Cholesterol is a waxy, fat-like substance that is found in all cells of the body. Your body needs some cholesterol to work the right way and makes all the cholesterol you need.
Blood is watery and cholesterol is fatty. Just like oil and water, the two do not mix. So, in order to travel in the bloodstream, cholesterol is carried in small packages called lipoproteins (lip-o-PRO-teens).
Two kinds of lipoproteins carry cholesterol throughout your body. It is important to have healthy levels of both:

Low-density lipoproteins (LDL) cholesterol is sometimes called "bad" cholesterol. High LDL cholesterol leads to a buildup of cholesterol in the arteries. The higher the LDL level in your blood, the greater chance you have for getting heart disease.
(Arteries are blood vessels that carry blood from your heart to your body.)

high-density lipoproteins (HDL) cholesterol is sometimes called "good" cholesterol. HDL carries cholesterol from other parts of your body back to your liver. The liver removes the cholesterol from your body. The higher your HDL cholesterol level, the lower your chance of getting heart disease.

High Blood Cholesterol
Too much cholesterol in your blood can build up in the walls of your arteries. This buildup of cholesterol is called plaque (PLACK). Over time, plaque can cause narrowing of the arteries. This is called atherosclerosis or "hardening of the arteries." Special arteries, called coronary arteries, bring blood to the heart. Narrowing of your coronary arteries due to plaque can stop or slow down the flow of blood to your heart. When the arteries narrow, the amount of oxygen-carrying blood is decreased. This is called coronary artery disease (CAD). Large plaque areas can lead to chest pain called angina. Angina happens when the heart does not receive enough blood and the oxygen it carries with it. Angina is a common sign of CAD.
Some plaques have a thin covering and burst (rupture), releasing fat and cholesterol into the bloodstream. The release of fat and cholesterol may cause your blood to clot. A clot can block the flow of blood. This blockage can cause angina or a heart attack. Lowering your cholesterol level decreases your chance for having a plaque burst and the chance of a heart attack. Lowering cholesterol may also slow down, reduce, or even stop plaque from building up.

What causes High Blood Cholesterol ?
Certain foods have types of fat that raise your cholesterol level.
• Saturated fat raises your LDL cholesterol level more than anything else in your diet.
• Trans fatty acids (trans fats) are made when vegetable oil is "hydrogenated" to harden it. Trans fatty acids also raise cholesterol levels.
• Cholesterol is found in foods that come from animal sources, for example, egg yolks, meat, and cheese.

Cholesterol content of various food

Food Name Cholesterol mg per 100 grams
Two Egg yolks 360 mg
Clarified butter; Ghee 256 mg
Butter 250 mg
Cream 137 mg
Ice cream 47 mg
Evaporated milk 29 mg
Skimmed Milk 4 mg
Egg White 0 mg
Fruits 0 mg
Nuts  0 mg
Grains 0 mg

Daily Cholesterol Limit
Health guidelines advise that total blood cholesterol levels be kept below 200 mg/dL, and that LDL cholesterol be kept below 100 mg/dL.
On a day to day basis, this means you should limit your average cholesterol intake to less than 300 milligrams per day. But, if you have been diagnosed with heart disease, this should be reduced further to an intake of less than 200 milligrams per day. -

“It is a scientific fact that your body will not absorb cholesterol if you take it from someone else's plate.” ― Dave Barry