Cholesterol is a waxy, fat-like substance occurring naturally in the body cells. Cholesterol is an essential component of the body because it is used used for producing cell membranes and some hormones, bile acid and vitamin D. Cholesterol is also required for some other vital functions of the body. But too much cholesterol in the blood is not desirable as it will be deposited in the arteries that causes coronary heart disease and stroke. It is very important to get the cholesterol levels checked on a regular basis.
Cholesterol and other fats can not dissolve in the blood. They are carried onto the blood by lipoproteins.
The two main type of lipoproteins are LDL and HDL.
- Low-density lipoprotein (LDL). It is the main cholesterol carrier and transports cholesterol from the liver to the cells where it is needed. LDL is known as “bad cholesterol,” since it can stick together to form plaque deposits on the walls of our blood vessels, leading to atherosclerosis.Too much LDL cholesterol (160 mg/dL and above) in the blood is a risk factor for heart disease.
- High-density lipoprotein (HDL). It is responsible to transport cholesterol away from the cells and back to the liver, where it is either broken down or excreted as a waste product. Therefore, it is known as as ‘good cholesterol’, and higher levels are better. Low HDL levels (less than 40 mg/dL in men; less than 50 mg/dL in women) indicates a greater risk for heart disease.
Triglycerides are not cholesterol but another type of fat floating in the blood. A high level of triglycerides increases the risk of cardiovascular problems. It should be kept at a level of less than 150 mg/dL.
Total cholesterol is the sum of LDL, HDL and 20% Triglycerides. We can calculate cardiac risk rask ratio as given below.
cardiac risk ratio = total cholesterol divided by HDL cholesterol
- It is important to note that a cardiac risk ratio greater than 7 is considered a warning.
Sources of Cholesterol
Based on the source, the cholesterol can be endogenous or exogenous. Endogenous cholesterol refers to cholesterol that is made inside the body by liver and other cells. Exogenous cholesterol is the cholesterol that comes from outside of the body. It enters into our body through the food we eat. Cholesterol is only found in animal products mainly meat, poultry, fish, pork, and dairy products. Organ meats, such as liver, are especially high in cholesterol content, while foods of plant origin contain no cholesterol.
According to World Health Organization estimates, almost 20% of all strokes and over 50% of all heart attacks can be linked to high cholesterol.