Introduction
Cholesterol is a natural lipid that our bodies need to survive. Cholesterol is produced by the liver, and can be consumed through food products. The body then balances how much cholesterol it produces, depending on how much cholesterol you eat in your diet. At any time, both your cells and the bloodstream contain levels of cholesterol. According to the American Heart Association, as long as those levels stay balanced, the body has just enough to perform the tasks needed. However, when these levels get too high, it can form into hypercholesterolemia, or dangerously high cholesterol.
Types
Not all types of cholesterol are bad for you. In fact, there are two different types of cholesterol, each with their unique duties in the body. The first type is low-density lipoprotein (LDL) cholesterol. LDL cholesterol is considered "bad" cholesterol, as it is the type responsible for cholesterol-related diseases such as atherosclerosis. The second type of cholesterol is high-density lipoprotein (HDL) cholesterol. HDL cholesterol is considered "good" cholesterol, as it helps transport cholesterol back to the liver and out of the body.
Cell
One of the most important tasks that cholesterol performs involves the cells of your body. In fact, cholesterol makes up a large percentage of each of your cells, ranging from your internal organs to muscle tissue. This is due to the fact that cholesterol makes up the protective membrane surrounding each cell's internal organelles. Cholesterol allows the cell membrane to stay fluid, while at the same time keeping the cell from becoming too fluid that it can no longer hold its shape. Without this outer wall, the cell would die. Receptors on the outside of the cell grab cholesterol from the bloodstream as needed to keep the cell functioning correctly.
Hormones
Cholesterol also contributes as a building block for many of the essential hormones in your body. Most importantly, it contributes to glucocorticoids, mineralocorticoids and all of the sex hormones. Glucocorticoids are made in the adrenal glands and help in the metabolism of carbohydrates, which also helps control your blood sugar levels and blood pressure. Mineralocorticoids are also produced in the adrenal glands and help regulate the levels of water and minerals in your body. Your sex hormones include testosterone, estrogen and progesterone, and are involved in determining sex characteristics, fetal development, libido, and many other gender-specific duties in the body.
Transportation
HDL cholesterol is important because it functions to transport LDL cholesterol out of the body. As cholesterol levels get too high in the bloodstream, LDL cholesterol can begin to cling to the walls of the blood vessels and form plaque. This plaque can clog the vessels, creating problems such as atherosclerosis and heart disease. HDL cholesterol helps move LDL cholesterol out of the bloodstream and to the liver, which can process the LDL cholesterol into a form that can be excreted from the body as waste.
References
- American Heart Association
- Children's Diabetes Foundation
- Harvey et al., Biochemistry: 3rd Edition, Baltimore: Lippincott, 2005, pp. 235-238
