Harvard Health Letter

Ask the doctor: Is my LDL cholesterol too low?

Q. I'm 80, and I exercise or bike for an hour and a half almost every day and eat a healthy diet. I recently had a blood lipid assessment, and my HDL was 70 and my LDL was 42. But my internist wrote me saying that my LDL was too low and that I should cut my dose of atorvastatin from 40 mg to 20 mg a day. I also take 2,000 mg of niacin daily. Is there general agreement that one's LDL should not go below a certain point? Is mine too low?

A. First, let me say that you are doing great. Most people even half your age aren't as physically active, and your cholesterol levels are impressive. An HDL level of 70 milligrams per deciliter (mg/dL) is above the 60 mg/dL threshold where the "good" cholesterol seems to afford some protection against heart disease and stroke. Your LDL of 42 mg/dL is comfortably in the optimal range for "bad" cholesterol, which is 100 mg/dL or less.

There really isn't evidence of harm from driving your LDL too low. In the past, some scientists worried that extremely low LDL levels could result in blood vessel ruptures and perhaps increase the risk of getting certain types of cancer. Those concerns have faded after neither occurred in large clinical trials that involved reducing people's LDL to very low levels.

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