Mercury Toxicity
By Dr. Paul C. Eck
and
Dr. Larry Wilson

2225 W. Alice Avenue - Phoenix, Arizona 85021 USA 1-602-995-1580
This material is for educational purposes only
The preceding statements have not been evaluated by the
Food and Drug Administration
This information is not intended to diagnose, treat, cure or prevent any
disease.
Copyright © 1989 - The Eck Institute of Applied Nutrition and
Bioenergetics, Ltd.
Introduction
Mercury has been recognized since prehistoric times as a
toxic metal. Lately, interest in mercury poisoning is increasing due to;
| • | several outbreaks of mercury poisoning, |
| • | continued use of mercury in many industrial processes, |
| • | water and airborne contamination and |
| • | new questions regarding its safety in dental amalgams. |
The most threatening mercury compound
is organic methylmercury, although there is risk of contamination from
inorganic mercury compounds as well.
Sources Of Mercury
Mercury can enter the body through the lungs, through food
and water, and by direct physical contact.
Dental Amalgams
Commonly used silver amalgam dental fillings contain about 50
percent mercury. Older dental fillings may contain higher amounts. There is
increasing evidence that mercury is leached from dental amalgam and that
mercury can vaporize from fillings. Fillings which crack can also be a
source of mercury toxicity.
Silver amalgam fillings also generate negative electrical
potentials in the mouth which can detrimentally affect one's health status.
There are alternatives to silver amalgam fillings, including
gold alloys and composite quartz-resin materials.
Large Fish
The concentration of mercury in fish varies directly with the
size of the fish, inasmuch as mercury is more concentrated at each step
upward as one goes up the food chain.
Tuna and swordfish are the most common fish contaminated with
mercury. Most swordfish are kept off the market today for this reason.
Albacore tuna has been found to be safer than the larger species of tuna.
While fish contain selenium, which helps to neutralize the
toxic effects of mercury, we do not recommend eating tuna fish more than
twice a week, due to mercury contamination.
Water Supplies
Mercury in industrial waste is a common water contaminant.
Mercury used in fungicides and slimicides easily finds its way into water
supplies. Sewage sludge is commonly contaminated with mercury.
Seeds Treated With Mercurial Fungicides
Mercury is commonly used as a treatment to prevent fungal
growth on seeds.
Medications
Because of its bacteriostatic properties, mercury is a common
ingredient in antiseptics (Mercurochrome, Merthiolate) and contact lens
solution. Mercury is also found in the thiazide diuretics and in some
hemorrhoid medications.
Congenital Mercury Toxicity
Methylmercury easily crosses the placenta into the growing
fetus. Other mercurial compounds pass with less ease. Mercury compounds can
also be transferred through breast milk to nursing babies. Levels in breast
milk are about five percent of those of blood.
It is believed that fetuses are the group most susceptible to
mercury toxicity. Infants excrete mercury more slowly than adults.
Other
Mercury is widely used in industry and in a variety of
products, e.g., felt, fungicides, algicides used in swimming pools,
adhesives, floor waxes, fabric softeners, slimicides, and in the production
of chlorine.
Detection Of Mercury
Both blood and hair are used to detect mercury toxicity. In
the study by Marsh et al. (1974), hair levels generally correlated directly
with blood levels.
Absolute levels in the hair were about 300 times higher than
in the blood. (Prasad 1976). Hair can also provide a chronological account
of mercury excretion by measuring mercury content of different segments of a
hair sample.
Metabolism Of Mercury Absorption
Mercury is well absorbed through the lungs, the
gastrointestinal tract, and the skin. Methylmercury compounds vaporize
easily and if inhaled in large amounts, can destroy lung tissue.
Organic complexing produces methylmercury compounds, which
are more toxic, especially to the central nervous system. Only seven percent
of ingested inorganic mercury is absorbed, but at least 95% of ingested
methylmercury is absorbed. Zinc, cadmium, and manganese can enhance
absorption of inorganic mercury.
Absorption of mercury through the skin has resulted in fatal
poisoning.
Metabolism
Elemental mercury is oxidized upon ingestion to ionic
mercury, most likely facilitated by catalase. Catalase is an iron-containing
enzyme.
Most ingested mercury is then bound to metallothionein, a
binding protein, or to a metallothionein-like plasma protein, and
transported by the blood plasma.
The various mercury compounds can be converted one to another
by intestinal bacteria and certain liver enzymes.
Tissue Retention
The main target organ for mercury is the kidney, although
deposition in the brain is common. Ingestion of alcohol reduces blood and
brain levels, but increases liver concentrations of mercury.
