Cholesterol is a sterol (lipid or fat) that the human body needs to function properly, but too much cholesterol in the blood is bad because it can cause heart disease and stroke, among other problems. The cholesterol tends to increase with age but usually causes no symptoms, only detected with a blood test. People with family history of overweight or consuming lots of high-fat meal are very likely to have high cholesterol levels. You can lower cholesterol by performing exercise and consumption of fruits and vegetables.