Or, your brain may starve.

A new study from Northwestern University's Feinberg School of Medicine has found when the brain doesn't get enough sugar glucose -- as might occur when cardiovascular disease restricts blood flow in arteries to the brain -- a process is launched that ultimately produces the sticky clumps of protein that appear to be a cause of Alzheimer's.

Robert Vassar, lead author, discovered a key brain protein is altered when the brain has a deficient supply of energy. The altered protein, called elF2alpha, increases the production of an enzyme that, in turn, flips a switch to produce the sticky protein clumps. Vassar worked with human and mice brains in his research.

The study is published in the December 26 issue of the journal Neuron.

"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 Vassar, a professor of cell and molecular biology at the Feinberg School.

A simple preventive strategy people can follow to improve blood flow to the brain is getting exercise, reducing cholesterol and managing hypertension.

Exercise helps with hypertension too. Balanced cholesterol (hdl/ldl) seems more important than reduced cholesterol.

Bear this in mind during this time of feasting and reduced outdoor activity, at least for some of those in the N. hemisphere, since it seems to be hard on the brain. The man who splits his own wood warms himself twice, and perhaps will have the wits to appreciate it.