Triglycerides, HDL, & LDL Particle Size
A standard cholesterol test measures triglycerides, HDL cholesterol, and LDL cholesterol. But these numbers don't always tell the whole story.
For metabolic health, triglycerides, HDL, ApoB, and the number and characteristics of LDL particles can provide additional information.
High triglycerides combined with low HDL are commonly associated with insulin resistance and metabolic syndrome. This pattern is also associated with more small, dense LDL particles.
Why Triglycerides and HDL Matter
The triglyceride-to-HDL ratio is simple:
Triglycerides ÷ HDL
For example, triglycerides of 80 and HDL of 60 give a ratio of 1.3.
Metabolic researcher Ben Bikman emphasizes this ratio as a simple indicator of metabolic health. In general, lower triglycerides and higher HDL are associated with better insulin sensitivity and metabolic health.
The ratio is useful as a clue, but it is not a stand-alone diagnostic test for insulin resistance or cardiovascular disease.
William Davis and Small LDL
Dr. William Davis, cardiologist and author of Wheat Belly, argues that conventional LDL cholesterol can provide an incomplete picture because it measures the amount of cholesterol carried in LDL rather than the number and characteristics of the particles themselves.
Davis pays particular attention to small, dense LDL particles. He recommends advanced lipoprotein testing, such as NMR testing, which can provide information about LDL particle number and particle size.
Davis also places considerable emphasis on triglycerides. He recommends aiming for triglycerides of about 60 mg/dL or less, arguing that at this level small LDL particles become much less common.
This is a more aggressive triglyceride target than conventional guidelines generally use, but it reflects Davis's broader emphasis on insulin sensitivity and metabolic health.
Lipid researcher Dr. Ronald Krauss has also extensively studied small, dense LDL. His research has helped establish the relationship among higher triglycerides, lower HDL, insulin resistance, and increased small, dense LDL particles.
What About ApoB?
ApoB is increasingly used to estimate the number of potentially artery-damaging lipoprotein particles. Because each LDL and other atherogenic particle carries one ApoB molecule, ApoB provides information about particle number rather than simply the amount of cholesterol the particles contain.
Many lipid specialists consider ApoB a valuable measure of cardiovascular risk.
William Davis takes a different view. He argues that ApoB still does not tell us enough about the characteristics of the particles themselves. He prefers advanced lipoprotein testing, particularly NMR testing, because it can identify small LDL particles and provide additional information about the metabolic conditions that may be producing them.
The two measurements therefore answer somewhat different questions: ApoB estimates how many atherogenic particles are present, while advanced lipoprotein testing can provide additional information about their characteristics.
Bottom Line
No single cholesterol number tells the entire story.
Triglycerides and HDL provide useful information about metabolic health. LDL cholesterol measures the cholesterol carried within LDL particles. ApoB provides information about the number of atherogenic particles, while advanced lipoprotein testing can provide additional information about LDL particle number and size.
Looking at these measurements together can provide a more complete picture than looking at LDL cholesterol alone.
For a broader discussion of cholesterol testing and cardiovascular risk, see Cholesterol & Cardiovascular Risk.
Learn More
Cholesterol Results Explained: Beyond the LDL Number - 14 Minutes
Cardiologist Dr. Bret Scher explains triglycerides, HDL, and other markers that can help put LDL cholesterol into context.
Ronald Krauss — Why Your LDL Score Doesn't Tell the Whole Story - 57 Minutes
Dr. Ronald Krauss discusses small, dense LDL, ApoB, triglycerides, and advanced lipid testing.
William Davis — The Nasty Little Monster Called Small Dense LDL Particles - 13 Minutes
Dr. William Davis explains why he considers small LDL particles particularly important and discusses their relationship to triglycerides, diet, and metabolic health.
Why You Should NOT Measure Apoprotein B – 13 Minutes
Dr. William Davis explains why he believes ApoB, although useful for estimating the number of atherogenic particles, provides less information than advanced lipoprotein testing that identifies small LDL particles and other features of metabolic health.
What Happens When You Keep Triglycerides 60 mg/dL or Less? - 13 Minutes
Dr. Davis explains why he recommends keeping triglycerides around 60 mg/dL or lower and how he believes this affects small LDL particles and metabolic health.