The CSIRO describes cholesterol as an “essential type of fat” produced naturally in the liver. It has many important roles and is the initial creator of vital compounds such as vitamin D and testosterone. A cholesterol test or “lipid study” measures cholesterol carried in the bloodstream and is broken down into four components. Not all cholesterol is bad, so all elements need to be considered. A GP will help interpret the results based on individual risk factors.Total Cholesterol
Total cholesterol measures all the cholesterol carried in the blood by lipoproteins. The Heart Foundation considers “high” total cholesterol to be anything over their ideal target of 4.0mmol/L. “In most cases, if your total blood cholesterol is high it is because your LDL is high,” says Shrapnel.
Low-density lipoproteins (LDLs), also called “bad” cholesterol, carry cholesterol to the wall of blood vessels. Too much LDL cholesterol can build up on artery walls in the form of fatty deposits known as plaque. This plaque narrows the artery and can raise the risk of heart attack or stroke.
“A problem arises when too much cholesterol is moving into cells and there is increased risk of coronary heart disease,” explains Shrapnel.HDL Cholesterol
High-density lipoproteins (HDLs), or “good” cholesterol, are the garbage trucks of the bloodstream and take cholesterol off to be excreted. As HDLs help to carry away surplus cholesterol for dumping, Shrapnel warns, “low HDL is a major problem. We need a balance of LDL and HDL – a balance in the movement of cholesterol in and out of the cell.”
Triglycerides are another type of fat. According to Sviridov, “the liver secretes triglycerides, which are the main source of energy for the body – but they also contain cholesterol. While in circulation, triglycerides get consumed, leaving behind a particle with little fat but lots of cholesterol: LDL.” If someone has low HDL combined with high LDL, and their lipid studies also show elevated triglycerides (anything over 1.5mmol/L), then this can be a heart disease risk factor.
Can’t remember all that? My doctor has a useful tip: make the H in HDL stand for “healthy” and the L in LDL stand for “lethal”. Says it all, really.
Total cholesterol <4.0
HDL cholesterol >1.0
LDL cholesterol <2.5