First Do No Harm:
The Physiological Consequences of Mercury in the Body
Nita Bishop, N.D.
In 1978 a classic paper written by Theron Randolph, M.D. elucidated what may have been the precursor to our current understanding of environmental toxins and how they affect the body over a long period of time. Randolph refers to the over-all dynamic interplay between specific environmental exposures and the chronic and acute responses of reacting individuals. He comments on stages that an organism goes through in order to adjust to gradually changing circumstances which he calls ¡°adaptation,¡± and provides us with a working blueprint of what may be occurring in the body as a result of mercury toxicity.
The human body functions as an intricate grid work of biochemical reactions which power metabolic functions leading to overall physiological functions. Negative effects on health often only become apparent after a number of years. Rather than a sudden onset, disease is caused by a certain number of cumulative biochemical processes that become aberrant over years, causing a slow progression from health to disease. By thoroughly studying this process, one may be able to identify a wide range of interrelated physical and mental illnesses. Mercury intoxication may reside somewhere in this gray area. Randolph states that environmental exposures have been blurred by the general tendency to treat most illnesses symptomatically by means of drugs. Unfortunately, these gray areas may often lead to misdiagnosis resulting in patients being treated ineffectively and often incorrectly. These symptoms may in some part be the culmination of many years of malfunctioning biochemical processes leading first to immune dysfunction then progressing to astrocyte destruction within the brain, neuronal swelling, inhibition of dopamine uptake, and alterations in serotonin and norepinephrine metabolism, all of which can have a negative affect on mood.
Neither the recognition nor the treatment of heavy metal toxicity is an isolated event. A patient may have periods of weeks to years where they are highly functional and productive, interspersed with periods of being nonproductive and having a difficult time completing tasks. These patients may be diagnosed with psychological problems including: borderline personality disorders, anxiety, schizophrenia spectrum disorders, attention deficit hyperactivity disorder, learning disabilities, depression, obsessive-compulsive disorder, manic depressive disorder, and panic attacks. All of these conditions may in some way be correlated to mercury intoxication. Additionally, some studies have investigated possible relationships of mercury levels to emotional disturbances in children. Subtoxic metal levels previously thought to be harmless are now being associated with hyperactivity, impulsiveness and decreased attention span.
In the Handbook of Toxicology of Metals, it is noted that ¡°¡¦at present, there is no suitable biological index of the mercury concentration in critical organs such as the brain¡¦¡± Mercury is ubiquitous in our environment. Today the average person's body contains about 10-15 mg of mercury. Mercury is employed by medical and dental practitioners, found in drugs, used by agriculture in fungicides and pesticides and by the cosmetics industry as an antibacterial. Mercury in industrial waste has also polluted our waters and contaminated our fresh and salt water plants and fish.
Methylmercury and elemental mercury are the two forms most likely to be involved in human exposures in our environment. Elemental mercury is converted by bacteria to the more toxic methylmercury. Ingested methylmercury is absorbed through the GI tract while inhaled mercury vapor is retained by the pulmonary system. Skin absorption of mercury may also occur.
1. Methylmercury (recent exposure to organic mercury within last 90 days): This form is from industrial pollution and gold mining. It accumulates mainly in the aquatic food chain. Greater than 95% is found in food, particularly fish (higher levels in shark, swordfish, tuna (canned, fresh/frozen), salmon, halibut. It tends to concentrate in the brain where it acts as a potent neurotoxin and teratogen.
Testing for Acute Exposure — utilizing hair, urine, blood and feces
2. Elemental (all other chronic exposures): Silver amalgam fillings are 50% Hg content. While the American Dental Association says it is stable, its release is increased by chewing food, chewing gum, tooth grinding, drilling or polishing teeth as well as consuming hot drinks.
Testing for Chronic Exposure — utilizing hair, fractioned urine porphyrin
Biochemical effects: Mercury binds covalently with sulfhydryl groups, especially those contained in hemoglobin, glutathione (GSH), and cysteine. It reduces glutathione synthase/reductase, selenium and vitamin E, and forms insoluble complexes with selenium, therefore decreasing selenium levels. It promotes formation of prooxidants such as hydrogen peroxide, lipid peroxides and hydroxyl radicals. Most importantly, it affects the Phase II detoxification pathway in the liver. After entry into the body, the liver is the main organ that neutralizes toxic compounds where they undergo metabolic changes whereby lipid soluble compounds are converted into polar, water-soluble products for purposes of excretion from the body. Phase I detoxification is where foreign compounds are converted to more potent or less potent compounds, readying them for the next phase of processing, which is Phase II detoxification. In Phase II detoxification metabolites produced in Phase I are combined with endogenous molecules and become less toxic and harmful, more water-soluble and therefore readily available for excretion.
What Mercury poisoning does to your body
Mercury has a number of mechanisms leading to toxicity in biolog |