Unhealthy cholesterol levels are linked to one of the key brain signatures of Alzheimer's disease, scientists have learned.
Relative amounts of "good" and "bad" cholesterol in the blood influence the build-up of harmful protein deposits in the brain, a study found.
Experts draw a sharp distinction between "good" cholesterol, or high density lipoprotein (HDL), and its evil twin low density lipoprotein (LDL).
While high levels of LDL can lead to narrowed arteries and heart disease, HDL is protective.
The new research suggests that the effects the two kinds of cholesterol have on the heart may be mirrored in the brain.
"Unhealthy patterns of cholesterol could be directly causing the higher levels of amyloid known to contribute to Alzheimer's, in the same way that such patterns promote heart disease," said study leader professor Bruce Reed, from the University of California.
The findings are published in the journal 'JAMA Neurology'.