Cholesterol | Hyperlipidemia | Hypercholesterolemia

Cholesterol is a waxy steroidal metabolite mostly found in the cell membranes and it is transported in the blood plasma of all mammals. It is an essential structural component of cell membranes in mammals. Cholesterol is required to establish proper membrane permeability and fluidity. Additionally, it is utilized for the manufacturing of bile acids, steroid hormones, and several fat-soluble vitamins.

Cholesterol Functions
Cholesterol is needed to build and maintain membranes; it maintains membrane fluidity over the range of physiological temperatures. In the liver, cholesterol is converted into bile, which is then stored in the gallbladder. Bile contains bile salts, which can solubilize fats in the digestive tract and aid in absorption of fat molecules as well as the fat-soluble vitamins such as Vitamin A, D, E, and K.

Cholesterol is needed as a precursor molecule for the synthesis of Vitamin D and many steroidal hormones, such as adrenal gland hormones cortisol and aldosterone as well as the sex hormones progesterone, estrogens, and testosterone, and their derivatives. But High cholesterol is harmful to the health develops cholesterol deposits and causes heart attack.

Cholesterol Sources
Major dietary sources of cholesterol can include - cheese, egg yolks, beef, pork, poultry, and shrimp. However, plant products such as flax seeds and peanuts contain phystosterols look similar to cholesterol, but they are suggested to help lower serum cholesterol levels.

Fat metabolism
The lipid transport can be divided into the exogenous pathway, which refers to the metabolism of intestinally derived lipoproteins, and the endogenous pathway, which refers to hepatic-derived lipoproteins.

Cholesterol Synthesis, Regulation & Recycling
About 20 to 25% of total daily cholesterol production occurs in the liver; other sites of high synthesis rates include the intestines, adrenal glands, and reproductive organs.

Biosynthesis of cholesterol is directly maintained by the cholesterol levels present, though the homeostatic mechanisms involved are only partly understood. A higher intake of cholesterol from food leads to decreased endogenous production, whereas lower cholesterol intake from food has the opposite effect.

Liver oxidizes cholesterol into a variety of bile acids and it is excreted from the liver into the bile. Almost 95% of the bile acids are reabsorbed by the intestines and the balance lost in the feces. The excretion and re-absorption cycle of bile acids makes the basis for the entero-hepatic circulation which is needed for the proper digestion and absorption of dietary fats.

HDL & LDL (good and bad cholesterol)

• Low density lipoprotein (LDL bad cholesterol) is a type of lipoprotein that transports cholesterol and triglycerides from the liver to peripheral tissues.


• High density lipoprotein (HDL good cholesterol) is a type of lipoprotein that brings back cholesterol from the cells to the liver.