Definition: Defining the Meaning of Cholesterol
Cholesterol is an organic molecule. It is a sterol (or modified steroid), a lipid molecule and is biosynthesized by all animal cells because it is an essential structural component of animal cell membranes that is required to maintain both membrane structural integrity and fluidity. Cholesterol enables animal cells to not need a cell wall (like plants & bacteria) to protect membrane integrity/cell-viability and thus be able to change shape and move about (unlike bacteria and plant cells which are restricted by their cell walls).
High blood cholesterol presents a major risk factor for heart disease. Heart disease is the leading cause of death in America. Approximately seventeen-percent of all adults in America have high blood cholesterol. Cholesterol is a waxy, fat-like substance found in the body that is actually needed for it to function normally. The body produces sufficient amounts of cholesterol for its needs; when there is too much cholesterol in the body it is deposited in the arteries, to include arteries involved with the heart, potentially leading to a narrowing of these arteries and heart disease.
(See our Blood Cholesterol Level Chart)
The presence of high blood cholesterol does not produce symptoms; many people are unaware that they have an elevated blood cholesterol level.
Blood cholesterol may be checked easily and controlled. There are ways to keep blood cholesterol levels within a normal range. Cholesterol is carried in blood in particles referred to as, 'Lipoproteins.' Lipoproteins are made up of cholesterol on the inside with protein on the outside. There are two kinds of Lipoproteins, low-density lipoproteins (LDL's), and high-density lipoproteins (HDL's).
- LDL's are the major type of lipoprotein that carries cholesterol in the bloodstream to the body. They may lead to a buildup of cholesterol in the arteries and heart disease.
- HDL's are particles that carry cholesterol back to the liver in order to remove it from the body; higher levels of HDL are consider to be good.
Excessive amounts of either total or LDL cholesterol in the blood presents a risk for arthrosclerosis and heart disease. People may have an excess of cholesterol due to their diet and because of the rate at which cholesterol is processed in their body. The majority of the excess cholesterol comes from the person's diet. Cholesterol may build up on the person's artery walls in their body, a buildup referred to as, 'Plaque.' Over a period of time, plaque may cause the person's arteries to narrow, a process referred to as, 'Atherosclerosis.' As a result, less oxygen-rich blood can pass through. When the arteries that carry blood to the person's heart become affected, coronary artery disease may result. A heart attack happens when the person's coronary artery becomes completely blocked, either by plaque buildup or by a plaque that either ruptures or bursts causing a clot. The person may also develop angina due to plaque buildup. Angina occurs when the person's heart does not receive enough oxygen-rich blood.
If a doctor discovers that a person's blood cholesterol is too high, they may prescribe various forms of treatment depending on that person's risks for the development of heart disease. The forms of treatment may include lifestyle changes involving diet, physical activity, and weight control. The doctor may prescribe certain statin drugs in order to manage cholesterol levels. Lifestyle changes are still commonly a recommendation, even with medications. Everyone can do things to help keep their cholesterol levels within an average range.
Quick Facts: Cholesterol
- Human breast milk contains significant quantities of cholesterol.
- Major dietary sources of cholesterol include cheese, egg yolks, beef, pork, poultry, fish, and shrimp.
- The American Heart Association recommends testing cholesterol every five years for people aged 20 years or older.
- American Heart Association guidelines issued in 2013 indicates that patients taking statin medications should have their cholesterol tested 4 to 12 weeks after their first dose and then every 3 to 12 months thereafter.
- Approximately seventeen percent of Americans over age twenty have high cholesterol.
- In 2004 there were six and a half million doctor's office visits which included a cholesterol test either being performed or ordered.
- Among African-Americans, approximately 16.6% of women and 12.5% of men have high cholesterol.
- Among Mexican-Americans, 17.4% of women and 17.0% of men have high cholesterol.
- Among White-Americans, 17.4% of women and 17.0% of men have high cholesterol.
- The average blood cholesterol level in adult Americans is about 203 mg/dL.
- The percentage of persons aged 20-74 years with high cholesterol dropped from 33% in 1960-1962 to 17% in 1999-2002. During that same time period, the average blood cholesterol levels in adults dropped from 222 mg/dL to 203 mg/dL.
- The National Cholesterol Education Program recommends that all adults have their cholesterol checked once every 5 years.
- In 2005, 73% of adults reported that that they had their cholesterol checked within the previous 5 years, according to data from CDC's Behavioral Risk Factor Surveillance System. Some 23% reported that they never had their cholesterol checked.
- According to data from CDC's Behavioral Risk Factor Surveillance System (2005), 75.7% of whites, 73.7% of African Americans, and 52% of Hispanics reported having had their cholesterol checked within the previous 5 years.