Mercury Crosses Blood-Brain Barrier

Townsend Letter for Doctors and Patients, Jan, 2001 by Jule Klotter

The blood-brain membrane barrier prevents many toxins in circulating blood from infiltrating the brain and cerebrospinal fluid, but it does not prevent heavy metals from entering the brain via sensory nerves. Researchers at the Maurice Lamontagne Institute (Burlington, Ontario, Canada) and the Swedish University of Agricultural Sciences added mercury to a water tank that housed a group of brown trout and rainbow trout. A second group of trout, in mercury-free water, were injected with mercury solutions. Using whole-body autoradiography, the researchers found that the fish in the contaminated water showed an accumulation of mercury in brain areas that are linked to sensory nerves, nerves which have direct contact with the water. No mercury was found in the brains of fish who received the injections. Previous experiments with rodents found that manganese, cadmium, and mercury can travel from the nose and mouth to the brain via olfactory nerves.

Claude Rouleau, PhD, at Canada's National Water Research Institute (Burlington, Ontario), the study's primary investigator, said: "The fact that mercury is transported along fish nerves can be extrapolated to humans, as nerve transport also occurs in mammals, including humans....Thus, mercury and other toxins could possibly accumulate in human brains via nerve transport." This report was published in Environmental Science and Technology (Oct. 1, 1999;33), a peer-reviewed publication of the American Chemical Society.

" Mercury's Scary Migration" Environment News Service, 10 September 1999

" Mercury reaches brain directly through nerves" www.reutershealth.com, September 21, 1999.