Dr Chris Shade on Mercury Toxicity and the mercury challenge test
In this audio, Chris Kresser talks with Dr. Chris Shade, an expert in the environmental and analytical chemistry of mercury, about how we get exposed to mercury, the affect it can have on our bodies, what determines sensitivity to mercury, and the right (and wrong) way to test for mercury toxicity.
While they do get a bit over the top, technically, for many listeners I urge you to listen in. In particular I want you to take note of Dr Shade's views on the mercury challenge test. This test is still popular with many doctors and naturopaths. It is true that close to 100% of those people who undergo the mercury challenge test will prove to be positive for mercury toxicity. As Dr Shade and Chris Kresser agree; a test that is positive with just about everyone must be taken with great skepticism. Gosh - many people have then gone and spent thousands of dollars on removing amalgam fillings and chemical chelation! In some cases this was unnecessary. A more gentle and less costly approach usually suffices.
"Urine mobilization test," "challenge test," and "provoked urine test" are all terms used to describe the administration of a chelating agent to a person prior to collection of their urine to test for metals. There is no standard, validated challenge test. Despite recommendations by professional and government organizations against the use of provoked urine testing, the tests are still commonly used and recommended by some practitioners. Challenge testing utilizes a variety of chelating agents, including dimercaptosuccinic acid (DMSA), dimercaptopropanesulfonate (DMPS), and ethylenediaminetetraacetic acid (EDTA). The agents are given by a variety of routes of administration, doses used are inconsistent, and urine collection procedures vary. Additional problems with challenge tests include comparison of results to inappropriate reference ranges and creatinine correction of urine obtained within hours of chelator administration. Human volunteer studies demonstrate that mercury is detected in the urine of most people even in the absence of known exposure or chelator administration, and that urinary mercury excretion rises after administration of a chelator, regardless of exposure history and in an unpredictable fashion. Studies also demonstrate that challenge testing fails to reveal a "body burden" of mercury due to remote exposure. Chelating agents have been associated with adverse reactions. Current evidence does not support the use of DMPS, DMSA, or other chelation challenge tests for the diagnosis of metal toxicity. Since there are no established reference ranges for provoked urine samples in healthy subjects, no reliable evidence to support a diagnostic value for the tests, and potential harm, these tests should not be utilized.
[PubMed - indexed for MEDLINE]
A more accurate test that I am very familiar with, and have thousands of comparative test results as guidance, is the ICL Hair Tissue Mineral Analysis. This test is very accurate, using the same technology as used by the Mars River, Curiosity, to measure mars soil and rock minerals. If mistakes are made it is not the test that's the problem; but the person interpreting it that is going wrong.
If you have been told you have mercury in your system (Hey - we all do - but it varies how much!), my recommendation is the ICL Hair tissue minerals analysis, followed by gentle chelation, if warranted, using special nutrients such as Algotene, while avoiding any form of chemical chelation which may do more harm that good.
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