cholesterol

Cholesterol is a waxy fat-like substance your body genuinely needs — it builds cell membranes, makes hormones and vitamin D, and helps digest food. The problem is one of quantity and traffic control: in excess, and carried by the wrong particles, the same molecule that keeps cells working can help clog the arteries that feed the heart.

Because fat does not dissolve in blood, cholesterol rides inside protein packages called lipoproteins. LDL (low-density lipoprotein) ferries cholesterol out to tissues and, in excess, deposits it in artery walls — earning its nickname of bad cholesterol. HDL (high-density lipoprotein) carries cholesterol back to the liver for disposal and is broadly protective. Your liver makes most of your cholesterol, so blood levels reflect genetics and metabolism more than diet alone.

A balanced view helps: cholesterol is not a poison to be eliminated but a vital molecule to be kept in healthy range and well distributed. What matters for the heart is less the single total number than how much harmful LDL is circulating and the person's overall risk.