Cholesterol is a substance found in your body. It is needed in small amounts for the normal functioning of the body and is essential for life. It makes up part of the cell membrane of all the cells in your body. Cholesterol is a soft, waxy substance that does not dissolve in blood. It is delivered to the cells in particles called lipoproteins. There are two types of cholesterol: low density lipoprotein (LDL) and high density lipoprotein (HDL). They both have different functions and affect you in different ways.
Sources of Cholesterol
Cholesterol is found in your body. It comes from the food you eat and is manufactured in your liver as well. Your blood levels of cholesterol may also depend on your genetic makeup. Some people tend to make more cholesterol than others and therefore have high blood cholesterol levels. High blood cholesterol levels can lead to clogging up of your arteries, and this condition may put you at risk for heart disease, such as a heart attack.
Functions
Cholesterol is used in the production of different steroid hormones. They are important in the synthesis of hormones that are neccessary for growth, development and reproduction such as cortisol, cortisone, estrogen, progesterone and testosterone. Vitamin D production is also dependent on cholesterol. Bile acids play a part in the absorption of nutrients from food in your digestive tract and has cholesterol as one of its components.
Low Density Lipoprotein/LDL
Low density lipoprotein or LDL increases your risk for heart disease and, because of this, it is often referred to as "bad cholesterol." LDL is more abundant than HDL cholesterol in your body. It travels through your blood to all the cells in your body and in the process may build up on the walls of your arteries. This can lead to plaque formation or atherosclerosis. Thick layers of plaque can reduce blood flow to your heart and cause angina; if blood flow is totally cut off by plaque, a heart attack develops.
High Density Lipoproteins HDL
High density lipoproteins unlike LDL reduces your risk for heart disease and is referred to as "good cholesterol" because of this. Like LDL, it is transported in your blood and makes up about a third to a quarter of the cholesterol in your body. While LDL transports cholesterol to the cells in your body, HDL trasports cholesterol from different parts of your body to your liver, where they are disposed of. This causes a reduction in your cholesterol blood levels. They also remove LDL from the walls of your arteries and slow the growth of plaque. HDL has to be present in your body and in the right amount to effectively reduce your risk for heart disease.
Recommendations
The American Heart Association suggests that a total blood cholesterol level of 200mg/dl or lower is desirable for maintaining a low risk of heart disease, in the absence of other risk factors for heart disease. It goes on to state that a HDL level of 60mg/dl or higher gives some protection against heart disease while 100mg/dl or less of LDL is optimal for heart disease risk reduction.
