Elmer Cranton on Heavy Metal Toxicity





by Elmer Cranton, M.D.

source: www.drcranton.com


Mercury, lead, arsenic, and other metals have been known to be potential toxins for many centuries. When body levels become elevated to a point higher than a safe threshold for tolerance, mercury, lead, and other metals can lead to illnesses and can exacerbate existing diseases. Unfortunately, symptoms of heavy metal toxicity are relatively non-specific and non-diagnostic. There are many other diseases that can easily be misdiagnosed as metal toxicity. A long list of potentially toxic symptoms can cause a person with just about any chronic illness to believe that they are poisoned.

Every metal known to science is widely present in the earth’s crust, in air, in water, in food and in drink—often in very tiny amounts. It is important to understand that all known toxins have a safe low level below which no harm occurs. Below a threshold of safe tolerance, potentially toxic metals will cause no harm.

Laboratory technology has now advanced to the point where extremely low levels can be measured in virtually every person tested. This is increasingly causing fear and a mistaken diagnosis of heavy metal poisoning. It has become fashionable to blame a wide variety of poorly understood diseases on heavy metal toxicity, even when measured levels are much lower than the safe threshold. Some laboratories print test results on report forms that seem to significantly exaggerate toxicity. By using a provocative chelating agent before collecting urine for testing, deceptively elevated levels can be measured in urine. I no longer recommend provocative urine tests and rely on whole blood testing, performed by either LabCorp or Quest Diagnostics laboratories. Those two laboratories are available in just about every city in the USA and they print their results on report forms that use scientifically approved EPA and OSHA reference ranges.

Toxicity does occur and should not be ignored, but when tested properly, using scientifically accepted standards, toxicity not common. It is true that mercury levels are somewhat higher in people with mercury amalgam fillings in their teeth, but recent research shows that levels still remain low enough to be safe.

Please don’t misunderstand me. I dislike all environmental toxins. I enthusiastically support efforts to reduce exposures and to eliminate industrial pollution. It also makes good sense to use nontoxic substances in dental fillings. But it makes no sense to miss a correct medical diagnosis by mistakenly attributing symptoms to low levels of potentially toxic heavy metals. Many patients have come to me over the years after being told elsewhere that mercury or some other metal was causing their symptoms. After being tested properly, using the latest methods and technology, I rarely confirmed heavy metal toxicity. I have tested many hundreds of patients over the years and found that only a small percentage that had significantly high levels of toxic metals.

Two recent studies performed by the University of Washington show that mercury in amalgam dental fillings did not result in high enough mercury levels to cause health problems, even in young children

Bellinger DC, Trachtenberg F, Barregard L, Tavares M, Cernichiari E, Daniel D, McKinlay S.                   Neuropsychological and renal effects of dental amalgam in children: a randomized clinical trial.JAMA. 2006 Apr 19;295(15):1775-83.

DeRouen TA, Martin MD, Leroux BG, Townes BD, Woods JS, Leitao J, Castro-Caldas A, Luis H, Bernardo M, Rosenbaum G, Martins IP.               Neurobehavioral effects of dental amalgam in children: a randomized clinical trial. JAMA. 2006 Apr 19;295(15):1784-92

The human body continuously eliminates mercury and other toxins in urine, feces, hair, sweat, nails and skin. If excessive exposure is avoided, the body will efficiently eliminate most toxins. Mercury, for example, has a half-life in the body of only two to three months with no treatment at all. DMSA by mouth is the preferred treatment for excessively high levels, although avoidance of undesirable exposure is the most important aspect of any treatment plan. DMSA also speeds the elimination of lead, and arsenic, antimony, bismuth, and gold. Lead is preferentially stored in bones and for that reason elimination is slower.

Readers may question what I have written here. I can only refer them to a large body of scientific literature on this subject.

A review article in the American Academy of Pediatrics is somewhat more alarmist with the following conclusions.


Toxic mercury exposure can occur from industrial effluents, environmental contamination, occupational exposure, volcanic gasses, and from emissions by coal fired power plants. Metallic mercury is relatively non toxic and is not significantly absorbed, even when swallowed by mouth. Metallic mercury does evaporate, however, and prolonged breathing of the fumes in a closed space can lead to toxicity.

Lead exposure has greatly diminished in recent years, since the switch to unleaded gasoline, and lead based paints have been taken off the market. Potentially toxic metals have always existed in the earth’s crust and also in every human body at safely tolerated levels. We have good scientific data on which to base the upper safe limits before metal toxicity occurs.

A recent study by the University of Rochester shows that eating ocean fish an average of 12 meals per week did not cause toxicity from mercury, even in pregnant women and small children.

Myers GJ, Davidson PW, Cox C, Shamlaye CF, Palumbo D, Cernichiari E, Sloane-Reves J, Wilding GE, Kost J, Huang LS, Clarkson TW.        Prenatal methylmercury exposure from ocean fish consumption in the Seychelles child development study. Lancet. 2003 May 17;361(9370):1686-92.

