Last week, the IAOMT sent its member dentists and physicians an information packet on the recent news coverage of studies showing links between mercury exposure and Alzheimer’s disease. It included a helpful comment on the studies by Jim Dickinson of FDAWebview, with a note that Jim had given permission to share the article – which we think is definitely worth sharing:
Mercury Hazard from Amalgam Greater than Thought: 2 Studies
Barely a month before it has elected to officially hear critics of its 2009 final rule finding dental amalgam safe and effective, the agency is confronted by two new studies condemning the health damage caused by amalgam’s principal ingredient, mercury. One, prepared for a 12/15-16 special FDA advisory committee meeting on dental amalgam risks and delivered last week, examines U.S. public exposure to mercury and suggests that amalgam fillings expose 122.3 million Americans to quantities of mercury in excess of the safe dose level established by the California Environmental Protection Agency in 2008. This reference exposure level is accepted by other government agencies for public protection. The other study, published in the 11/15 issue of the Journal of Alzheimer’s Disease, directly links mercury in amalgam causatively to that disease.
Both studies effectively contradict an assertion made at a 7/28/09 press conference on the new amalgam rule by CDRH Dental Device Division acting director Susan Runner: “The best available scientific evidence supports the conclusion that patients with dental amalgam fillings are not at risk for mercury-associated adverse health effects.”
The first study is also critical of FDA’s failure to consider the additive effect of non-dental sources of mercury and the compounding effects of similar neurotoxins such as lead and methyl mercury. “Neurological effects, particularly in the nervous system of the developing fetus/neonate/child, represent the most sensitive endpoint for exposures to” these neurotoxic substances, says the study report, commissioned by the International Academy of Oral Medicine and Toxicology (IAOMT), which is among petitioners presenting at next month’s FDA meeting.
Noting recent literature on the combined, interactive and additive neurological effects of the three heavy metals in humans, the 11/11 study by Ottawa, Canada-based SNC-Lavalin’s G. Mark Richardson et al., says potential neurological effects of lead and mercury on the developing brain of the fetus are likely to accumulate via the placenta and breast milk. The study report’s Discussion/Conclusions section estimates that more than 121 million Americans have an exposure level from the combined three heavy metals that exceeds the 2003-04 National Health and Nutrition Examination Survey safety standard. It reached this conclusion, it says, based on criteria set out in guidance issued by both the U.S. Agency for Toxic Substance and Disease Registry and the Environmental Protection Agency.
“All of these substances,” it says, “share the following characteristics:
- All are absorbed in large proportion into systemic circulation;
- All cross the blood-brain and placental barriers;
- All cause neurological toxicity;
- Exposure to all of these substances currently exceed individual reference exposure levels for many in the U.S. population.”
The report also notes that, although not part of the study, high fructose corn syrups have recently been found to contain high levels of inorganic mercury, with average daily intakes in the U.S. at 50 grams per person “due to its widespread use in numerous commercial prepared foods and sweetened beverages.”
In the second study, Northeastern University neuropharmacology professor Richard Deth co-authored with Germany’s Joachim Mutter a meta-analysis of 106 case-control or comparative cohort studies to associate mercury as a causative factor in that disease. Noting that the main source of mercury in the human body is dental amalgam, the authors say the mercury “evaporates at a slow rate, but is released at a higher rate, when the fillings are put in place or removed. From this source, and other, less common ones, 1.2 to 27.0 ng of Hgo [elemental or metallic mercury] are taken up per day, and 1.0 to 22.0 ng of Hgo are retained. Other variable factors of mercury release include the number, age, and size of the fillings, the presence of dental alloys, individual chewing habits and drinking hot liquids, as well as bruxism.”
A news release issued by the authors quoted Viadrina European Universityand Samueli Institute Fellow Harald Walach as saying: “The situation is similar to the early 1970’s regarding smoking: enough experimental evidence existed, but human studies were inconclusive at the time and were under attack by groups with a vested interest. To wait until irrefutable evidence has accumulated is not the best option in view of what we already know about the toxicity of mercury. The removal of inorganic mercury from ecological cycles might prove to be the easiest and most effective public health measure to contribute to the prevention of Alzheimer’s disease.”
Petitioner IAOMT issued a news release hailing the Mutter-Deth study and urging NIH to fund “realistic research” on the mercury-Alzheimer’s link and quoted California first lady Maria Shriver as expressing concern that Alzheimer’s Disease “will bankrupt every family in this country.”
You can read the full Journal of Alzheimer’s Disease study here (PDF).