If we have too much cholesterol, it starts building up in our arteries (the blood vessels that carry blood away from the heart. This is called hardening of the arteries, or atherosclerosis. It is the starting point for some heart and blood flow problems. The buildup can narrow the arteries, make it harder for blood to flow through them and lead to dangerous blood clots and inflammation that can cause heart attacks and strokes.

clog in blood vein
Picture 2. Atherosclerosis

There are two types of cholesterol: