Cholesterol is a waxy, fat-like substance made naturally by your body. You also can get cholesterol from the foods you eat. If you have too much cholesterol in your blood, you may be at risk for heart disease or stroke.

Those are some key facts you should know about cholesterol, but you should also be aware of some common myths, along with the important truths:

Myth: As long as you eat a healthy diet and exercise, your cholesterol levels will be fine.

Truth: Diet and physical activity are big players when it comes to healthy cholesterol levels. Other factors can play a role in whether you're at risk for unhealthy cholesterol levels. For example, blood levels of LDL (the bad) cholesterol tend to rise with age. Smoking lowers levels of HDL (the good) cholesterol and raises LDL cholesterol. Heredity also can play a role in your cholesterol levels.

Myth: You don't need to check your cholesterol levels unless you have symptoms.

Truth: High cholesterol doesn't have any symptoms. The only way to learn your cholesterol levels is to have a blood test.

Myth: Children aren't at risk for high cholesterol.

Truth: High cholesterol can be inherited. Children and teens who have a condition called familial hypercholesterolemia are at very high risk for heart disease. Kids and adolescents should have their cholesterol tested if they have:

• A parent or grandparent who had heart disease, a heart attack or sudden cardiac death before age 55.

• A parent who has a history of high total cholesterol levels (240 mg/dL or higher).

Myth: You don't have to be concerned about cholesterol if you're not overweight.

Truth: It's true that people who are overweight are at increased risk of having high cholesterol. Thin people can have problems with their cholesterol levels too if they eat too much saturated and trans fat—both of which can raise the level of LDL cholesterol in the blood.