of the two proteins with the known history and experiences of each of the populations.
The researchers found a close correspondence between evidence for high levels of stress and disease in the Indigenous population and high levels of the two proteins in their teeth. Protein levels were much higher than those in the other two groups tested.
“We see certain individuals, especially children, with very high levels of immunoglobulins, which the body uses to battle disease, and C-reactive protein, which people produce when they are under stress,” Professor Jelmer Eerkens said.
“It’s heartbreaking to think about children who may have lost their parents and family to disease, were thrown into a new cultural environment they didn’t understand, and how it affected their wellbeing.”
A/Prof Buonasera added, “Without trying to overstate things too much, looking at stresses and immune responses in past populations could provide points of comparison with modern lifestyles that can be especially valuable because you have that depth of time.”
