All of your body’s circulating lipid (cholesterol and triglyceride) is packaged in three main kinds of lipoproteins described by their density (how much they weigh for their size). “Low density” lipoprotein (LDL) and “high-density” lipoprotein (HDL) are the ones most people have heard about. “Very low density” lipoprotein is another package that mostly carries triglycerides. You may know your or your child’s “TOTAL cholesterol” number. Total cholesterol = LDL + HDL + VLDL and the devil is all about the details of the relative proportions of each kind of package.
Low-density lipoproteins, or LDL are the primary cholesterol carriers. If there's too much LDL in the bloodstream, it can build up on the walls of the arteries that lead to the heart and the brain. This buildup forms plaque: a thick, hard substance that can cause blood vessels to become stiffer, narrower or blocked. Atherosclerosis is the name for hardening of the arteries and it is a process that starts in childhood if there are too many LDL particles.
High-density lipoproteins or HDL carries excess cholesterol away from the arteries and back to the liver, where it's processed and sent out of the body. It may even help remove cholesterol from already formed plaques.
Very low-density lipoproteins or VLDL don’t carry too much cholesterol but have a lot of triglycerides, so they are only elevated when there is a problem processing fats in the body and triglyceride levels build up too high. Our body’s lipoprotein production starts with VLDL that then gets broken down into LDL and HDL. How much triglyceride is packed into the starting VLDL has a big influence on both the quality and quantity of LDL and HDL, and you can see how interconnected these packages are.
High levels of LDL increase the risk for heart disease and stroke. High levels of HDL can help protect against these diseases. High levels of VLDL are a risk factor mostly because they are associated with lower levels or HDL and higher levels of LDL. It’s all connected!
No routine lipid screening is recommended before age 8 for kids who are physically active, eat healthy foods, don't have a family history of high LDL or triglycerides (VLDL) and/or low HDL and aren't overweight. These kids probably aren't at risk for cholesterol problems. Your doctor can help decide whether you should have your child's cholesterol level checked. By age 9, current recommendations are that all children have either a fasting or non-fasting lipid profile checked.