Dental x-rays reveal mummies' diets

Analysis of tooth cementum gives insight into ancient lives.

An analysis method for looking at trace metals in human teeth has been demonstrated by scientists from Canada, Germany and Peru.

Teeth are thought to provide a record of an individual’s exposure to metals from their diet and the environment, and while analysis of the enamel has been focused on, little attention has so far been paid to the cementum. Cementum is a tissue covering the roots of the teeth and is believed to be laid down in annual rings. This means that it has the potential to show an individual’s long-term exposure to metals.

Ronald Martin and Steven Naftel at the University of Western Ontario, London, Canada, together with Andrea Feilen from Ludwig Maximilians University, Munich, Germany, and Alfredo Narvaez at the Instituto Nacional de Cultura, Peru, have used synchrotron micro-x-ray fluorescence (XRF) to analyse the cementum rings of teeth from two mummies from Tucume, Peru, dating from the early 1500s. The results, which showed that metals such as zinc are concentrated in the cementum rings, have allowed the researchers to speculate about the these ancient people’s probable diet.

Synchrotron micro-XRF provides an ideal tool to examine the metal enrichment in cementum rings and its possible origin, for example from diet or disease. The technique’s sensitivity combined with the nature of cementum deposition also means that signals from metals laid down during the mummy’s life can be separated from those that have accumulated in the teeth post-mortem. Continued research will allow an unprecedented insight into the historic availability of metals in the human diet.

Rowena Milan