Our body does need cholesterol to make bile salts, hormones and vitamin D. It is mainly produced by our liver. Cholesterol will build up on the artery walls when the level of cholesterol in the blood is too high. There are 2 main types of blood cholesterol: LDL (the “Bad” cholesterol) and HDL (the “Good” cholesterol).
High amounts of the bad LDL will deposit cholesterol on the artery walls forming plaques. More and more plaques will narrow the arteries lumen and may eventually block blood flow. Therefore LDL is considered the “Bad” cholesterol. Saturated fats and trans fatty acids are the most important factors that raise blood cholesterol, not dietary cholesterol! Monounsaturated fats and polyunsaturated fats found in nuts and fish for instance, can lower the LDL level. In addition, soluble fiber found in fruits, oats, barley and legumes can also lower LDL.
The good HDL, on the other hand, takes excess cholesterol away and carries it back to the liver to be excreted. It can also remove some of the cholesterol already attached to the artery walls. Therefore HDL is considered the “Good” cholesterol