What’s an acceptable level of mercury in your body? I tell my patients “zero,” or an undetectable amount, is the number you want to see on your heavy metal laboratory test. But what’s the best way to find out if you are toxic or sensitive to sub-toxic levels?
How Much is Too Much?
My patients are confused about heavy metals. They focus on mercury, but don’t know what it is or what it does in the body. It’s almost always found in some amount in a blood test, but I rarely find high levels. Most often, it’s arsenic that leads the toxic pack.
Though it’s well known that mercury is poisonous, patients forget to look at arsenic, cadmium, lead, and aluminum—all heavy metals that can cause sickness. Most people believe that hair testing is the best method. Clinically speaking, however, urine and blood produce more consistent results. Regardless of which test is used, no one knows what’s an acceptable level of mercury, or when even a low level may be too high.
The LabCorp Mercury Blood Test states that with environmental exposure, acceptable levels are 0.0-14.9 µg/L. People consuming large quantities of seafood, however, may have values as high as 200.0 µg/L. According to this test, over 15 is too much and 200 is extremely high. That’s a wide range. But how about people with levels at 12? Is this amount too high for some?
Urine testing is best for those with recent industrial exposure, which allows for a level of less than 20.0 µg/L. Some forms of mercury are not sufficiently metabolized in the body, so stool testing is better.
What about people who are “sensitive,” like those with gluten intolerance? Enter the new science of environetics or envirogenetics, a hybrid word combining the concept of toxic exposure and genetic risk.
Beyond Standard Testing
The standard blood tests, urine, hair, and stool analyses provide different ways to check for toxic metals in the body. I don’t rely on one single test for my patients, though, as none of these tests have a high specificity, so accuracy is poor when detecting lower levels.
Environmental health can get very personal. Your genes play an important role in health and disease, and whether you are at a higher risk for getting sick from toxic exposure. We are not far away from tests that evaluate your personal risk to everyday levels of mercury, like from eating fish.
The genetics we are born with impact the way our body copes with the effects of the environment, including exposure to mercury. New tests will give us a better view of environment and gene interactions, especially for those with a heightened risk for the ill effects from mercury.
Primer On Mercury Toxicity
The science behind mercury toxicity is complex. In fact, there are three different forms of mercury that cause health problems:
- Elemental mercury, also known as liquid mercury or quick silver.
- Inorganic mercury salts.
- Organic mercury.
Elemental mercury is found in:
- Glass thermometers
- Electrical switches
- Fluorescent light bulbs
Inorganic mercury is found in:
- Chemistry labs
- Some household and commercial disinfectants
- Folk medicines like traditional Chinese Patent Medicines that use the mineral red cinnabar
Organic mercury is found in:
- Older germ-killers (antiseptics) such as mercurochrome (this substance is banned by the FDA but is still found in some third-world countries)
- Thimerosal in vaccines
- Fumes from burning coal
- Fish that have eaten a form of organic mercury called methylmercury
Acute and chronic mercury poisoning affects the kidneys, central nervous system, and the gastrointestinal tract. The three telltale symptoms of acute mercury poisoning are impaired speech, irregularity of muscular action, and visual disturbance.
Mercury poisoning from chronic exposure to metallic and inorganic forms of mercury can cause nervousness, fatigue, tremor, and mucous membrane irritation. Inorganic mercury poisoning is associated with gastroenteritis and nephritis. Organic mercury affects the central nervous system with results that may be severe and irreversible.
Chronic inorganic mercury poisoning is an occupational disease of smelters, mercury miners, gilders, and factory workers. Inhalation of mercury vapors may lead to inflammation of the lungs causing cough, fever, and other pulmonary symptoms. The most reliable way to measure exposure to inorganic mercury is in a 24-hour urine sample.
The most common nonindustrial source of mercury poisoning is the consumption of methylmercury-contaminated fish. Organic mercury poisoning is best detected in whole blood, as this form of mercury is located mainly in red blood cells. Organic mercury poisoning may develop quickly or slowly, and can cause serious disease.
Pregnant women are especially sensitive to mercury. Approximately 6% of childbearing-age women have levels that can do harm (>5.8 ?g/L, the FDA allowed level) to mother and child. Women who are pregnant or who intend to become pregnant should not over-consume fish, and should never eat fish from contaminated waters.
