You've probably seen the milligrams of cholesterol listed on the nutrition labels of the foods you eat. However, it's hard to know what that means unless you know how your body uses and stores cholesterol. Your liver plays the largest role in regulating cholesterol---it creates it and processes it for excretion.
Identification
Cholesterol is a fat-like, waxy material that your body produces all on its own. According to the American Heart Association, your genetic makeup determines how much cholesterol your body will produce---some people produce far more than others, no matter what their diets consist of. Your body actually needs cholesterol in small amounts to help digest fat and produce certain hormones. The National Heart Lung and Blood Institute reports that your brain, liver, skin, heart and intestines all contain cholesterol.
Sources
According to the American Heart Association, your liver and other cells produce about 75 percent of your total cholesterol, with the remaining 25 percent coming from food. Foods like fruits, veggies and grains will never contain cholesterol. Only animal products like meat, eggs and milk contain this substance. Saturated fats, trans fats and natural dietary cholesterol can all contribute to a buildup and eventual surplus of cholesterol in your body.
Types
The American Heart Association describes four components to your cholesterol "count": LDL, HDL, Lp(a) and triglycerides. While triglycerides are fats rather than cholesterol, they often indicate the presence of too much cholesterol. Lp(a) is similar to LDL cholesterol, posing a significant risk for arterial buildup. Both LDLs, or low-density lipoproteins, and HDLs, or high-density lipoproteins, carry cholesterol throughout the body. "Bad" LDL allows cholesterol to stick to the walls of your arteries, which can eventually cause a stroke or heart attack. "Good" HDL takes excess cholesterol to your liver, where it's processed for excretion.
Cholesterol and the Liver
Your liver does more than create your body's natural supply of cholesterol---it's also responsible for clearing away anything left over. According to Professors Tom Linder and Anna Melby of the University of Washington, your liver controls three important cholesterol-related functions. It synthesizes very low-density lipoproteins, that deliver energy-packed triacylglycerol to your cells and then return to the liver. Your liver transforms these lipoproteins into LDL, which transports cholesterol to your cells and then returns to your liver, where it's secreted in bile or converted to bile salts. Your liver also creates HDL, which travels through the body to capture and bring back extra cholesterol for disposal.
Anti-Cholesterol Statin Drugs
When a low-fat diet and exercise can't reduce your body's cholesterol levels naturally, your doctor may prescribe statin drugs. Statins block an enzyme in your liver, preventing it from producing cholesterol. According to the Mayo Clinic, sometimes these drugs can have the opposite effect, increasing your liver enzymes. Small increases are usually manageable, they report, but large increases can cause permanent liver damage and generally require you to stop taking the drug. A blood test is the only way to tell how the drug is affecting your enzyme level.
References
- American Heart Association: About Cholesterol
- National Heart Lung and Blood Institute: Why Lower Cholesterol Levels
- American Heart Association: Good vs. Bad Cholesterol
- University of Washington: Cholesterol, lipoproteins and the liver
- Mayo Clinic: Statins: Are these cholesterol-lowering drugs right for you?
