VLDL is made in the liver in response to a high-carbohydrate meal. The liver converts the extra carbohydrates into fat (triglycerides) and puts them into VLDLs to be transported to fat cells and muscle within the body. The liver also puts some cholesterol into the VLDL. A VLDL particle is rather large, carrying a lot of triglycerides relative to the amount of cholesterol.
Once a VLDL delivers its triglycerides to fat cells or muscle, it is called an intermediate density lipoprotein (IDL). This IDL can return to the liver with its cholesterol so that the liver can repackage it to use it later or simply get rid of it. But in most cases, the IDLs remain in the blood and go through another transformation where they lose most of their remaining triglycerides. At this point, the IDLs are almost all cholesterol and are now known as LDL. About three-quarters of total cholesterol in the blood is contained within LDL particles.
Several conditions are known to increase VLDL levels, including:
- Cushing's syndrome
- Genetic conditions
- Nephrotic syndrome
- Acute hepatitis
- Certain cancers, including lymphoma and myeloma.
Alcohol and birth control pills can also increase VLDL.
VLDL is thought to play a role in atherosclerosis, which is narrowing and hardening of the arteries.
Cholesterol research studies have shown that VLDL can be lowered through: