Cholesterol is an organic chemical substance and is a steroid of fat. High levels of this steroid fat can cause real problems with humans leading to heart and circularity problems as the fat builds up layers in vital veins thereby restricting blood flow to vital organs such as the heart and can n some cases cause heart failure. On the other hand humans require this essential and important steroid fat to keep us healthy, as it responsible for creating and maintaining membranes within our bodies, the trick is to get the intake balance correct. Cholesterol was first discovered in 1769 in the gallstones.