Mercury’s toxic properties have been apparent for centuries. Nonetheless, from the time of the first Emperor of China on, doctors have been fascinated with the metal’s purported curative properties. In the 19th and early 20th centuries, health practitioners blithely used mercury as a medical treatment for everything from syphilis to teething discomfort to dysentery.
As early as the 1820s, some healers began to object to the practice of “giving poison as medicine,” but, in many branches of medicine, physicians remained enthusiastic. In the late 1890s, for example, the prestigious scientific journal The Lancetpublished case studies broadcasting doctors’ seemingly successful use of mercury for the treatment of heart disease. Referring to a mercurous chloride compound called calomel (also called the “blue pill”), Dr. Arthur Foxwell in Birmingham praised, in September 1895, mercury’s “unique” virtues as a cardiac tonic capable of “freeing” a sluggish heart of “half its labour.”
Although many researchers have focused heavily on mercury’s neurotoxicity in children, others acknowledge that, in adults, the cardiovascular system may be exquisitely vulnerable to mercury’s toxic effects.
Over a century later, the medical perspective on mercury and heart disease has come to look quite different. Although many researchers have focused heavily on mercury’s neurotoxicity in children, others acknowledge that, in adults, the cardiovascular system may be exquisitely vulnerable to mercury’s toxic effects. A simple search using the terms “mercury” and “heart disease” in PubMed (the National Institutes of Health database) pulls up ample documentation detailing a higher prevalence of cardiovascular disease in individuals who have higher blood levels of mercury. Mercury damages the cardiovascular system even at low concentrations of exposure.
Effects of Mercury on the Heart
Researchers who acknowledge that mercury exposure increases cardiovascular risk often profess ignorance about the underlying cellular mechanisms of harm. However, a trio of relatively recent articles makes it apparent that scientists actually know quite a bit about how mercury exerts its cardiotoxic effects. Two of the reports, published in 2011 in the Journal of Clinical Hypertension and in 2014 in the Journal of Cardiovascular Diseases & Diagnosis, are authored by Vanderbilt University professor and hypertension expert Mark Houston, who has published extensively on hypertension and heart disease since the 1980s. Dr. Houston began turning his attention to the ramifications of mercury exposure for heart disease a decade ago. A newer study, a review by Italian researcher Giuseppe Genchi and colleagues that appeared in the International Journal of Environmental Research and Public Health in 2017, also reviews mercury’s overall toxicity and specific cardiovascular effects.
…the clinical consequences of these and other pathophysiologic mechanisms explain the wide variety of cardiovascular diseases caused by mercury.”
It should not be surprising that many of the biological mechanisms that explain mercury’s deleterious impacts on the brain (recently summarized here by World Mercury Project) likewise create problems for the heart. Dr. Houston’s two articles list 22 different vascular biological effects of mercury that he further distills into the eight categories shown in the table below. According to Houston, “the clinical consequences of these and other pathophysiologic mechanisms explain the wide variety of cardiovascular diseases caused by mercury.” These conditions include: hypertension, diastolic dysfunction, generalized atherosclerosis, coronary heart disease, myocardial infarction, cardiac arrhythmias, reduced heart rate variability, sudden cardiac death, cerebrovascular accidents, carotid artery obstruction and left ventricular hypertrophy.