Cholesterol is a soft, waxy type of fat obtained through diet and also produced by the liver. Because high cholesterol levels are associated with cardiovascular disease, cholesterol has gotten a bad reputation. But cholesterol is essential for survival and is particularly abundant in cell membranes.
Types
Large amounts of low-density lipoprotein (LDL), the so-called "bad" cholesterol, tend to build up in arteries as plaque, slowing blood flow. High-density lipoprotein (HDL), the good cholesterol, carries excess fat through the bloodstream to the liver for removal.
Function
Cholesterol maintains cell membrane fluidity while also adding firmness, thus preventing any extremes in membrane structure. Cholesterol allows some substances through the membrane and prevents others from entering, and so maintains cell integrity.
Communication
Cholesterol also facilitates signaling between cells, allowing them to communicate with each other and function as a group.
Other Purposes
Cholesterol provides a protective coat around peripheral nerves and is necessary for the production of certain hormones. A study published in the October 2007 issue of the journal "Pediatrics" found a link between low cholesterol levels in pregnant women and premature births as well as lower birth weight in full-term babies. The Mayo Clinic notes low cholesterol levels are associated with depression and anxiety.
Expert Insight
The Mayo Clinic recommends total cholesterol levels be below 200 mg per deciliter (mg/dL), while LDL cholesterol levels should be below 100 mg/dL. Total cholesterol levels from 150 to 200 mg/dL are generally considered normal.
