If you’re one of the crowd, dental fillings likely aren’t on your—or your doctor’s—short list of possible causes. But mercury in the fillings you got last week, or even decades ago, might well be the cunning culprit.Got fatigue? How about depression, memory loss, ulcers, insomnia, or irritability? Millions of Americans do.
If you think this is impossible, considering all the federal and state agencies and regulations out there to protect us, think again. The U.S. government restricts mercury in the food we eat, the water we drink, and the air we breathe, but does not regulate the number one source of human mercury expo- sure: mercury amalgam (silver) fillings.
There are three chemical forms of mercury—elemental, which is in dental amalgam; inorganic, which was once commonly available in thermome- ters; and organic, which is converted from inorganic mercury by microorganisms in soil and water. All forms of mercury are toxic to humans.
Dental amalgam is made of nearly equal parts of liquid mercury, generally about 50% by weight, and a powder containing silver, tin, copper, zinc and other metals. A recent national poll by Zogby International indicated that over 75% of consumers don’t know that mercury is the main ingredient in “silver” fillings.
According to the Food and Drug Administra- tion, “Dental amalgam contains mercury, which may have neurotoxic effects on the nervous system of developing children and fetuses. When amalgams are placed in teeth or removed from teeth, they release mercury vapor. Mercury is also released during chewing.”
“Silver” fillings are actually composed of 50% mercury, and are less than 30% silver.
Deadlier than arsenic and lead, mercury is the most toxic non-radioactive element on earth. It occurs naturally in the earth’s crust, but has no role in the human body. Mercury toxicity was revealed to the world in dramatic fashion in the mid-1950’s in the Japanese fishing village of Minamata. There, more than 12,000 people (some estimates go as high as 100,000) suffered serious mental and physical disorders, including convulsions, hearing and speech loss, brain damage, numbness, and joint pain, due to contamination of fish and seafood by mercury dumped for decades into Minamata Bay from a chemical plant. Eventually, 2000 people died and the local ecosys- tem and economy were decimated. Severe mercury poisoning was named Minamata Disease in the wake of the disaster.
Today, a large body of scientific and medical research shows harm in mercury exposures much lower than Minamata levels. In the list of known symptoms of chronic, low-dose exposure. (See the symptoms table on the next page.) America’s most common health complaints—including fatigue and head- aches—feature prominently.
Studies have also tied chronic mercury exposure to autism, Alzheimers, kidney and lung disease, diabetes, candidiasis, and auto-immune disorders such as multiple sclerosis, rheumatoid arthritis, and thyroiditis.
The wide-ranging effects are due in part to mercury’s ability to cross the blood-brain barrier. In its most toxic form, as methyl mercury vapor, the element dissolves in the blood and is carried throughout the body into all tissues and organs. Damage occurs at the cellular level, with the central nervous system being especially susceptible.
For fetuses, infants, and children, the primary health effects are neurological. Mercury in a woman’s body can be passed to a developing fetus through the placenta or in breast milk, causing birth defects and complications related to memory, attention, and language. Young children exposed to mercury in combi- nation with other heavy metals in their environment (such as lead in lead paint) may be harmed in ways not yet fully understood.
Because mercury occurs naturally in the environment, everyone is exposed to very low levels. In the minds of the general public, levels high enough to have health effects are generally associated with industrial wastewater discharges and air emissions from coal burning power plants, contaminated food fish, and the mercury-based preservative thimerosol used in vaccines.
Confirmation by the World Health Organization that dental amalgams are the greatest common source of human elemental mercury expo- sure is not widely known, though the evidence is solid. Dental amalgams as old as 25 years have been shown to release significant mercury vapors upon stimulation by eating, drinking hot bever- ages, tooth brushing, flossing, and—no surprise—dental work. Grinding and drilling out old mercury amalgam fillings can generate not only vapors that can be inhaled but also minute mercury particles that can be swallowed and absorbed in the intestines.