Elemental mercury is usually quite harmless if touched or swallowed. It is so thick and slippery that it usually falls off your skin or out of your stomach without being absorbed. Considerable damage can occur, however, if mercury goes airborne in small droplets and is breathed into the lungs.
This can often occur by mistake when people try to vacuum up mercury that has spilled onto the ground, or when a dentist is grinding or polishing mercury fillings. Breathing in elemental mercury can have an immediate effect. Symptoms can also occur over time if small amounts are inhaled every day.
Symptoms of elemental mercury toxicity include:
- Metallic taste
- Difficulty breathing
- Bad cough
- Swollen, bleeding gums
Inorganic mercury is poisonous when swallowed. If inorganic mercury enters your blood stream, it can attack the kidneys and brain. Overdose may cause massive blood and fluid loss from diarrhea, kidney failure, and death.
Symptoms of inorganic mercury toxicity include:
- Burning in the stomach and throat
- Bloody diarrhea and vomiting
Organic mercury causes problems over years or decades, usually not immediately. Cumulative exposure to small amounts of organic mercury over time may cause symptoms to appear later, making it difficult for your doctor to diagnose the cause of your illness.
Long-term exposure to organic mercury can cause:
- Numbness or pain in the skin
- Uncontrollable shaking or tremor
- Inability to walk well
- Blindness and double vision
- Memory problems
- Seizures and death
Tracking The Effects of Mercury
Once mercury enters the body, it buries itself in organs and tissues. It hides in the cells of your brain, heart muscles, nerve endings, and invades bones and fatty tissue. This process is insidious, eroding your wellness and progressively damaging your health. Because most mercury does not circulate freely in the bloodstream or urine where it’s easy to find, conventional testing methods—such as a standard blood, urine or hair sample testing—do not detect mercury adequately. You have to bring it out from hiding in order to measure it.
The most accurate way of testing mercury is called the provoked challenge test. This test was developed in the 1950s, however, and in my opinion, is outdated. It uses a strong chemical reaction to force mercury out of bones and other tissues. I find it too harsh for mercury-sensitive people, and therefore it should not be used on children, the elderly, or those with complex chronic debilitating conditions like Lyme Disease or Multiple Sclerosis.
The Future of Envirogenetics
Mercury toxicity can impair memory, the ability to learn, and behavior. It can also damage the heart and immune system. Even in small quantities, it can cause birth defects.
No one knows for sure what the threshold dose is that causes mercury to slowly poison cells in the brain and the liver, two organs where it tends to accumulate. Science is getting closer to unraveling important clinical concerns about mercury toxicity, however.
It seems that most of us are born with a genetic defense against exposure to mercury. When working well, this genetic code helps the body expel mercury in about one month. But not everyone carries this gene sequence. Some people carry a genetic mutation that allows their cells to retain mercury for much longer, up to several months, increasing their chance for symptoms.
It’s clear that there is tremendous individual variability in the response to environmental challenges. We simply do not understand why certain people develop disease when exposed to environmental agents like mercury and others remain healthy. Scientists suspect that there are unique gene-to-gene and gene-to-environment interactions. If we could test these, a new window may open up into understanding why we get sick.
Man Versus Mercury
David Ewing Duncan in his book, Experimental Man, takes on the role of “man versus mercury.” He measured his mercury levels, caught some fish, cooked the fish with butter and basil, and ate them. A few days later, he tested his levels again. His mercury level spiked from 4 µg/l to 13 µg/l—well over the EPA’s recommended level of 5.8 µg/l. Does he have the genes to get rid of the mercury in 30 days, or the mutation that will take three months to clear the mercury from his fish dinner?
To run your own experiment, you’ll have to wait for about another year when these tests will be available to tell if you’re a fast or slow eliminator. But why wait? Get tested now using available blood, urine, or hair tests if you suspect mercury accumulation.
Since no amount of mercury is acceptable, and because of the serous health consequences of heavy metal toxicity, I believe that everyone should test for environmental exposure for mercury, arsenic, lead, cadmium, and aluminum. If your levels are high, see your doctor right away. If they are within range, but not at the optimal zero or undetectable level, consider genetic testing. Then, talk with a naturopathic doctor to determine whether intravenous or oral detoxification therapy is the best method for you.
And, when the new genetic tests are available, check to see if you have the mutations that make you a slow eliminator.
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