What Puts You at Risk for High Cholesterol?

A bad diet is a sure way to spike your triglyceride reading.

Blood cholesterol is a risk factor for coronary artery disease and heart attack, so reducing your risk of high cholesterol is a worthy goal. However, the next time you brag that your cholesterol is nice and low—or lament that your number is in the mid-200s—know this: "Your total cholesterol is a pretty meaningless number," says Maureen Mays, MD, a preventive cardiologist and lipid specialist at Oregon Health & Science University in Portland. "Not only does the general public not know this, some doctors don't either."

Here's why "the number" is so misleading. Total cholesterol is calculated by adding LDL (bad cholesterol), HDL (good cholesterol), and one-fifth of your triglyceride total. "We have been using this formula of adding a bad thing to a good thing and factoring in one-fifth of a bad thing, and it's not useful," Dr. Mays says.

That's one reason 50% of people who have a heart attack have normal cholesterol readings.

Effects of diet and exercise
A smarter way of looking at cholesterol risk is by component. LDL, or bad cholesterol, is very responsive to good nutrition and exercise. The target number is less than 100 mg/dL. It's not uncommon for LDL to swing up by 40% in response to a sedentary lifestyle and a diet high in saturated and other unhealthy fats, according to Dr. Mays.

It can also drop by up to 40% in response to a heart-healthy diet and regular exercise.

One in 500 people has an inherited risk of extremely high LDL and should be put on statins to control their risk of heart disease.