Low density lipoprotein (LDL) constitutes lipoproteins that measure between 18 and 25 nanometers in diameter. Their main function is to guarantee the transport of cholesterol in the bloodstream to supply the cells. Cholesterol is a lipid involved in forming cell walls. If there is excessive production, this lipid can cause fatty deposits in the arteries, or arterial plaque. It is worth noting that LDL are secreted by the liver from very low density lipoprotein (VLDL).