Blood lipids (or blood fats) are lipids in the blood, either free or bound to other molecules. They are mostly transported in a protein capsule. The density of the lipids and type of protein determines the fate of the particle and its influence on metabolism. The concentration of blood lipids depends on entry and exit from the intestine and cells. Blood lipids are mainly fatty acids and cholesterol. Hyperlipidemia is the presence of abnormal levels of lipids. High proteins in the blood is a major risk factor for cardiovascular disease.