Cholesterol is manufactured in the liver for normal body functions, including the production of hormones, bile acid, and vitamin D. Cholesterol is required to build and maintain cell membranes; it regulates membrane fluidity over a wide range of temperatures. Cholesterol is a building block in many important cell components especially the cell membrane and is the starting point for several hormones. About one third to one fourth of the total amount of cholesterol is HDL cholesterol.

HDL cholesterol is called the "good cholesterol" because HDL cholesterol particles prevent atherosclerosis by extracting cholesterol from the artery walls and disposing of them through the liver. LDL cholesterol is called "bad" cholesterol, because elevated levels of LDL cholesterol are associated with an increased risk of coronary heart disease. Of particular interest is the finding that a high ratio of triglycerides to HDL cholesterol is a powerful risk factor for a major cardiac event even when LDL cholesterol levels are normal. It is now clear that any food that lowers LDL cholesterol or raises HDL cholesterol is what we should be looking for.

Most cholesterol is LDL cholesterol, and this is the kind that's most likely to clog the blood vessels, keeping blood from flowing through the body the way it should. Some cholesterol is normally present in plasma (the liquid part of blood) attached to proteins (lipoproteins) that transport it and other fat molecules around the body. When too much cholesterol is present, plaque (a thick, hard deposit) mayform in the body's arteries narrowing the space for blood to flow to the heart. LDL cholesterol is more likely to clog blood vessels because it carries the cholesterol away from the liver into the bloodstream, where it can stick to the blood vessels.

Cholesterol is so important that the body produces its own cholesterol. Cholesterol in food and cholesterol in the blood are distinct entities, and they are often confused. You need some cholesterol to help your brain, skin, and other organs grow and do their jobs in the body. When you have too much cholesterol, it can be dangerous to your health.

Cholesterol levels naturally rise as men and women age. Many factors can contribute to high cholesterol, but the good news is there are things you can do to control them. Try to eat less saturated fat, limit the amount of trans fat, and limit cholesterol (check food labels if you're not sure how much of these particular foods contain). Instead of eggs, try just egg whites or cholesterol-free commercial egg substitutes.

Changing from an unhealthy diet to a healthy diet can reduce a cholesterol level. If you find your blood cholesterol level is too high you can generally reduce it by following the advice of a trained dietitian, which generally means eating less fat and more fibre, and especially soluble fibre. Major dietary sources of cholesterol include egg yolks, beef, poultry, and shrimp. Here are some helpful tips you can try:Eat a diet that contains many low-cholesterol foods: fruits, veggies, whole grains (like breads and cereals), legumes (beans), and fish.

Eating a lot of fats and not getting enough exercise can cause cholesterol levels to rise. It's also a good idea to get plenty of exercise to help control the amount of cholesterol in your blood and keep your heart and blood vessels healthy. Major health agencies such as the Centers for Disease Control and Prevention and the American College of Sports Medicine (ACSM) recommend that for good health and to reduce risk of chronic disease, adult Americans should participate in moderate-intensity aerobic (or cardio) exercise (such as brisk walking) for at least 30 minutes on 5 or more days of the week or vigorous-intensity cardio at least 3 days of the week.