When you hear the word “cholesterol,” many people associate it with a negative health problem. True, elevated low-density (LDL) cholesterol levels can contribute to heart disease and poor circulation. But healthy high-density (HDL) cholesterol is responsible for providing cell membrane structure and insulating nerve cells in your brain. Be sure to have your doctor check your “good” HDL cholesterol and “bad” LDL cholesterol levels to get a true indication of your blood test reading.