The term "mad as a hatter" will forever be linked to the madcap milliner in Lewis Carroll's classic children's book, Alice in Wonderland. But few actually know that the true origin of the saying relates to a disease peculiar to the hat making industry in the 1800s. A mercury solution was commonly used during the process of turning fur into felt, which caused the hatters to breathe in the fumes of this highly toxic metal, a situation exacerbated by the poor ventilation in most of the workshops. This led in turn to an accumulation of mercury in the workers' bodies, resulting in symptoms such as trembling (known as "hatters' shakes"), loss of coordination, slurred speech, loosening of teeth, memory loss, depression, irritability and anxiety -- "The Mad Hatter Syndrome." The phrase is still used today to describe the effects of mercury poisoning, albeit from other sources.

These days, we are infinitely more aware of the deadly toxicity of mercury exposure, yet mercury remains more common than one might think. Mercury can be found in our cars, homes, food, medicine cabinets -- even in our mouths. The biggest challenge with diagnosing heavy metal toxicity is its indolent, slow, smoldering effect that never lets the affected know that mercury is the root of the problem. Exposure to mercury begins in the womb, where the mother transfers mercury to the fetus through the placenta. Once the fetus is out of the uterus, there are many ways for mercury levels to begin to accumulate. Common items that mercury can be found in include:

Pesticides Paint pigments and solvents Fertilizers Cinnabar (used in jewelry) Amalgam (silver fillings) Laxatives Drinking water (tap and well) Cosmetics (mascara) Auto exhaust Floor waxes and polishes Felt Wood preservatives Plumbing (piping) Adhesives Bleached flour Batteries Processed foods Air conditioner filters Fabric Softeners Fish Calomel (talc, body powder)

Mercury and Dental Health

If you are like most Americans, or most people in the world for that matter, you probably have mercury and/or other metal fillings in your mouth. Mercury fillings, also known as "silver fillings" or "amalgam," are the most common fillings in the world. Called silver because of their color, they actually contain 45 to 52 percent mercury. Copper, tin, silver and zinc make up the remaining volume.

Some interesting facts related to the common dental filling (amalgam):

Scientific research has demonstrated that mercury, even in small amounts, can damage the brain, heart, lungs, liver, kidneys, thyroid gland, pituitary gland, adrenal gland, cells, enzymes and hormones and suppress the body's immune system.

Mercury is continually released from mercury dental fillings in the form of mercury vapor and abraded particles. These mercury vapors can increase as much as 15-fold by chewing, brushing, drinking hot liquids, etc. The World Health Organization recently concluded that the daily intake of mercury from amalgam dental fillings exceeded the combined daily intake of mercury derived from air, water and food (including fish).

In human autopsy studies, it has been found that there is a direct correlation between the amount of mercury found in the brain and the number and surfaces of mercury fillings in teeth.

Mercury causes normal intestinal micro flora to become mercury resistant and antibiotic resistant. In the intestinal tract, mercury-resistant bacteria cause mercury to be converted back into vapor and then recycled back into the body. Antibiotic resistance is becoming a major medical concern.

Recent scientific research has shown high levels of mercury in the brains of individuals who died from Alzheimer's disease. Other research demonstrates mercury can cause pathological effects in the brain similar to those seen in Lou Gehrig's disease. Laboratory studies of spinal fluid from Alzheimer's and Lou Gehrig's disease patients have confirmed that mercury inhibits key brain detoxification of enzyme systems.

A Brief History of Mercury Fillings

In the early 1800s, French dentists were the first to discover that mixing silver with mercury would allow the amalgams to bond at room temperature. This practice was introduced to American dentists in the 1830s and was widely denounced due to the associated dangers of mercury exposure. In 1840, the American Society of Dental Surgeons (ASDS) formed, requiring its members to sign pledges promising not to use amalgams . This led to much strife amongst the members, culminating in the suspension of 11 dentists in New York when the ASDS found them guilty of amalgam use. By the mid 1850s, the ASDS disbanded as a result of the internal debate. In 1859, the American Dental Association was formed and did not take a stand on the amalgam issue. Today, the ADA states that amalgams are safe and do not present a health threat, despite the fact that, in 1989, the Environmental Protection Agency declared amalgams a hazardous substance. The debate rages on today.

Removing Mercury Fillings

If mercury is so dangerous, shouldn't everyone run out and have their dental fillings removed? The answer is a great big "NO!" The process of removing amalgams can generate mercury vapor and particulates many times greater than leaving them alone. Before making a decision to have your fillings removed, have your physician screen your body with a simple urine test to measure the level of toxic heavy metals in your body. If it is determined that your levels are high, it is recommended that you consult with a biological dentist who is knowledgeable in safe amalgam removal.

Chelation Therapy as a Treatment Option

You should be aware of the fact that there are alternative techniques to treat metal toxicity problems, such as chelation therapy. In most instances, the general population knows nothing about such treatments because the traditional medical establishment isn't aware of its existence and/or such knowledge has been suppressed over the years by various powerful organizations.

Chelation was first used in the 1940s by the U.S. Navy to treat lead poisoning and was subsequently approved by the FDA as a safe method of treating heavy metal toxicity. Chelation therapy is a medical treatment that improves metabolic and circulatory function by removing toxic metals and abnormally located nutritional metallic ions (such as iron) from the body. This is accomplished by administering an amino acid, ethylene-diamine-tetra-acetic acid (EDTA), by either an oral or intravenous infusion.

When a molecule of EDTA travels through the blood stream, it grabs on to the heavy metal particles, binding tightly and pulling them out of the membrane or body tissue in which they are embedded. Since EDTA is an artificial amino acid, the body regards it as a foreign substance and delivers it to the kidneys to be excreted in the urine.

Physicians familiar with the administration of chelation therapy treatment alternatives can thoughtfully review the benefits of undergoing such therapeutic treatments with their patients.

Dr. Connealy, M.D., M.P.H. began private practice in 1986. In 1992 she founded South Coast Medical Center for New Medicine, where she serves as medical director. Her practice is firmly based in the belief that strictly treating health problems with medications does not find the root cause of the illness. Dr. Connealy writes monthly columns for Coast and OC Health magazines and is a biweekly guest on Frank Jordan's "Healthy" radio show. She routinely lectures and educates the public on health issues.

Mercury Fast Facts:

Mercury is the most toxic non-radioactive element on earth.

A silver-colored mercury amalgam filling normally contains 52 percent mercury.

On average, amalgam fillings weigh 1 gram and contain ½ gram of mercury.

The typical adult carries 10 amalgam fillings containing 5 grams of mercury.

Half a gram of mercury in a 10-acre lake would warrant issuance of a fish advisory for the lake.