By carefully studying large populations of people known to have been poisoned in epidemics mercury exposure, it has been possible to determine the blood, urine and hair levels that resulted in toxic symptoms. This was done at Minamata Bay in Kyushu, Japan. Mercury was there was disposed of into the the bay by a chemical manufacturing company, Chisso, that used mercury as a catalyst in the production of acetylaldehyde. Victims were poisoned by contaminated fish and shellfish from the bay. Another mercury epidemic occured in Iraq, caused by bread made with wheat that had been treated with a methyl mercury fungicide.

A study was done in the Faro Islands on a population of people who accumulated mercury by eating large amounts of whale meat. Whale meat contains a a significant concentration of PCBs, that confused the picture, and whale eating was in binges when whales were caught. A more recent study in the Seychelles Islands involved mercury accumulation from ocean fish that were not contaminated with PCBs and were consumed on a regular basis 12 or more times every week. Data from these studies indicates that the danger is less than previously feared.


How is mercury exposure measured? Scientists can determine a person’s exposure to mercury (especially methyl mercury, the most toxic form) by measuring mercury content in hair. By comparing these levels to the results of very sophisticated batteries of tests, scientists try to determine the lowest level that might be harmful.

At what level does mercury become harmful? Based on scientific results from exhaustive studies of known episodes of poisoning, the World Health Organization has placed the level at which risk begins at 50 ppm of mercury in hair for most people. The WHO then applied a safety factor of 10, estimating that a level of 5 or less is safe for even the most vulnerable populations. More recently the University of Rochester conducted an extensive study in the Seychelles Islands of the most sensitive population (pregnant women and their young children from birth onward) where the average hair mercury level is about 7 ppm, about 10 times the level of the U.S. population. These people ate ocean fish 12 or times or more often every week. Scientists found no harm from mercury at levels up to 15 ppm, nearly twice the average Seychelles level and about 20 times higher than the average U.S. level. Despite those reports, hair analysis laboratories in the U.S. continue to report of toxicity at only 1 ppm.
As you can see immediately above, it is customary for the EPA and for clinical laboratories to apply a safety factor of 10 on report forms. If the lowest known level associated with toxicity is 50 ppm, the WHO sets the recommended range for the general public below 5 ppm. Thus, is it highly unlikely that toxicity is responsible for symptoms unless the measured level is at least 10 time the upper limit on a laboratory report form. For industrial workers who are regularly exposed to mercury on the job, OSHA sets the allowable limits much higher, closer to a proven toxic level, before removing a worker from further exposure CLINICAL INTERVENTIONS

1) Minimize exposure! Prevention is always better than treatment of symptoms. Be aware of your environment, what you eat and drink, what you apply to your skin and chemicals used in the home or at work. If a mercury thermometer or mercury switch breaks, carefully clean up the metallic mercury residue. Waste disposal facilities usually have a way to dispose of toxic substances.

2) With special laboratory tests, experienced health care professionals can evaluate the mercury load within the body. This can be done by measuring whole blood levels. Urine can also be used and but hair is valid only for mercury. This should be performed by a reputable laboratory, on the order of and under the supervision of a licensed health care professional. When urine is measured, no chelator should be given that could increase provoked excretion and cause false positives.

3) DMSA can be used to remove mercury and is taken by mouth. DMSA binds with mercury, arsenic, lead, and probably with antimony, bismuth, and gold, hastening excretion from the body. The usual adult dose for mercury removal is 500 mg DMSA (five 100 milligram capsules) on an empty stomach on first arising in the morning with a glass of water or juice, and no food for another 30 minutes. This dose is taken 3 days per week with at least one day between each dose. Monday, Wednesday and Friday is a convenient schedule. This is continued for 3 months. Then wait another month without DMSA before retesting mercury levels in the body, allowing mercury to equilibrate with blood and body fluids.

4) EDTA has little or no effect on mercury in the body, probably because mercury binds more tightly to other molecules and is present as organic methyl mercury. Mercury removal is the one problem for which oral treatment is the best choice, using DMSA by mouth.

5)DMPS is potentially too toxic to use and no longer has no place in the practice of medicine.

6) Nutritional supplements, that contain magnesium and selenium, along with a wide variety of other essential micronutrients, can act as partial antidotes to mercury and other metallic toxins.

Click here to receive more information about mercury toxicity

Click here for more information about mercury and heavy metal toxicity


Mercury Fillings: Are they Really Safe?

Clinical Toxicology of Mercury

Testing for Toxic Elements.

Treatment of Mercury and Lead Poisonings with DMSA and not DMPS.

Avoid Misleading Provocative Testing

How to Interpret Toxic Metal Blood and Urine Tests.

Mercury Testing is Often Performed Incorrectly, Causing False High Results.

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