Evidence supporting a link between dental amalgams and chronic illness, fatigue, depression, anxiety, and suicide.[link to article]
Janet K. Kern 1, David A. Geier 1, Geir Bjørklund 2, Paul G. King 3, Kristin G. Homme 4, Boyd E. Haley 5, Lisa K. Sykes 3, Mark R. Geier 1
1 Institute of Chronic Illnesses, Inc., Silver Spring, MD, USA
2 Council for Nutritional and Environmental Medicine, Mo i Rana, Norway
3 CoMeD, Inc., Silver Spring, MD, USA
4 International Academy of Oral Medicine and Toxicology, ChampionsGate, FL, USA
5 University of Kentucky, Lexington, KY, USA
Correspondence to: Janet K. Kern, PhD.
Institute of Chronic Illnesses, Inc.
14 Redgate Ct., Silver Spring, MD 20905, USA.
tel: +1(301)989-0548; fax: +1(301)989-1543; e-mail: firstname.lastname@example.org
The purpose of this review is to examine the evidence for a relationship between mercury (Hg) exposure from dental amalgams and certain idiopathic chronic illnesses – chronic fatigue syndrome (CFS), fibromyalgia (FM), depression, anxiety, and suicide. Dental amalgam is a commonly used dental restorative material that contains approximately 50% elemental mercury (Hg0) by weight and releases Hg0 vapor. Studies have shown that chronic Hg exposure from various sources including dental amalgams is associated with numerous health complaints, including fatigue, anxiety, and depression – and these are among the main symptoms that are associated with CFS and FM. In addition, several studies have shown that the removal of amalgams is associated with improvement in these symptoms. Although the issue of amalgam safety is still under debate, the preponderance of evidence suggests that Hg exposure from dental amalgams may cause or contribute to many chronic conditions. Thus, consideration of Hg toxicity may be central to the effective clinical investigation of many chronic illnesses, particularly those involving fatigue and depression.
Mercury’s toxic effects are broad, variable, and idiosyncratic, and can often be delayed. The effects of chronic, low-dose exposures as from dental amalgam, as well as the modifying effects of genetic susceptibilities, are only beginning to be recognized. Mercury toxicity may be a continuum, with no safe threshold for exposure (World Health Organization 2005). Mercury’s molecular mechanism of toxicity – the binding of thiols and selenols – is unusually broad, resulting in altered structure and function of enzymes, cofactors, receptors, cytokines, ion channels, transport proteins, and transcription factors.
These mechanisms in turn increase oxidative stress, decrease antioxidant defenses, and alter redox balance, which then affect other biochemical processes, often in an interactive manner. Thus, it is understandable why, for example, the Hg-related inhibition of the biosynthesis of neurotransmitters such as serotonin, dopamine, noradrenaline,and GABA, may lead to depression, anxiety and other disorders.
But more research is needed to obtain an integrated understanding of diseases that appear to have multiple causal factors, such as CFS and FM. For example, some of the same biochemical mechanisms found in depression and anxiety might also be important in CFS and FM – with depression and anxiety being primarily brain diseases, while CFS and FM are systemic diseases predominantly affecting other organs and cell types.
This review reports the evidence that supports a link between amalgams and chronic illness, fatigue, depression, anxiety, and suicide; however, it should be mentioned that there are studies that do not support this hypothesis (Dixon 1998; Taut 2013; Bates 2004). For example, Bates (2004) conducted a comprehensive review of the epidemiologic evidence for the safety of amalgams and stated that studies show little evidence of effects on general chronic disease incidence or mortality, including chronic fatigue syndrome. However, Bates also concluded that few relevant epidemiologic studies are available and that better designed studies are needed.
The evidence provided in this review suggests that dental amalgams may be a significant contributing factor in the burden of disease. Furthermore, interactions between Hg and other causes of disease might be more the rule than the exception. However, it may be difficult to assess the relative importance of various causal factors in diseases of multifactorial etiology. This review offers some preliminary mechanistic explanations for several clinical observations in Hg poisoning, especially the often observed neurological and psychiatric symptoms. However, full mechanistic explanations may be elusive for diseases that affect multiple cell types and organ systems in an interactive manner, as appears to be the case for CFS and FM.
This review has presented evidence suggesting a causal relationship between Hg exposure from dental amalgams and CFS, FM, depression, and anxiety. These disorders appear to share common mechanisms, thus are suggestive of a larger disorder – adult dental amalgam (ADA) syndrome – although multiple causes are likely. However, given the evidence, especially the frequent relief of symptoms with amalgam removal, consideration of Hg toxicity may be central to the effective clinical investigation and evaluation of many chronic illnesses, particularly those involving depression and fatigue.
Kern, J. K., et al. “Evidence supporting a link between dental amalgams and chronic illness, fatigue, depression, anxiety, and suicide.” Neuro Endocrinol Lett, 2014, 35(7): 537-552.
Taut, C. “Dental amalgam: is this the end?” Journal of the Irish Dental Association 2013, 59(6): 311–7.
Bates, M. N., et al. “Health effects of dental amalgam exposure: a retrospective cohort study.” Int J Epidemiol, 2004, 33(4): 894-902.
Dixon, S. E. “Amalgams still viable, safe treatment, controversies notwithstanding.” J Indiana Dent Assoc, 1998, 77(1): 37-40.