Cholesterol appears in the fat deposits that form in the linings of the arteries, causing these vessels to become less elastic. The role of blood-cholesterol level in forming these deposits is unknown. This process, known as atherosclerosis, takes place gradually, in any artery of the body, beginning at any time from childhood on. When the fatty deposits in the arteries are heavy and irregular, they are known as plaques.
These plaques can restrict or even stop the flow of blood through the arteries or can cause rough spots that may break loose and create blood clots. When this occurs in one of the major blood vessels of the heart or brain, it causes a coronary or a stroke.
Medical experts stress that diet alone does not create a high risk of heart disease. Your heredity, physical activity, smoking habits, body weight, and even your personality may all play a part. New discoveries are continually changing the medical community’s views of cholesterol and heart disease. Most recently, two types of cholesterol-carrying lipoproteins have been linked to protection against or promotion of the disease process.
Though both of these lipoproteins contain cholesterol, the “protective” higher density ones (HDL) are found in greater amounts in people who exercise, drink only moderately, and do not smoke; while the “promoting” lower density ones (LDL) are more prevalent in obese people, smokers, and sedentary people. This research has not proven a connection between diet and these lipoproteins, but it does provide further evidence that there is a wide variety in the way people do and do not respond to diet, in the composition of their blood, and in their tendency to develop heart disease.