Researchers at Banner Sun Health Research Institute (BSHRI) has found further evidence linking copper to the increased probability of developing Alzheimer's disease, according to a study published in the current issue of the International Journal of Alzheimer's Disease, vol. 2011, Article ID 987023.
While the cause and progression of Alzheimer's disease are not completely understood, researchers believe the dementia is associated with plaques and tangles in the brain. In studying the brains of those with the disease, researchers have found gatherings of a substance called amyloid and tangled clumps of an additional protein formed when cells die, called tau.
The study, led by BSHRI researcher Dr. Larry Sparks, employed a cholesterol-fed model of Alzheimer's disease to investigate the relationship between Alzheimer's disease-like neurofibrillary tangle (NFT) neuropathology and tau protein levels as the main component of NFT. Researchers measured brain and plasma tau levels and semi-quantified NFT-like neuropathology in cholesterol-fed rabbits administered drinking water of varying quality – distilled, tap and distilled with copper – compared to animals receiving normal food and local tap water.
"Total tau levels in plasma were increased in all cholesterol-fed rabbits compared to animals on normal chow, regardless of quality of water," said Sparks. "These studies suggest the possibility that circulating tau could be the source of the tau accumulating in the brain."
Previously, copper has been implicated in the progression and possibly the cause of Alzheimer's disease as studies have shown the that increased copper intake significantly increases the rate of progression of Alzheimer's disease in the setting of elevated fat intake.
In the BSHRI study, Sparks and his team performed a pilot study of long-term dietary cholesterol in four groups of rabbits. One group was administered normal food and water and three groups were administered increasing levels of a cholesterol diet for five months. Significantly, plasma levels of tau increased by 40 to 50 percent in each of the cholesterol-fed animal groups after five months of the experimental diet.
"This is the first study of the effect of intake of copper or trace metals on levels of the protein tau in the blood and brain," Sparks added. "We have shown that there is increased tau neuropathology associated with increasing levels of tau in the blood and brain of the cholesterol-fed rabbit."
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