HDL is often referred to as good cholesterol, because it helps take “bad” (LDL) cholesterol from the bloodstream back to the liver for removal, protects blood vessels, and acts as an antioxidant. We used to only be able to measure the amount of HDL, but now, scientists are able to measure how well the HDL is functioning as well. To see how a Mediterranean diet aﬀects HDL function, researchers analyzed data from 296 participants in the PREDIMED trial (a randomized, controlled study where people at risk of heart disease were assigned to either a Mediterranean diet with nuts, a Mediterranean diet with olive oil, or a low fat diet). Both Mediterranean diet groups improved cholesterol eﬄux capacity (how well the LDL is transported out by the HDL). However, the olive oil group also had improved HDL antioxidant properties, and improved blood vessel protection.
Circulation. 2017 Feb 14;135(7):633-643. (Hernaez A et al.)