According to G. Kazantis, Mercury and the Kidney, Trans Soc.
Occup. Med. 20:54, 1970, the kidney retains more mercury than any other
organ in the body. However, in postmortem samples from mercury mine workers
in Yugoslavia, the highest concentration of mercury was found in the thyroid
and pituitary glands, suggesting that retention may be higher in these
organs than in the kidneys.
Excretion
Biliary excretion is the preferred route of excretion of
mercury. Biliary excretion is enhanced by the chelating agent BAL (a
compound developed as an antidote to mercury and arsenic poisoning). Some
mercury is clearly reabsorbed in the intestinal tract; the exact proportion
depends upon the form of mercury.
Mercury is also eliminated in saliva, through the pancreas,
through intestinal wall secretion, and through nails and hair.
In acute mercury poisoning, excretion occurs at a rate of
about one percent per day. However, our research indicates that sequestered
mercury will remain in storage for years.
Cysteine (an amino acid) and selenium delayed or prevented
toxicity when administered simultaneously with mercury in animals. However,
neither caused greater excretion of mercury in feces nor urine.
Metabolic Effects Of Mercury
Energy System
Mercury compounds inhibit ATPase, an enzyme that breaks down
ATP, inhibiting energy release in all cells.
Nervous System
Degeneration of nerve fibers occurs, particularly the
peripheral sensory nerve fibers. Besides sensory nerve damage, motor
conduction speed was reduced in persons with high hair mercury.
The most common sensory effects of mercury toxicity are
paresthesia, or a tingling sensation, pain in limbs, and visual and auditory
disturbances. Motor disturbances are exhibited by changes in gait, weakness,
falling, slurred speech, and tremors. Other symptoms are headaches, rashes
and various emotional disturbances.
Endocrine System
Mercury has been shown to concentrate in the thyroid and
pituitary glands, interfering with their function. Impairment of adrenal
gland activity also occurs.
Metabolic Dysfunctions Associated With
Mercury Toxicity
Adrenal Gland Dysfunction
Impairment of adrenal gland activity due to mercury toxicity
can cause fatigue, low blood sugar, and allergies.
Alopecia (Hair loss)
Mercury toxicity causes impairment of copper metabolism, and
is a common cause hair loss.
Anorexia
Loss of appetite may result from mercury-induced depletion of
zinc in the brain.
Ataxia
Refers to a failure of muscular coordination. Mercury
toxicity results in uncontrolled, slow movements that are a symptom of
nervous system toxicity.
Birth Defects
Studies reveal a higher incidence of cerebral palsy, mental
retardation and neurological deficits including hyper-reflexia and delayed
development.
Fetuses retain more mercury than adults. The placenta
provides no barrier to mercury. Infants may actually act as a sink for this
metal.
Skerfring, Hanson, and Lindsten (1970) found chromosome
damage in humans exposed to mercury through consumption of mercury-poisoned
fish.
Blushing
An interesting effect of mercury toxicity is an exaggerated
tendency to blush in embarrassment.
Depression
Depression may be due to mercury accumulation in the thyroid
and pituitary glands causing a slowing of the metabolic rate.
Dermatitis
Skin problems may be caused by a mercury-induced zinc
depletion.
Discouragement
Discouragement has been repeatedly described in individuals
suffering from mercury toxicity.
Dizziness
Damage to cranial nerve fibers can result in dizziness or
vertigo.
Fatigue
Fatigue may be due to the effects of mercury toxicity on the
adrenal, thyroid and pituitary glands, or interference with cellular energy
production.
Hearing loss
Mercury has an affinity for the acoustic nerve, eventually
resulting in hearing loss.
Hyperactivity
Elevated hair levels of mercury were found in a study of
emotionally disturbed children (Marlowe et al.).
Immune System Dysfunction
Recent research indicates that mercury can have a detrimental
effect upon immune system activity.
Insomnia
Neurological damage due to mercury can cause insomnia in
certain individuals.
Kidney Damage
Mercury can cause sodium retention and other electrolyte
imbalances, which contribute to impaired kidney function.
Loss of Self-Control
Mood swings and emotional instability are frequently
associated with mercury toxicity.
Memory Loss
Damage to nerve fibers can affect all mental functions
including memory.
Migraine Headaches
These may be due to the intimate association between mercury
and copper toxicity. Copper toxicity is known to contribute to the causation
of migraine headaches.
Mood Swings
Hyper-irritability is a common manifestation of mercury
toxicity. In addition, copper toxicity may be involved in the causation of
mood swings.
