With obese people generally considered to be at a higher risk for developing Alzheimer's, the research raises questions about whether the findings are potentially applicable to humans.
"This is the first indication that modest changes in the normal diet can slow some aspects of Alzheimer's disease," said Caleb Finch, co-author of the study published in the online version of the journal Neurobiology of Aging.
"But that is far and away yet to be proven for humans. It's a big jump to say that what's true for a mouse in a cage is relevant to people living in our complex world," Finch said.
In the study, conducted with collaborators at the University of South Florida in Tampa, researchers used mice whose DNA had been altered with human genes from two families with early onset hereditary Alzheimer's.
The mice were then split into two groups as young adults: one that could eat all it desired ("ad libitum") and the other that had its food intake reduced by 40 percent over a four-week period (diet- restricted).
The researchers were looking specifically at the formation of plaques caused by a build-up of the fiber-like substance called beta-amyloid.
Made up of proteins and polysaccharides, amyloid plaques are deposited in the brain during Alzheimer's disease. Specifically, plaques accumulate in the hippocampus and frontal cortex of Alzheimer's sufferers - areas responsible for memory.
In the diet-restricted mice, both the amount and size of plaque was about 50 percent less than in mice that ate as much as they wanted.
"The power of this study is that two different sets of [human] family
mutations were equally sensitive to the effect of diet and slowing the
Alzheimer's-like change," said F
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Contact: Usha Sutliff
sutliff@usc.edu
213-740-0252
University of Southern California
14-Dec-2004