What is cholesterol and why does it matter?
Cholesterol is a type of fat (lipid) that is found in your blood and every cell of your body. It is important because high levels of cholesterol in your blood increase your risk of developing coronary heart disease (CHD).
Note: CHD is one of the most common causes of death and disability in Europe, North America, and Australia. Where Does Cholesterol come from?
The cholesterol in your body comes from two sources:
1. Your diet
2. What you make yourself
Typically around seven times more cholesterol is made in your body from dietary saturated fats (animal and dairy fat) than is absorbed as cholesterol from your food.
Most cholesterol is not an essential part of your diet solely because your liver can provide all the cholesterol that your body needs.
Dietary cholesterol is absorbed from your small intestines and travels in the blood to your liver, where it mixes with cholesterol produced in the liver itself.
Cholesterol from these two sources then travels to other body tissues where it is needed to make cell membranes, and to act as a building block for making steroid hormones or vitamin D.
Cholesterol Transport Around The Body
As cholesterol does not dissolve in blood serum, which is mostly water, it is first stabilized for transportation. This is done by packaging it in particles called lipoproteins.
The two types of proteins that are important for cholesterol transport are low-density lipoprotein (LDL) and High-density lipoprotein (HDL).
Roles of LDL and HDL
Low-Density Lipoproteins: Most of the cholesterol in blood is in LDL particles. The major purpose of LDL is to deliver cholesterol produced in the liver to body tissues. It performs this function by binding to the LDL receptors in tissue cells through the help of a specialized protein called Apoprotein B (or ApoB) located on its surface. Although cells can also manufacture cholesterol when LDL particles cannot get into cells.
Cholesterol is continually removed from cells in high density lipoproteins (HDLs), which take cholesterol from cells to the liver; this then excretes it in bile. Thus, as well as producing cholesterol, the liver can also remove cholesterol from the blood. Excess cholesterol from cells can be removed from the body by this mechanism.
The importance of cholesterol
1. Cell structures: Cholesterol occurs in every cell of your body and forms a vital part of the membrane that surrounds each cell, preventing cells from being too leaky.
2. Hormones: Cholesterol is also the basis for many hormones essential for the regulation of growth and the way your body works on a day to day basis. Hormones made using cholesterol include the following oestrogens and progestogens, testosterone, cortisol, aldosterone and the active form of vitamin D (1,25 dihydrocholecalciferol).
3. Digestion: Bile acids are also made from cholesterol in the liver and act like detergents in your gut, dissolving fat from your food.This is necessary for the normal digestion and absorption of lipids and fat-soluble vitamins (A, D, E, and K).if bile acids don’t reach your gut from the gallbladder, where they are stored, fat is not digested properly- the result is diarrhea, and the fat is lost in pale, very small stools.
Although it is clear that too much cholesterol can cause heart disease, it would be impossible to survive without it.
To be Continued….
Compiled by Pharm Odebiyi Seye
Vanguard Pharmacy Limited