Everyday numerous hazardous heavy metals are inhaled and absorbed. The major concern with heavy metals is their ability to accumulate in the environment and cause heavy metal poisoning. Acute heavy metal toxicity is rare; however, chronic low-grade toxicity may be more damaging long-term, contributing to chronic illness.
According to the fourth edition of Mosby’s Medical, Nursing & Allied Health Dictionary (Mosby, 1994) a heavy metal is “a metallic element with specific gravity five or more times that of water.”
Heavy metals include:
- Antimony
- Arsenic
- Cadmium
- Cerium
- Chromium
- Cobalt
- Copper
- Gallium
- Gold
- Iron
- Lead
- Manganese
- Mercury
- Nickel
- Platinum
- Silver
- Tellurium
- Thallium
- Tin
- Uranium
- Vanadium
- Zinc.
Nutritional health requires heavy metals such as chromium, iron, manganese, and zinc. They are not toxic unless taken in large amounts. Other heavy metals such as mercury, arsenic, and lead are toxic heavy metals, and even at low levels can cause heavy metal poisoning.
Aluminium, although having a toxicity risk to humans, is not a heavy metal.
Toxicity of Heavy Metals
Heavy metals and other toxins may alter, remove, or impair the production of specific molecules needed in the body. They may alter the structure of various cell structures such as the mitochondria or a cell nucleus. Additionally, heavy metals may create disturbances in the cell-to-cell communication occurring between inflammatory mediators, nerve cells, or hormones.
Toxic heavy metals target sites such as membrane or structural proteins, enzymes, or DNA molecules. Once at the target site, they can displace an important mineral from its binding site and “pretend” to be this mineral. This is called ‘”molecular mimicry”.
However, the heavy metal can not perform the mineral’s function and acts as a barrier, stopping any activity at the binding site. This affects the function of the cell.
Symptoms of Heavy Metal Poisoning
Heavy metal toxicity can be hard to diagnose due to the wide variety of ambiguous symptoms. Symptoms may include the following:
- Headache
- Fatigue
- Muscle pains
- Indigestion
- Tremors
- Constipation
- Anaemia
- Pallor
- Dizziness
- Poor concentration.
Heavy Metal Testing
Blood, hair and urine tests are the most common forms for heavy metal tetsing.
Hair testing will provide more reliable information on mercury from seafood sources (methylmercury) than for mercury from dental amalgam fillings (elemental mercury). However, hair testing is an inexpensive and non invasive test to start with when looking at heavy metal toxicity. Hair testing is particularly good for children.
A urine pre- and post-provocative test verifies methylmercury toxicity and tests for elemental mercury. This involves providing a urine sample then ingesting a chelating (metal binding) agent, which removes the mercury from the tissues, and following up with another urine test. This measures the level of mercury before and after chelation.
Summary
Heavy metal toxicity may be a “silent” threat. As people age they accumulate more heavy metals but are also more susceptible to their toxic effects. Heavy metal poisoning can cause a wide range of subtle symptoms, but the damage is profound. Promotion of heavy metal testing will benefit human health in the long term.
References:
Bock, S. (1999). Diagnosis and treatment of heavy metal toxicity. International Journal of Integrative Medicine, 1(6), 7-12.
Bralley, J. A., & Lord, R. S. (2001). Laboratory Evaluations in Molecular Medicine. Norcross GA: The Institute for Advances in Molecular Medicine.
Crinnion, W. J. (2000). Environmental medicine, part three: long-term effects of chronic low-dose mercury exposure. Altern Med Rev, 5(3), 209-223.
Pizzorno, J. E., & Murray, M. T. (Eds.). (2005). Textbook of Natural Medicine, 3rd ed: Churchill Livingstone.
The National Academy of Sciences (Ed.). (2000). Toxicological Effects of Methylmercury. USA: The National Academy of Sciences.
Melissa Peterson - Melissa Peterson is a naturopath specializing in nutrition education. Melissa has been writing and editing technical and patient-friendly ...
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