Nervousness
Behavior changes and emotional difficulties are commonly
ascribed with mercury poisoning.
Numbness & Tingling
Tingling or paresthesia is one of the early signs of mercury
poisoning.
Pain in Limbs
Peripheral nerve damage is an early sign of mercury toxicity
and can cause pain in limbs.
Rashes
Skin rashes and blushing are commonly associated with mercury
poisoning.
Salivation, Excessive
Acute mercury toxicity is a frequent cause of excessive
salivation.
Schizophrenia
Copper toxicity and zinc depletion related to mercury
toxicity may contribute to symptoms of schizophrenia.
Thyroid Dysfunction
Mercury accumulation in the thyroid gland, detrimentally
affects thyroid activity.
Timidity
Mercury toxic individuals may avoid friends and public places
and become despondent.
Tremors
Tremors are usually the first symptom of mercury toxicity.
The tremor usually begins in the face, then progresses to the hands. Later
the tongue is affected, speech becomes slow and slurred and the gait becomes
ataxic. The tremor is an intention tremor, meaning that the more one tries
to control it, the worse it becomes.
Vision Loss - Peripheral Vision
Vision loss occurs due to damage to the optic nerve, not
retinal damage.
Weakness, Muscle
Motor nerves are affected by mercury toxicity. The end result
is muscle weakness.
Effects Of Mercury On Other Minerals
Copper Toxicity Associated with Mercury Toxicity
Individuals who show high serum copper levels, tremor of the hands, ataxia,
and intermittent schizophrenic symptoms with wide mood swings should be
studied as possible victims of mercury poisoning.
Mercury appears to inhibit copper absorption from the
intestine. However, we find that those individuals with mercury toxicity
often later display copper toxicity as well.
Zinc
Zinc depletion of the brain is associated with mercury
toxicity.
Selenium
Mercury protects against selenium toxicity by binding with
selenium.
Effects Of Other Minerals On Mercury
Selenium
Selenium protects against methylmercury intoxication and
other forms of mercury. It appears selenium in tuna fish protects against
mercury toxicity. Mercury-selenium complexes are formed.
Zinc
"To summarize, heavy metal intoxication of the brain can
cause hyperactivity in animals and presumably in some children. This
hyperactivity in rats may be accompanied by a displacement of a sedative
metal, such as zinc, from the brain. We know that zinc will antagonize
mercury toxicity."
"It appears that metallothionein, induced by giving zinc,
complexes with mercury." (Bremmer, 1976)
Detoxification Of Mercury
Detoxification of mercury, as with the other toxic metals, is
accomplished most effectively, in our experience, by a combination of
increasing overall energy levels, enhancing activity of the eliminative
organs and the administration of mercury antagonists and chelating agents.
Enhancing Energy Levels
A tissue mineral analysis is of value in designing
nutritional programs which balance the tissue electrolytes and enhance the
energy pathways. By so doing, increased biochemical energy is made available
to facilitate excretion of mercury from tissue reservoirs.
Enhancing Eliminative Organ Activity
Mercury is excreted primarily through the liver and kidneys.
Herbs and nutrients which enhance liver activity may be helpful, including
sulfur, inositol, choline, methionine, copper and other nutrients.
Kidney activity may be enhanced by the administration of
kidney glandular substance and synergetic factors.
Specific Antagonists and Chelators
Vitamin C
Vitamin C binds heavy metals such as copper, lead, cadmium,
and mercury, and facilitates their excretion by the kidneys.
Selenium
Selenium, if given during mercury exposure, can delay or
prevent mercury toxicity symptoms. However, studies vary with species and
the type of mercury compound used. Selenium tended to decrease kidney
mercury, but increased mercury deposition in the liver and brain. Selenium
administered after mercury exposure probably cannot increase elimination of
mercury.
Glossary
| References | |
| 1. |
Neuro-biology of the Trace Elements, Vol. 2, I. Dreosti and R. Smith, ed., Humana Press, Clifton, NJ, 1983. |
| 2. |
Selenium in Biology and Medicine, J. Spallholz, J. Martin and H. Ganther, ed., AVI Publishing Co., Westport, Ct., 1981. |
| 3. | Toxic Trace Metals in Mammalian Hair and Nails, D. Jenkins, National Institute of Scientific Research, U.S. Dept. of Commerce, EPA, Government Printing Office, 1979. |
| 4. | Toxicology of Trace Elements, R. Goyer and M. Mehlman, ed., Hemisphere Publishing Co., Washington 1977. |
| 5. | Trace Elements in Human Health and Disease, Vol.II, A. Prasad, ed., Academic Press, New York, 1976. |

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