The best vitamin d comes naturally from the sun and specifically when UV-B radiation hits cholesterol in the blood in the skin turning it into vitamin D3. When you get more D3 than the body needs it starts accumulating and being stored in the liver. This tells the liver to stop producing cholesterol. Too much cholesterol in the blood is simply your body telling you that you are not getting enough sunshine. When you get your cholesterol checked do so in late summer to late fall. Cholesterol levels will be lower during that time than at any other in the year. The darker your skin the more sunshine you need to produce the necessary quantity of D3.