Nutrition Science and Everyday Application - beta v 0.1

292 ALICE CALLAHAN, PHD, HEATHER LEONARD, MED, RDN, AND TAMBERLY POWELL, MS, RDN
Fig. 5.28. Atherosclerosis. (a) Atherosclerosis can result from plaques formed by the buildup
of fatty, calcified deposits in an artery. (b) Plaques can also take other forms, as shown in this
micrograph of a coronary artery that has a buildup of connective tissue within the artery wall. LM
× 40. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)
Physicians sometimes run additional blood tests to measure the LDL particle size and the
number of LDL particles. The standard LDL test measures the total amount of cholesterol
that is carried by LDL, but the reality is that LDL comes in a range of sizes, and small LDL
particles are more strongly associated with the risk of atherosclerosis and cardiovascular
disease than large LDL particles. For two people with the same total LDL cholesterol
measurement, a person with more small particles will have a greater number of LDL particles
circulating and a higher risk of developing heart disease. A person with more large LDL
particles will have fewer particles overall and a lower risk of developing heart disease.
Measuring particle size is not recommended for all patients because of the cost of the test
and the fact that it rarely changes treatment course or improves outcomes. However, it can
be useful in patients with diabetes or insulin resistance, as they tend to have more small LDL
particles, which may call for using medications sooner or in higher doses.
HDL has been considered the “good cholesterol” or “good cholesterol transporter”
because it scavenges cholesterol, including LDL lodged in the arterial walls, and helps
to remove it from the body. Previously, it was thought that high HDL could prevent
atherosclerosis and protect people from cardiovascular disease. But over the last few years,
researchers have discovered that this view of HDL is oversimplified. Pharmaceutical
companies developed drugs to raise HDL, thinking this would help to prevent cardiovascular
disease. When these medications were tested in clinical trials, they were effective at raising
HDL, but they didn’t decrease the incidence of heart attack, stroke, angina, or death from
cardiovascular disease. 1 In one clinical trial, the incidence of cardiovascular events and death
from any cause were actually increased in people who took the HDL-raising medication (2).
Genetic studies have also shown that people with genes for higher HDL don’t necessarily
have a lower risk of developing cardiovascular disease. 3 People with low HDL cholesterol