Blood lipids refer to a group of fatty substances present in blood, mainly including cholesterol and triglycerides. There are generally two forms of cholesterols circulating in bloodstream: low-density lipoprotein (LDL) and high-density lipoprotein (HDL). LDLs are rendered“bad”since they accumulate in vessels and may result in blockage. HDLs are rendered “good” since they help to reduce bad cholesterols in bloodstream.