First, let me congratulate you on your excellent HDL ("good") cholesterol level. A HDL (high-density lipoprotein) of 78 is a very good indication that you're at low risk of heart disease and there is absolutely no need to lower it. As a matter of fact, recent studies on cholesterol and heart disease have suggested that each increase of 4 mg/dl in the HDL level results in a 10 percent decrease in risk of adverse coronary events. Let me explain what HDL is and why the higher it is, the better it is for you.
HDL is called "good" cholesterol because in this form cholesterol travels away from the arteries and back to the liver for eventual elimination from the body. In contrast, LDL ("bad") cholesterol combines with other substances that can build up in the walls of arteries to form "plaque." Over time, this plaque damages arterial walls, causing them to narrow and harden. Also, the rough surface of plaque can provide a site for blood to clot, sometimes completely blocking an artery.
According to new guidelines from the National Cholesterol Education Program, HDL levels below 40 mg/dl are classified as low and are associated with a higher risk of coronary heart disease. HDL levels of 60 mg/dl or above are classified as high and considered protective against heart disease. So you have nothing to worry about.
HDL and LDL levels are influenced by heredity, diet, weight, exercise, age, gender, alcohol consumption, and stress. Your HDL level of 78 would be the envy of those people who are trying to increase theirs via weight loss and exercise. I have no idea why you were told that your HDL should be 59 - that's a very healthy level but 78 is even better!
Andrew Weil, M.D.