Differentiate between LDL and HDL and explain why elevated LDL concentrations in the blood are a sign of high heart attack risk

Answer 1

Low-density lipoproteins (LDL) are lipoproteins that transport lipids from the liver to other tissues such as muscle and fat; they contain a large proportion of cholesterol. High-density lipoproteins (HDL) pick up cholesterol from body cells and carry it away to the liver for disposal. Both LDL and HDL carry cholesterol, but high blood LDL concentrations warn of an increased risk of heart attack, whereas low HDL concentrations are associated with a greater risk. Thus, some people refer to LDL as "bad" cholesterol and HDL as "good" cholesterol—yet they carry the same kind of cholesterol. The key difference to health between LDL and HDL lies in the proportions of lipids they contain and the tasks they perform, not in the type of cholesterol they carry. When LDL cholesterol is too high, it contributes to lipid buildup in tissues, particularly in the linings of the arteries, that can trigger inflammation and lead to heart disease; HDL cholesterol opposes these effects, and when HDL in the blood drops below the recommended level, heart disease risks rise in response.