Which statement about IDL is true?

• A. IDL are formed when VLDL loses fatty acids, and some are cleared by the liver while others become LDLs
• B. IDL is a type of HDL
• C. IDL is produced in the intestine
• D. IDL carries cholesterol to tissues

Answer: (A)

IDL is formed when VLDL loses triglycerides in the bloodstream via lipoprotein lipase, shrinking into an intermediate-density particle. From there, pathways diverge: some IDL particles are cleared by the liver as remnants (often via apoE-mediated uptake), while others are acted on by hepatic lipase, which removes more triglycerides and converts IDL into LDL. This sequence matches the statement and is why it’s true.

IDL is not HDL, and it isn’t produced in the intestine (that’s where chylomicrons originate). While IDL does carry cholesterol, its primary fate is either hepatic clearance or conversion to LDL, which then delivers cholesterol to tissues.