High-Fat Diet Linked With Impaired Brain Function
Neurobiol Learning Memory 2001;75
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WESTPORT, CT (Reuters Health) Feb 22 - The results of animal studies
suggest that a high-fat, carbohydrate-poor diet may impair brain function
over time, according to researchers at the University of Toronto.

Rats that were fed high-fat diets were slower in learning new tasks
compared with rats fed a standard diet, investigators report in the March
issue of Neurobiology of Learning and Memory. The high-fat diet animals
also performed more poorly on tests of learning and memory.

The study authors, Drs. Carol Greenwood and Gordon Winocur, believe
high-fat diets may hinder brain function by promoting insulin resistance.
"At this point, we believe the link [between high-fat diets and impaired
brain function] is diabetes," Dr. Greenwood said. This theory, she told
Reuters Health, supports work suggesting that diabetics often suffer a
decline in certain mental functions such as long-term memory.

Moreover, Dr. Greenwood and her colleagues have evidence from human studies
that carbohydrates may boost memory. In a small study of older adults, they
found that a "breakfast" of mashed potatoes or barley increased
participants' performance on memory tests.

Dr. Greenwood explained that a diet lacking in carbohydrates reduces the
supply of glucose, which can impede the acetylcholine synthesis.

In the current study, the investigators found that the test performance of
the memory-impaired rats improved after glucose injections.

However, this does not mean that adding carbohydrates to a high-fat diet
will prevent any ill effects on the brain. "My argument," Dr. Greenwood
said, "is to displace the fats with carbohydrates."