Popular thought about 'good' and 'bad' cholesterol has been called into question by a new study.
A team of researchers investigating cholesterol and lipid transport found that a protein called ABCA1, which is critical for producing 'good' (high-density lipoprotein or HDL) cholesterol, does not operate in the way previously thought.
Instead of governing the first step in the mechanism by which excess lipids and cholesterol are eliminated from the body, the study found that ABCA1 is involved in the second stage.
Lead researcher Robert Schlegel said: "This work really changes our understanding of the mechanics of cholesterol metabolism.
"We can't find any evidence whatsoever to support the popular hypothesis that the ABCA1 enzyme catalyses the movement of PS across the cell membrane to the outer surface of the cell."
The study was published yesterday in the online journal PLoS One.
Low levels of HDL cholesterol increase the risk of heart attack and stroke.