Low-density lipoprotein (LDL) is one of the five major groups of lipoproteins, which in order of size, largest to smallest, are chylomicrons, VLDL, IDL, LDL, and HDL, that enable transport of multiple different fat molecules, including cholesterol, within the water around cells and within the water-based bloodstream. Studies have shown that higher levels of type-B LDL particles (as opposed to type-A LDL particles) are associated with health problems, including cardiovascular disease.
Low-density lipoprotein (LDL) is called sometimes the bad cholesterol because in large quantities can build up plaque in the walls of the arteries. This, in turn, increases the risk of a heart attack or stroke. There is no bad cholesterol, LDL is critical for our health, and we make most of the cholesterol needed for a healthy life, (about 80% of the total cholesterol is produced by our liver and intestines).
From a coffee drinking perspective, it has been shown that unfiltered coffee, containing all of the coffee oils, can increase the production of cholesterol. The two substances responsible for increasing the cholesterol levels are cafestol and kahweol. Filtering coffee changes its taste profile. Some coffee lovers prefer the unfiltered coffee.