Your body requires fat and cholestrol to maintain good health. During infancy and childhood, fat is essential for normal brain development; throughout life, it is essential to provide energy and support growth. Cholestrol is used to build the walls of cells throughout the body and to manufacture essential substances like hormones and vitamin D. So it is important to have some fat and cholestrol available in your body at all times. But you can get too much of a good thing, and when the amount of fat and cholestrol you consume becomes excessive, health problems can begin to appear.

It is important to recognize that although fat and cholestrol are essential for good health, you do not always need to get these substances from your diet. After two years of age, in fact, the body requires only small amounts of dietary fat, and needs no dietary cholestrol at all, as the liver is capable of manufacturing whatever is necessary. In spite of this, most of us consume very large amounts of both fat and cholestrol – in many cases, enough to increase our health risks significantly. Excessive fat intake is an important causative factor in obesity, high blood pressure, coronary artery disease, and colon cancer. Excessive dietary cholestrol increases the risk of heart attack and stroke. How do these substances contribute to these life-threatening disorders? To understand this it is necessary to learn a little more about the actions of fat and cholestrol within the body.

Understanding cholestrol

Cholestrol is a white, waxy, fatty substance that is produced by the liver and is also present in foods of animal origin, including beef, poultry, fish, cheese, eggs, and dairy products. In general, the more cholestrol you put into your body by eating such foods, the higher hte level of cholestrol in your blood will be. But dietary cholestrol is not the only thing that determines your blood cholestrol level. Dietary fat – especially saturated fat – and the cholestrol that your liver manufactures on its own also play important roles.

Pure cholestrol cannot mix with or dissolve in solutions like water and blood, so it is combined in the liver with other substances – fats and proteins – to form particles that are capable of moving through the bloodstream. These particles, called lipoproteins, carry cholestrol from the liver to the parts of the body where its is needed, and then bring it back again for removal from the body. A distinction has been made between two principal types of lipoproteins: the low-density lipoproteins (called LDLs, or LDL cholestrol) and the high-density lipoproteins (called (HDLs, or HDL cholestrol). The levels of each of these forms of cholestrol in the blood can be measured separately. Together, they make up most of your “total blood cholestrol,” or “total cholestrol.”

Low-Density Lipoproteins (LDLs)

Low-density lipoproteins contain mostly cholestrol and protein. These LDLs are removed from the bloodstream by cells throughout the body, and then are broken down into their original elements, which are used for essential bodily functions. However, some people’s systems remove LDLs more slowly than others, causing the level of LDLs – and thus cholestrol – to build up in their blood. This tendency to remove LDLs and cholestrol quickly or slowly is inherited.

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