Teeth reveal lifetime exposures to metals, toxins

http://www.eurekalert.org/pub_releases/2015-07/tmsh-trl072215.php

Public Release: 22-Jul-2015
The Mount Sinai Hospital / Mount Sinai School of Medicine

Is it possible that too much iron in infant formula may potentially increase risk for neurodegenerative diseases like Parkinson's in adulthood -- and are teeth the window into the past that can help us tell? This and related theories were described in a "Perspectives" article authored by researchers from the Icahn School of Medicine at Mount Sinai and the University of Technology Sydney and Florey Institute of Neuroscience and Mental Health in Australia, and published online recently in Nature Reviews Neurology.

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Dr. Arora, along with Dominic Hare, PhD, used the dental biomarker technology to distinguish breast-fed babies from formula fed babies. Now this technology can 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.

Dr. Hare, a Chancellor's Research Fellow in the Elemental Bio-imaging Facility at the University of Technology Sydney, says "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. State-of-the-art imaging technology is a chemical time machine that can tell us about decades-old chemical exposures that are equivalent to a drop of ink in a swimming pool."

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 anemia and iron deficiency. Evidence, however, that children in the United States or Europe, for instance, get too little iron is insufficient, according to the authors, and the reported developmental and nutritional benefits of iron are modest. The European Society for Paediatric Gastroenterology, Hepatology, and Nutrition have since stated that there's no evidence that babies of normal birthweight need iron supplementation, yet in the U.S. it's still commonplace. Dr. Hare continues: "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. Knowing this gives us something to target when designing new treatments."

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