Teeth analysis could show lifetime exposures to metals, toxins

Analysis of our teeth may show lifetime intake of metals and toxins linked to diseases such as Parkinson's and Alzheimer's, according to researchers, including one of Indian-origin.
"Teeth are of particular interest to us for the measurement of chemical exposure in foetal and childhood development - they provide a chronological record of exposure from their microchemical composition in relation to defined growth lines, much like the rings in a tree trunk," said Manish Arora, of the Mount Sinai Medical Centre.
"Our analysis of iron deposits in teeth as a method for retrospective determination of exposure is just one application - we believe teeth have the potential to help track the impact of pollution on health globally," Arora said.

Arora, along with Dominic Hare, a Chancellor's Research Fellow at the University of Technology Sydney, used the dental biomarker technology to distinguish breast-fed babies from formula fed babies.
This technology can now be applied to study the link between early iron exposure and late-life brain diseases like Parkinson's and Alzheimer's, which are associated with the abnormal processing of iron.
While not all formula fed babies will experience neurodegeneration in adulthood, the combination of increased iron intake during infancy with a predisposition to impaired metal metabolism such as the inability of brain cells to remove excessive metals may damage those cells over time.

"Only now do we have the technology available to use to look back in time at someone's diet as a child, more than 60 years after they stopped wearing diapers," Hare said.

In the case of baby formula, the need to better understand human iron metabolism has become more urgent with the global popularity of formula and fortified cereals.
Adding iron to formula has been an industry standard for decades, in part because about two billion people worldwide - mostly in developing nations - are thought to have chronic anaemia and iron deficiency.
"While it might seem like drawing a long bow linking what happens in childhood to diseases we think of as associated with growing old, the increasing rates of these diseases mean we need to do everything we can to find out what might play a role in how the disease starts," Hare said.

"Knowing this gives us something to target when designing new treatments," Hare said.
Beyond the wide-reaching hypothesis that iron supplementation may increase risk of neurodegeneration, the researchers think a priority in paediatric research should be the rigorous determination of iron supplementation needs of infants according to their individual iron status.