The latest findings of the University of Calgary in Canada about how the mercury in your dental fillings can make you ill.
In Vol. 1 No 5, WDDTY presented the story thus far with respect to the amalgam debate. Chief among the architects of that debate is Dr Murray J. Vimy, clinical associate professor of the Department of Medicine, the University of Calgary in Alberta, Canada, who with his colleagues has spent a decade examining the effects of amalgam fillings on sheep, monkeys and, more recently, humans. Although 12,000 papers have been published to date on the dangers of amalgam, it is only with the interest of respected medical departments like Dr Vimy's and their devastating findings that the issue is hotting up, particularly in North America.On 14 April, Dr Vimy presented a one day seminar at no less a conservative venue than the British Dental Society, to a packed audience. The seminar had been organized by WDDTY panel member Jack Levenson, president of the British Dental Society for Clinical Nutrition, who has galvanized the fight against amalgam fillings in the UK.
Those of you who have read our earlier issue may remember that Dr Vimy and his colleagues placed amalgam fillings in eight adult sheep. One month later, substantial quantities of mercury appeared in the lung, the gastrointestinal tract and the jaw tissue. Once absorbed, the mercury rapidly settled into the liver and kidneys (FASEB, the official publication of the Federation of American Societies of Experimental Biology, December 1989). The fillings employed radioactive amalgam, which would both guarantee that the mercury could be easily located and also eliminate the need for a control, since there wouldn't be the same radioactivity present in water or food.
In a later study, Dr Vimy and his colleagues placed radioactive mercury in the teeth of pregnant sheep. Two weeks later, the mercury was evident in foetal blood, amniotic fluid, pituitary glands, liver, kidney and part of the placenta. Within a month, most foetal tissue had higher levels of mercury than the mothers did. And during lactation, the mothers had eight times as much mercury in the milk than in their blood serum.
WDDTY attended the April seminar and afterwards discussed the findings with Jack Levenson, our panel member, who chaired the meeting. The evidence that Dr Vimy and his colleagues have published conclusively proves that mercury from amalgam fillings migrates to tissue in the body, causing harm but the extent of the harm is still under study.
Dr Vimy stresses that he is a scientist, who sits squarely in the middle of the amalgam debate between the left, which claims amalgam is responsible for every illness there is, and the right (the dental associations), which turns a blind eye to mounting scientific evidence. "The evidence shows there is some risk, we're not sure of the extent of the risk, but it certainly is prudent to study and consider it, " he says.
What follows here and in the guest column on root canal fillings (p 3) is evidence that relies primarily on research conducted on animals. Although we at WDDTY do not support animal experimentation per se, virtually all the study being done on amalgams is being performed solely on animals. We present it without endorsement because it is among the most important scientific evidence of amalgam fillings to date, and Dr Vimy and his colleagues, among the most prestigious groups studying the issue. Here, then, are the highlights of a day packed with studies and statistics. Editor.
"The denser the tissue, the larger the volume." In Dr Vimy's initial experiments on sheep, the radioactive mercury landed in the stomachs, liver, left and right kidneys in other words, in the oral cavity, the lungs and the gastrointestinal (GI) tract. The denser the mass of tissue, the more mercury collected there.
Sheep were originally chosen for the Universary of Calgary's original study because they are especially ruminant that is, they chew all day. Dr Vimy's team felt that if mercury didn't go into the tissues and organs of sheep, it wouldn't go into the tissues or organs of any living creature. "Sheep," he sums up, "were a worst case scenario."
"What's true for sheep is true for monkeys." Dr Vimy and his colleagues were criticized ridiculed is more the operative word for using sheep because they have a higher frequency of chewing than humans and more than one stomach and so more bacteria for digestion. (Headlines in the medical press tended to disparage the findings, like one that said: "Sheep Baaad Amalgam Recipients"). So Dr Vimy's group decided to repeat its experiment in monkeys. The researchers chose monkeys because their rate of chewing was more similar to humans, as is their teeth, their diet, feeding frequency, chewing pattern and organ physiology. They found the same pattern of mercury depositing in the oral, lung and GI tract of monkeys that they had seen in sheep. "If the information we have about the effect of amalgam fillings were presented before the Food and Drug Administration today, they would not pass it for use because it hasn't passed the animal tests," said Dr Vimy.
