Health campaigners have for years blamed amalgam fillings for a host of neurological disorders, from impaired mental development to Alzheimer's disease. But a new study by German scientists suggests that many people who complain about the side effects of amalgam are unwittingly using it as a scapegoat for disorders that have other causes.
Opponents of the use of amalgam-which contains mercury and another metal such as silver-claim it leaks mercury into the body. Mercury is a toxic metal that can affect the nervous system even at low levels. Children born to mothers who had low levels of the metal in their blood during pregnancy had deficiencies in learning, memory and attention (see This Week, 22 November 1997, p 4). German health minister Andrea Fischer announced last month that she is planning to look again at the concerns surrounding the alloy and will ban it if doubts over its safety emerge.
Anton Rudolf and Josef Bailer, psychologists at the University of Heidelberg at Mannheim, and others looked at 40 patients who were complaining of health problems connected with their amalgam fillings, such as headaches, anxiety and lack of concentration. They compared them with 40 others who had a similar number of fillings but no complaints. When they measured mercury concentrations in the saliva, blood and urine of the subjects, they found very low levels in all of them and no difference between the two groups.
However, the researchers found that a high proportion of the complainants had histories of psychological problems, compared with few of the others. These people tended to be emotionally unstable, showed depressive symptoms and a slightly obsessive attitude towards their body and health, says Rudolf. He believes that while they were not imagining their symptoms, if they had not heard in the media that amalgam may be harmful, they would have looked for other causes to blame for their symptoms.
Concern over the effects of amalgam is apparently widespread. When the researchers asked 1000 people in the Frankfurt area about their attitudes towards it, 23 per cent said they thought the alloy posed a considerable hazard to their health.
Christof Schumacher, spokesman for the German Dentists' Institute in Cologne, says that amalgam is not without its risks. But he points out that other materials used for filling have drawbacks too.
Source: New Scientist issue 6th Feb. 1999