I've studied the mercury thing a little and other nutrition/toxicity issues a little more. One problem with mercury toxicity research is that mercury occurs much more in fish than most other food sources, but fish themselves 1) contain many contaminents....not just mercury and 2) fish contain many nutrients, such as omega 3 fatty acids, that are very healthy for you. Thus, its hard to tell what causes what and what prevents what. The omegta 3's, in fact, are thought to be potentially protective of nervous tissue that would be damaged by mercury. So eating fish can help protect your nervous system or hurt it, depending on how you look at the research. One thing is for sure: The western diet is currently far lower in omega 3's than its been historically. Omega 3 deficiency has been linked with many diseases that plague our country, including coronary heart disease, diabetes and multiple sclerosis, among others.

Old amalgam fillings may pose more mercury danger than eating fish, depending on who you talk to. Mercury was banned in American densistry before the ADA came along because of neuro toxicity. I believe it is currently banned in some European counrties. When fillings start to break down, or when a tooth cracks, mercury can enter the bloodstream. I didn't know, until recently, that the amalgam fillings I got as an adolesant have limited life (~10 to 20 years) and should be replaced periodically.