VLDL (very low-density lipoprotein) lipid subfractions characterise the size and distribution of VLDL particles produced by the liver. VLDL particles carry triglycerides from the liver to peripheral tissues for energy use or fat storage. Like LDL, VLDL is not a single particle type — it exists as large, medium, and small particles with different metabolic fates and atherogenic potential.
Large VLDL particles are produced in excess under conditions of high caloric intake, high refined carbohydrate consumption, and insulin resistance. Elevated large VLDL drives down HDL and promotes the formation of small dense LDL — the key mechanism of atherogenic dyslipidaemia. VLDL subfraction testing quantifies this upstream driver and provides mechanistic insight into why an individual's LDL particle profile may be shifting toward a more dangerous pattern.
FAQs
What is the connection between VLDL and small dense LDL?
Large VLDL particles donate triglycerides to LDL via CETP (cholesteryl ester transfer protein) in exchange for cholesterol. This triglyceride-enriched LDL is then hydrolysed by hepatic lipase into smaller, denser LDL particles — the atherogenic small dense LDL phenotype.
Is VLDL the same as triglycerides?
Not exactly. Standard triglycerides measure all triglycerides across all lipoprotein classes. VLDL carries the largest proportion of circulating triglycerides. VLDL subfractions characterise which particle sizes are carrying the triglyceride burden.
Can VLDL be too low?
Very low VLDL (and thus very low triglycerides) is seen with very low fat intake, malnutrition, or rare lipoprotein disorders like abetalipoproteinaemia. It is rarely clinically problematic.
Are VLDL subfractions in standard panels?
No. VLDL subfraction analysis requires specialised advanced lipid testing, not part of standard lipid panels.
