A high blood cholesterol level, especially elevated low density lipoproteins (LDL), is considered to be a contributor to plaque building up in the arteries and impeded blood flow to the brain, kidneys, genitals, extremities, and heart. It is among the primary causes of heart disease, because cholesterol produces deposits in arteries. High cholesterol levels may also be implicated in gallstones, impotence, mental impairment, and high blood pressure.
Cholesterol is an essential part of every cell structure and is needed for proper brain and nerve function. It is also the basis for the manufacture of sex hormones. Cholesterol is manufactured in the liver and transported through the bloodstream to the sites where it is needed. It is a fatty substance and, because blood is mainly water, it has to latch on to molecules called lipoproteins to travel around successfully. Low density lipoproteins (LDLs) are the major transporters of cholesterol in the bloodstream and, because LDLs seem to encourage the deposit of cholesterol in the arteries, it is known as bad cholesterol. High density lipoproteins (HDLs), on the other hand, are to be considered good cholesterol because they carry unneeded cholesterol away from the cells and back to the liver, where it is broken down for removal from the body. If everything is functioning as it should, this system remains in balance. However, if there is to much cholesterol for the HDLs to pick up promptly, or if there are not enough HDLs to do the job, cholesterol can form plaque that sticks to artery walls and may eventually cause heart disease.
It is important to distinguish between serum cholesterol and dietary cholesterol. Serum cholesterol is the cholesterol in the bloodstream. Dietary cholesterol is cholesterol that is present in food. While eating foods high in dietary cholesterol can raise serum cholesterol, it is not the only source in serum cholesterol. Indeed, you would have some amount of serum cholesterol even if you never ate any food containing dietary cholesterol because the body produces its own cholesterol.
Cholesterol levels are greatly influenced by diet, but they are also affected by your genetic makeup. The consumption of foods high in cholesterol and or saturated fat increases cholesterol levels, while a vegetarian diet, regular exercise, and the nutrients niacin and vitamin c may lower cholesterol.
The National Cholesterol Education Program has set the safe level of total serum cholesterol including both LDL and HDL at 200 milligrams per deciliter of blood (mg/dl). A reading above 200 indicates an increased potential developing heart disease. A level of 200 to 239 is borderline, and levels over 240 are considered to indicate high risk. The normal HDL level for adult men in the United States is 45 to 50 mg/dl, and that for woman is 50 to 60 mg/dl. It is suggested that higher HDL levels, such as 70 or 80 mg/dl, may protect against heart disease. An HDL level under 35 mg/dl is considered risky. So if you have a cholesterol reading of 200, with HDL at 80 and LDL at 20, you are considered at low risk of heart disease. On the other hand, even if you have a total cholesterol level well under 200, if your HDL level is under 35, you will still be considered at increased risk of developing cardiovascular disease. In other words, as your HDL decreases, your potential for heart problems intensifies, even if your total is on the low side.