With the increased emphasis on low-cholesterol diets and lowering your cholesterol levels, it's easy to forget that cholesterol is a necessary substance for your body. In fact, the role of cholesterol in a diet is an important one, and though it puts you at risk for consuming too much cholesterol, a certain amount of cholesterol is necessary for good health.
Identification
Cholesterol is a thick, waxy substance that looks like solid fat. Your body makes cholesterol, and you also get cholesterol in your diet whenever you eat food that comes from animal sources, including meat, eggs and dairy products. Food that doesn't come from animals, including fruits, vegetables and grains, doesn't contain cholesterol unless it's cooked with a food, such as butter, that does contain cholesterol. Every cell in your body contains some cholesterol.
Types
Cholesterol is oily and blood is mostly water, so in order for cholesterol to move through the bloodstream, it has to be encased in a protein coat called a lipoprotein. The contents of the lipoprotein shell determine the type of cholesterol. Low-density lipoprotein (or LDL) has a high ratio of fat to protein and is the most common form of cholesterol in the body. People sometimes refer to LDL as "bad cholesterol" because it leaves cholesterol deposits in arteries where it can increase your risk for heart disease. High density lipoprotein (or HDL) has a higher ratio of protein to fat and is called "good cholesterol" because of its ability to collect cholesterol deposits from the arteries and transfer them to liver for export from the body. LDL and HDL are the components most people think of when they talk about cholesterol, but there are other types of cholesterol, too, including chylomicrons, which are created from digested fat, and very low density lipoprotein (VLDL), which transports the triglycerides through the body.
Function
According to the Yale University School of Medicine Heart Book, cholesterol performs three major functions in your body. First, it plays a role in the production of certain hormones, including sex hormones. Second, it helps the liver make bile acid, which your body requires to digest fat. And third, it plays a significant part in cellular structure, making it possible for the body to build and repair its many cells.
Considerations
High levels of LDL cholesterol have been associated with heart disease and related health problems, so the American Heart Association recommends limiting your cholesterol intake to 300mg per day. This means reducing the amount of animal-derived foods, foods with saturated fat and foods with trans fats that you eat. High levels of HDL, on the other hand, may actually reduce your risk of heart disease, so be sure to include plenty of HDL-raising foods such as nuts, soluble fiber and olive oil in your diet.
Expert Insight
The Yale University School of Medicine Heart Book recommends maintaining a diet high in HDL cholesterol and low in LDL cholesterol to get the benefits of cholesterol while reducing its risks. It also suggests adding regular exercise to your daily routine as a way to improve cholesterol levels.
