Cholesterol has a big hold on medical practice because it is so easy to measure. Unfortunately standard medical practice hasn’t kept up with advances in the measurement of cholesterol. The total amount cholesterol in LDLs (low-density lipoproteins)—so-called “bad cholesterol”—and the total amount of cholesterol in HDLs (high-density lipoproteins)—so-called “good cholesterol”—are routinely reported. but there is much more to the story.

Somewhat confusingly, within the category of low-density-lipoprotein (LDL) particles, it is the small, dense ones that are most dangerous. A 13-year follow-up report on the Québec Cardiovascular Study (“Low-density lipoprotein subfractions and the long-term risk of ischemic heart disease in men: 13-year follow-up data from the Québec Cardiovascular Study”) summarized its conclusions thus:

These results indicated that estimated cholesterol levels in the large LDL subfraction were not associated with an increased risk of IHD in men and that the cardiovascular risk attributable to variations in the LDL size phenotype was largely related to markers of a preferential accumulation of small dense LDL particles.

In other words, big LDL particles that hold a lot of cholesterol aren’t associated with extra risk of blockage of blood to the heart; small dense LDL particles that may not hold that much total cholesterol account for pretty much all the risk of reduced blood flow to the heart that we associate with LDL cholesterol.

Unless you are quite lucky, your doctor is unlikely to do tests that distinguish between the small, dangerous LDL particles and the large, relatively innocuous LDL particles unless you ask for them. I have no idea how it stacks up with other testing companies, but the Quest Diagnostics webpage I show below is one that you could refer your doctor to for general orientation about a variety of more sophisticated tests of cardiovascular risk, including tests that better distinguish different subtypes of cholesterol particles.

I recommend that you get these more modern tests. You definitely should get these tests if your doctor is recommending any treatment for cholesterol. But you also should get these tests to make sure you aren’t lulled into a false security by the standard cholesterol test.

I learned about these more sophisticated tests of cardiovascular risk from Peter Attia’s podcast. As I have on other occasions let me strongly recommend Peter Attia as a very thoughtful and well-informed source for health knowledge.

For organized links to other posts on diet and health, see:

• Miles Kimball on Diet and Health: A Reader's Guide