by Mark D. Filidei, DO
San Francisco Preventative Medical Group
345 West Portal Avenue
San Francisco, CA 94127
http://www.sfpmg.com
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The term “heavy metals” refers to elements of specific weight
characteristics. Toxic heavy metals are, unfortunately, present in our
air, water, soil, and food supply as a byproduct of our industrialized
society. In fact, contamination is so pervasive in our environment that
it is no longer a question of whether one has been exposed to toxins, but
rather the level of exposure. People who have acute toxicity from heavy
metals – such as lead, mercury, arsenic, and cadmium – may exhibit
obvious and classical symptoms of poisoning. But toxicity from chronic
low-level exposure is much more insidious in its presentation. Chronic
low-level exposure can lead to a wide array of problems, ranging from
neuropsychiatric disturbances such as aggressive behavior, memory loss,
depression, irritability, and learning deficits, to physical
manifestations such as liver and kidney dysfunction, fatigue, infertility,
gout, hypertension, headache, and candida (yeast) infections.
Even though efforts are under way to curb the output of toxins and heavy
metals into the environment, the problem is far from being resolved.
Today, even in the United States, thousands of tons of toxic industrial
wastes, including heavy metals, are dumped into the environment every
year. We are left with a legacy of years of industrial pollution and toxic
substance use that haunts us to this day. Perhaps the two most widespread
and significant heavy metal toxins are mercury and lead.
Lead
It is estimated that about 64 million homes in the United States still
contain lead paint and that 5 to 15 million of these have been identified
as "very hazardous" by the U.S. Department of Housing and Urban
Development. According to the EPA, an estimated 1.7 million children are
currently affected by lead toxicity in United States, and almost 900,000
of all children affected are under the age of six. This statistic is very
important because the symptoms of lead poisoning in children are
strikingly similar to several psychiatric "diseases" that are on the rise
in the U.S. Children with high lead levels can exhibit lower IQ scores,
learning disabilities, hyperactivity, aggressive or disruptive behavior,
and difficulty maintaining attention. A child exhibiting this type of
behavior today would likely be sent to a doctor's office, diagnosed with
attention deficit disorder, and promptly started on Ritalin or other
psychoactive drugs.
Children with high lead levels are much more likely to drop out of school,
have reading disabilities, and exhibit criminal behavior. Herbert
Needleman, M.D., a professor of psychiatry and pediatrics at the
University of Pittsburgh, conducted a study of nearly 2,000 children in
Boston. He found that girls with elevated levels of lead were more likely
to be dependent, to be poor at concentration, and to "display an
inflexible and inappropriate approach to tasks," while boys were more
likely to have difficulty with simple directions and sequences of
directions. Dr. Needleman concluded: "…Our findings would appear to add
to the weight of evidence that even a lower level of exposure to lead, or
its correlates, place children at increased risk of difficulties in
school."
It is important to note that childhood exposure to lead can result in
adverse effects well into adulthood. A study by Stokes, et al, showed that
a group of 281 young adults who had been exposed to lead as children
showed significant adverse neurobehavioral effects 20 years after
environmental exposure. While lead has been eliminated from the nation's
gasoline supply, the major source of contamination is lead-based paint,
which was composed of up to 50% lead. Flakes and microscopic dust from the
paint continue to contaminant homes for many years, and can be released in
larger amounts during renovations. Additional sources of lead include
water pipes, pesticides, factory emissions, cosmetics, and some folk
remedies.
In addition to being a cellular toxin, lead competes with calcium in the
body, which can cause various malfunctions in calcium metabolism including
a decrease in neurotransmitter (chemicals that relay messages along nerve
cells) release and blockade of calcium channels. The central nervous
system appears to be affected to the greatest degree by lead toxicity, and
this can explain the many neuropsychiatric symptoms associated with
exposure to this heavy metal.
Why are some people more susceptible to heavy metal toxicity than others?
One must always remember that each individual has a unique physiology, and
may have an inherently strong or weak detoxification system to handle
heavy metal exposure. In addition, poor nutrition, such as iron or
calcium deficiency, has been shown to exacerbate the symptoms of lead
exposure.
Lead can be absorbed through the gastrointestinal tract and also inhaled
as small particles. Chronic exposure to lead can result in significant
accumulation in the brain, soft tissue, and bones. Lead that has
accumulated in the skeleton can remain there for many years, releasing
lead slowly back into the bloodstream over an extended period of time.
