A steady stream of research points to heavy metals (aluminum, iron,
zinc, copper, and mercury) as possibly playing important roles in
Alzheimer's disease. This latest study sheds light on copper:
Copper link to Alzheimer's disease
13:58 12 August 03
Copper may increase the growth of the protein clumps in the brain that
are a trademark of Alzheimer's disease, according to a new US study on
Researchers first noticed that the rabbits they use to model
Alzheimer's disease developed fewer plaques in their brains when they
drank distilled water rather than tap water. These insoluble plaques,
generated in the rabbits via a high-cholesterol diet, are a trademark
of the degenerative illness.
The tap water contained significant amounts of copper, so Larry
Sparks, at the Sun Health Institute in Sun City, Arizona, and Bernard
Schreurs, at West Virginia University, then gave the rabbits distilled
water spiked with copper supplements.
These rabbits developed significantly more plaques than those drinking
only distilled water. They also suffered dramatically poorer memories
in complex tests.
"We believe that this is a two-step process," Sparks told New
Scientist. "Cholesterol causes overproduction of Alzheimer's proteins
and then copper inhibits the clearance of beta-amyloid [a
plaque-inducing protein] from the brain to the blood."
"The most striking thing was probably the fact we got full blown
plaques in the brains of [these rabbits] which were regionally
distributed similarly to Alzheimer's," he says.
Harriet Millward, deputy chief executive of the UK's Alzheimer's
Research Trust, says a link between copper and Alzheimer's has been
suggested before but that research so far has been contradictory.
"These are certainly interesting results - but we still need more
research," she told New Scientist. She also notes that using
cholesterol-fed rabbits as a model for Alzheimer's disease is a "very
In the latest experiments, the cholesterol-fed rabbits were given
water laced with 0.12 parts per million copper, one tenth of US safety
limit for humans. Three-quarters of the rabbits showed senile
plaque-like deposits in their brains after 10 weeks. These rabbits
also showed an 80 per cent deficit in memory in complex conditioning
The plaques were not found in the brains of animals given pure
distilled water and were rare among those drinking tap water.
"Although we can only speculate about how the effects of copper
consumption in cholesterol-fed rabbits relate to those in humans, it
is of note that the levels of copper ... that induced beta-amyloid and
senile plaque-like structures are well below those considered safe for
humans," Sparks and Schreurs write in Proceedings of the National
Academy of Sciences:
Sparks says the pair are now working on understanding the mechanism by
which copper might cause beta-amyloid to accumulate in the brain.
Ashley Bush and colleagues at Harvard Medical School have previously
proposed a different mechanism by which metals like copper and zinc
could cause Alzheimer's (New Scientist print edition, 3 August 2002).
They have suggested that the metals may cause beta-amyloid to turn
into a rogue enzyme, catalysing the production of hydrogen peroxide,
which then damages brain cells.
Journal reference: Proceedings of the National Academy of Sciences
Aluminum and Alzheimer's disease:
Iron and Alzheimer's disease:
Mercury and Alzheimer's disease:
"To lengthen thy life, lessen thy meals." Ben Franklin
Ongoing CR-monkey-study update: "In the monkeys...those on
reduced feeding since the study started are dying at a rate
that is about half that of the monkeys receiving a full food
ration." Associated Press: Eating less may extend human life.
August 1, 2002 : http://www.msnbc.com/news/788746.asp?0si=-