Dr. Jay Heinecke, professor in the University of Washington's Department of Medicine, reveals how new research suggests HDL, the "good" cholesterol, may also have a harmful side. Renowned for its ability to protect against heart disease, scientists have found the protein composition of HDL plays an important role in whether this kind of cholesterol is helpful or dangerous. A better understanding of these proteins could lead to new, more accurate tests for predicting or evaluating heart disease. To see more videos from the University of Washington visit uwtv.org.