Scientists have found that when the brain is slowly starved of glucose over time, some forms of Alzheimer's disease may result.

Researchers used human and mice brains to study how a reduction in blood flow deprives the brain of energy. The chronic starvation eventually leads to sticky clumps of a protein linked to Alzheimer's, the leading cause of dementia in the elderly, they found.

"This finding is significant because it suggests that improving blood flow to the brain might be an effective therapeutic approach to prevent or treat Alzheimer's," said the study's lead author, Robert Vassar, a professor of cell and molecular biology at Northwestern University in Chicago.

It's possible that preventive strategies such as getting exercise, reducing cholesterol and managing blood pressure could help prevent Alzheimer's by improving blood flow to the brain.

"If people start early enough, maybe they can dodge the bullet," Vassar added in a release.

In the Dec. 26 issue of the journal Neuron, Vassar and his colleagues said they discovered a protein called elF2alpha that is changed when the brain fails to get enough energy in the form of glucose.

'Slow, insidious process'

When starved, more of an enzyme is made that in turn leads to sticky protein clumps, called amyloid plaques, to be produced.

The findings suggest that Alzheimer's disease may result from a less severe type of energy deprivation than in strokes.

Instead of dying, brain cells react by boosting production of the enzyme, called BACE 1, which Vassar said may be a protective response in the short term, but harmful over the long term.

"What we are talking about here is a slow, insidious process over many years where people have a low level of cardiovascular disease or atherosclerosis in the brain," he said.

"It's so mild, they don't even notice it, but it has an effect over time because it's producing a chronic reduction in the blood flow."

Future experiments will determine whether blocking the pathway could be used as a therapeutic approach to prevent and treat Alzheimer's, the researchers said.

In 2008, an estimated 97,000 Canadians will develop Alzheimer's or a related disease, and an estimated 450,000 Canadians have it or a related disease, according to the Alzheimer Society of Canada.

The disease slowly leads to memory impairment, behavioural changes and dementia, affecting how people understand, think, remember and communicate.