"That's like walking around with one kidney." In 1990 Dr Vimy and his researchers conducted another sheep experiment, the results of which were published in the American Journal of Physiology (261:R1010). Because mercury tends to migrate primarily to organs like the kidneys, they wished to find out its effect. After placing regular (rather than radioactive) fillings into the mouths of several sheep, Vimy's group measured the flow rate of inulin, a starch, through the sheep's kidneys. This is a standard index of kidney function, since inulin is neither secreted or absorbed. "Basically, we found that 30 days after the placement of amalgam fillings, kidney function and its filtration capacity was reduced by 50 per cent," Dr Vimy said. "We had placed glass ionomer (white plastic) fillings into control animals, who showed no change in kidney function.
"We also found a rapid rise in sodium in the urea, even though we had restricted the sodium diets of the animals by 300 per cent. So that showed us that sodium was lost. And we found a rapid decline in albumin excretion by 68 per cent.
"What this means," Dr Vimy added, "is that the reabsorption of urea was impaired. The albumin levels meant that kidney blood flow was reduced."
"We also noticed problems with gut bacteria and an association between resistance to antibiotics and high mercury content." The University of Calgary team combined forces with Dr Ann Summers and her colleagues in the Microbiology Department of the University of Georgia in Athens, Georgia, who are expert in matters concerning the gut. Calgary sent their raw statistics on the six monkeys for Summers et al to analyze in terms of the effect of mercury on intestinal flora.
The University of Georgia found increased mercury resistant bacteria in monkey gum and intestinal bacterial flora after the placement of dental fillings. In the past, Dr Summers has shown that when there is a high mercury resistance in the bacteria in the gut there is also a high multiple antibiotic resistance.
To greatly simplify, what happens is that the presence of mercury creates a change in the chemical makeup of the some two and a half pounds of "friendly" bacteria living in the intestine, making it resistant to antibiotics. This means that the bacteria, which are essential for the smooth operation of the immune system, are, in Jack Levenson's words, "otherwise engaged" and no longer able to keep fungi like candida albicans in check. It also enhances the reabsorption of mercury vapour, says Dr Vimy, as it migrates from the teeth. This sets up a basic dysfunction in the gut, adds Levenson, which could be responsible for candida and the proclivity of allergies suddenly developing in people in their middle years.
"There is increasing evidence that mercury, rather than aluminium, is the highest trace element found in the brains of Alzheimer's disease victims." W. R. Markesbery et al, a medical research team at the University of Kentucky in Lexington, Kentucky, has been investigating Alzheimer's disease (AD) and its association with mercury for several years. In their most recent study (published in Brain Research 553, 1990) they studied the brains from 10 autopsied AD patients for concentrations of trace elements. The highest trace element was consistently mercury, with diminished zinc and selenium levels. They concluded: "The present study suggests that the elevation of mercury in AD is the most important of the imbalances we have observed." They considered the lower zinc levels significant since zinc and selenium are known to have a protective role against heavy metal toxicity in tissue.
Their results were supported by the work of B. Haley et al, published in FASEB in April 1991. Tubulin is a protein which is needed for the healthy formation of neurofibrils, or connective nerve tissue. AD patients have impaired tubulin, which causes what is known as a "neurofibril tangle", meaning that messages in the brain don't connect properly. In one of their studies, the researchers fed rats aluminium, usually considered the causative factor of AD, but observed no change in tubulin levels, whereas mercury fed rats displayed a similarly diminished tubulin level as AD patients. "These results suggest that certain complex forms of mercury must be considered as a potential source of the etiology of AD," the authors concluded.
Aluminium may well be a red herring in the quest to find the cause of AD. It could be, as some suggest, that a brain depleted of zinc and overwhelmed by mercury is susceptible to the depositing of aluminium, but that particular heavy metal doesn't cause the problem. Or it could be that both aluminium and mercury contribute to the condition.
"Mercury is associated with the sclerosing diseases." The Journal of Epidemiology and Community Health (32:155: 1978) and the Swedish Journal of Biological Medicine in January 1989 both have showed an association between high mercury levels in patients with multiple sclerosis (MS).
In the latter study, the mercury level in MS patients were on average 7.5 times higher than in the control group. In many of the cases, treatment with antioxidation therapy (ie, vitamins, selenium and or removal of amalgam fillings) helped patients to improve sometimes completely.