Dietary Cholesterol & Metabolism

Dietary cholesterol is an essential part of healthy eating and normal body function. Every cell in the human body requires a certain amount of this material to carry out the process of metabolism. While the body can synthesize its own cholesterol, it still needs a certain amount of it to come through daily food intake.

Identification

Cholesterol is a fatty substance manufactured by the liver as well as metabolized from dietary intake. The needs of the body determine how much will be manufactured by the liver. Cholesterol is a base material, so the body can't use it for energy metabolism needs; however, it does serve multiple purposes. One of its most essential roles is supporting cell membrane structure and function. It also is a required material for the manufacturing of steroids and bile salts.

Cell Metabolism

The body's metabolism processes are made up of metabolic pathways that regulate digestion on a cellular level. Chemical reactions triggered by enzymes determine when carbohydrates, proteins and sugars are metabolized. Cell membranes play a vital role in transporting oxygen and nutrients in and out of the cell. A number of metabolic pathways reside within each cell and work to coordinate how the cell uses nutrients. Cell membranes rely on their cholesterol content to maintain their density and their ability to allow nutrients to move through.

Blood Cholesterols

Dietary cholesterols move through the bloodstream along with other food nutrients. Special carriers called lipoproteins are responsible for transporting cholesterol into cell structures. Lipoproteins come in two forms--high density (HDL) and low density (LDL). Lipoproteins are protein molecules specifically designed to transport cholesterol materials into the cells. A routine blood test is used to identify the number of LDL vs. HDL in the blood.

Liver Functions

In addition to manufacturing cholesterol, the liver is responsible for eliminating fats and excess cholesterols from the body. It does this by converting these materials into bile acids, which are then eliminated as waste. Lipoprotein carriers assist with delivering a portion of the excess blood cholesterol to the liver. Metabolic pathways coordinate these processes by means of enzyme reactions. These reactions are triggered when a certain amount of fats and cholesterols are present in the bloodstream.

Effects

After a certain point, the liver can handle only so much cholesterol. When dietary intake exceeds the needs of the body, damage to the blood vessels can result. Once the body's cells have reached their limit, any excess cholesterol remains in the bloodstream. LDL lipoproteins are left to carry excess amounts through the bloodstream and will leave deposits of cholesterol along blood vessel walls. When this happens, blood flow is impaired and vessel walls become damaged.

References

• Cholesterol Metabolism
• Cholesterol

Resources

• Metabolism & Biochemistry
• Intracellular Cholesterol Metabolism