Cholesterol, coined from three words chole(bile), stera(solid), ol(alcohol), this name followed it's discovery in composition with bile acids found on the walls of gall bladder. Cholesterol is a sterol: possessing the steroid ring/nucleus (cyclopentanoperhydrophenanthrene ring) and alcohol group. Cholesterol is a compound lipid exclusively found in animals forming a major part in cell membranes, the plant analog is phytosterol sources include: Avocado, groundnuts, other nuts, vegetable oil,legumes and fruits. It competes with cholesterol for absorption spot at the level of the small intestines.
Sources of cholesterol
Endogenous source: cholesterol is produced by the body via a complex pathway especially, if the body's demand is high and low dietary source. Exogenous sources: Egg(yolk), cheese, butter, liver, sausage, pork, beef, Ham, chicken, ice cream, clams, crab, lobsters, shrimps etc. Daily cholesterol consumption should not exceed 300mg.
Cholesterol as a foe
Cholesterol exists in various forms in blood bound to plasma proteins known as lipoproteins, these forms include: chylomicrons (aid in cholesterol and fatty acids absorption from intestines), very low density lipoprotein cholesterol (VLDL), low density lipoprotein cholesterol ( LDL), intermediate density lipoprotein cholesterol (IDL), high density lipoprotein cholesterol ( HDL). LDL cholesterol has two subunits the small and large LDL, the small LDL is known as "the bad cholesterol" reason being that in large amount of it or accumulation of it on the inner layers of arteries becomes problematic preventing effective flow of blood(Atherosclerosis), this is implicated in conditions like coronary artery disease - heart attacks, hypertension. The accumulation can lead to formation of blood clots, which travels to arteries with smaller diameter and occlude them resulting in conditions like stroke, peripheral vascular diesease, coronary artery disease issues etc. LDL cholesterol also has a role to play in insulin resistance typically, in obese patient contributing to diabetes mellitus.
Cholesterol as a friend
HDL cholesterol is known as the good cholesterol it plays a role in moving cholesterol from circulation back to liver for excretion purposes and in reverse cholesterol transport to some Target organs who need cholesterol for synthesis of other important substances like hormones. The good aspects of cholesterol includes:
- Insulation of nerve fibers aiding efficient nerve conduction
- Serves as a precursor molecule for bile acids formation which are important in fat absorption.
- It's a precursor molecule in synthesis of steroid hormone: estrogen, progesterone, testosterone, aldosterone, cortisol etc
- Vitamin D is made from a cholesterol precusor molecule, 7-dehydrocholesterol following exposure to certain range in wavelength of ultraviolet Rays.
- To ensure semipermeability and intergrity of cellular membranes, cholesterol plays a modulation role to keep the fluidity nature intact.