Harvard Heart Letter

A road map to life in the fat lane

The path from hamburger and French fries to artery-narrowing atherosclerotic plaque is a tortuous one with several participants and cycles. You have probably heard about the particles involved, but you may not know how they are connected or what happens to them as they course through the bloodstream. Here's a road map that may help.

Like a highway at rush hour, your bloodstream carries many sizes and shapes of the fat-transporting particles known as lipoproteins. The more fat they contain, the lighter and fluffier they are, and the lower their density. The largest particles are the chylomicrons. Their job is to deliver high-energy fat in the form of triglycerides to cells throughout the body. Very-low-density lipoproteins (VLDL) also transport fats to the body's tissues. As triglycerides are drained from VLDL particles, they become smaller, denser, and pick up new proteins for their outer coats. Through this process they morph into low-density lipoproteins (LDL), often referred to as bad cholesterol. High-density lipoproteins (HDL), sometimes called good cholesterol, sponge up excess cholesterol from the lining of blood vessels and carry it to the liver for recycling or disposal. HDL also appears to do a host of other things that protect the arteries, such as protecting LDL from oxidation, calming inflammation, and keeping atherosclerotic plaque from breaking apart.

To continue reading this article, you must login.
  • Research health conditions
  • Check your symptoms
  • Prepare for a doctor's visit or test
  • Find the best treatments and procedures for you
  • Explore options for better nutrition and exercise
Learn more about the many benefits and features of joining Harvard Health Online »