Definition: Low density lipoproteins are tiny containers in your blood stream made of fat and protein. These containers carry cholesterol from your liver to the rest of the body.
When your blood has too much LDL, the cholesterol may combine with other substances to form plaques on the walls of your arteries. The plaques narrows your arteries and reduces flexibility. This leads to a condition called atherosclerosis.
A high LDL level is a risk factor for cardiovascular disease, so it is often called bad cholesterol. HDL cholesterol is considered good cholesterol. Eating a diet high in saturated fats and trans-fats may increase your LDL levels.