Before yesterday was through, the ADA was in full spin mode over Thursday’s Dr. Oz Show: “Are Your Silver Fillings Making You Sick?” Apparently oblivious to irony, they reiterated their usual claim that there’s “no sound science” supporting mercury amalgam’s well-documented health risks – and then insisted on its safety.
As if saying something often and loudly and forcefully enough could somehow make it true.
It’s like when amalgam’s defenders say that the mercury it contains isn’t the dangerous kind – and is even a little magical:
Mercury is an important component in the fillings because it effectively binds the other metals together, forming a strong bond that contributes to the filling’s durability. It is important to note that there are several kinds of mercury. The mercury found in water that can build up in fish and lead to health problems if you ingest too much is not the same type of mercury used in amalgam. The mercury in amalgam is contained, or sequestered, within the filling.
Of course, even the ADA agrees that mercury vapor is released during chewing or grinding. A 2009 paper in Chemical Research in Toxicology estimated that older fillings may have lost up to 95% of their original mercury content. That mercury doesn’t just disappear, of course. The body’s self-regulating mechanisms clear as much of it as it possibly can. That which isn’t excreted is stored, typically gravitating toward fatty tissues such as the liver and brain.
More, although the mercury in amalgam may start out in elemental form, it doesn’t stay that way. As Dr. Huggins notes in It’s All in Your Head, mercury released from amalgams fillings can become methylated.
Mercury is highly reactive chemically. It likes to combine with biological tissue. In the mouth, mercury has the ability to combine with a carbon-hydrogen compound called a methyl group. When mercury combines with methyl groups it is called methyl mercury.
Methylation actually begins in the mouth , due to the action of oral bacteria, but it can occur elsewhere (also). And “although the amounts found are small,” wrote researchers in the Journal of Nutritional & Environmental Science, “any measurable amount of methyl mercury” only adds to a body’s total toxic burden.
Methylmercury is a bioaccumulative toxin. That’s why mercury in fish – especially fatty fish – is such a concern. When mercury contaminates water, it gets methylated by bacteria. Fish exposed to this methylmercury accumulate it in their bodies. When we eat them, we get a dose of the stuff, too.
Of course, it has other effects, as well – including a somewhat surprising one suggested by a recent study. Methylmercury exposure in young adulthood appears to raise the risk of developing diabetes later in life.
The study, published last month in Diabetes Care, analyzed data from nearly 4000 adults between the ages of 20 and 32. According to lead author Ka He of Indiana University,
Our results are consistent with findings from laboratory studies and provide longitudinal human data, suggesting that people with high mercury exposure in young adulthood may have elevated risk of diabetes later in life.
Why? It may be related, at least partly, to pancreatic beta cell dysfunction. These cells have been shown to play a major role in type 2 diabetes.
The abstract of the Diabetes Care study is available here.
We know that our current diabetes epidemic, like its companion obesity epidemic, has many causes. Further study is needed to know if we need to add yet another cause to that list.
Image by Enzo Carretta, via Wikimedia Commons