Neuropsychiatric symptoms of chronic lead exposure include:
Headaches
Poor memory
Inability to concentrate
Attention deficit
Aberrant behavior
Irritability
Temper Tantrums
Fearfulness
Insomnia
Lowered IQ
Difficulty with the reading, writing, language, visual and motor skills
Mercury
Mercury is considered by many to be even more toxic than lead. Although
mercury is poorly absorbed from the gastrointestinal tract, mercury vapor
is easily taken in through the lungs and readily passes into the brain.
Once in the body, mercury also concentrates in the nerves, liver, and
especially the kidneys. Mercury is a potent cellular toxin and is known
to decrease neurotransmitter production, disrupt important processes
within the nerve cells, and decrease important hormones such as thyroid
and testosterone.
"Silver" amalgam fillings are the major source of inorganic (does not
contain carbon) mercury exposure in humans, while seafood and fish
constitute our largest exposure to organic mercury compounds. Amalgam
fillings actually contain approximately 50% metallic mercury, and they
continuously release mercury vapor during chewing, brushing, or when
drinking hot beverages. Studies have shown that exhaled air of subjects
with amalgam filling contains a significantly higher level of mercury than
subjects without amalgams, and there appears to be a direct correlation to
the number of amalgam fillings and the level of mercury found in both
blood and urine.
Although the presence of higher levels of mercury in people with amalgam
fillings is not in dispute, there continues to be an intense debate
regarding the health effects of this finding. While groups such as the
FDA and the American Dental Association steadfastly maintain that amalgam
fillings are safe, a growing number of physicians and researchers are
convinced that mercury from amalgam fillings poses a significant health
hazard.
In addition to amalgam fillings, common sources of mercury include
pesticides, laxatives, batteries, paper and pulp products manufacturing,
drinking water, and paint products.
Neuropsychiatric symptoms associated with mercury toxicity include:
Insomnia
Nervousness
Hallucinations
Memory loss
Headache
Dizziness
Anxiety
Irritability
Drowsiness
Emotional instability
Depression
Poor cognitive function
Diagnosis
The diagnosis of heavy metal toxicity must take into account the exposure
history, clinical signs and symptoms, and laboratory tests. While the CDC
(Center for Disease Control) has steadily dropped the "allowable level" of
lead in the blood over the last fifteen years, there remains a problem
with using blood levels in the first place. Blood levels may not
accurately reflect the total body burden of toxic metals. High blood
levels are usually only found in acute toxic metal exposure, or in people
exposed to high levels of toxins over a long period of time. In chronic
low level exposure, however, the blood levels may actually be low due to
redistribution of the toxins throughout the body, while bone and other
tissue levels remain high.
Hair analysis is another method of determining toxin exposure that is
popular with many clinicians. Hair can be a good indicator of exposure
because it grows slowly and incorporates toxic metals into its structure
over a long period of time, and therefore may be a better measure of
actual tissue levels. There are arguments over the accuracy of hair
analysis due to the possibility of contamination from hair dyes, shampoo,
and other factors. Nevertheless, hair analysis can be a valuable
screening tool if the proper questions are asked and the proper steps are
taken prior to its use.
A more accurate method for evaluating toxic metal burden is to do a urine
challenge test with a “chelating” agent. Chelating agents bind to heavy
metals throughout the body, and then are excreted in the urine, taking the
heavy metals with them. In the urine challenge test, a chelating agent is
administered and then urine is collected and analyzed to determine the
amount and type of toxic metals that are excreted.
Treatment
The good news is that effective treatments are available for heavy metal
toxicity. DMSA is an FDA-approved chelating agent that is particularly
useful in cases of mercury exposure (it is also approved for lead toxicity
in children), while EDTA is particularly useful for lead toxicity. It
should be noted that both of these agents remove other toxic metals in
addition to lead and mercury. There are many different protocols used for
heavy metal detoxification, as well as other chelating agents, but that is
beyond the scope of this article. For more information on detoxification
protocols and testing, contact an alternative medicine physician familiar
with these procedures.
Summary
Toxic heavy metals are found in the air we breathe, the food we eat, and
the houses we live in. Toxic metal exposure can result in a wide array of
common mental health disorders that can mimic many psychiatric “diseases”
and thus lead to psychoactive prescription drug use or other unnecessary
treatments. Unfortunately, the majority of clinicians dealing with
patients who have mental health issues are unlikely to suspect heavy metal
toxicity as a cause of their patient’s problems due to a general lack of
knowledge of this subject in the medical community. Unique biochemical,
genetic, and nutritional factors can make certain people more susceptible
to the effects of toxic heavy metals, thus each case must be handled on an
individual basis. Fortunately, the number of practitioners trained in
“functional” or “orthomolecular” medicine is on the rise, and these
practitioners are very familiar with the diagnosis and treatment of
problems associated with heavy metal toxicity.
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