CHOLESTEROL - High Cholesterol Overview

Cholesterol is a waxy, fatlike substance that the body needs to function normally. Cholesterol is naturally present in cell walls or membranes everywhere in the body, including the brain, nerves, muscles, skin, liver, intestines, and heart.

The body uses cholesterol to produce many hormones, vitamin D, and the bile acids that help to digest fat. It takes only a small amount of cholesterol in the blood to meet these needs. If a person has too much cholesterol in the bloodstream, the excess may be deposited in arteries, including the coronary arteries of the heart, the carotid arteries to the brain, and the arteries that supply blood to the legs. Cholesterol deposits are a component of the plaques that cause narrowing and blockage of the arteries, producing signs and symptoms originating from the particular part of the body that has decreased blood supply.

Blockage to the leg arteries causes claudication (pain with walking) due to peripheral artery disease. Carotid artery blockage may cause stroke, and blockage of the coronary arteries leads to angina (chest pain) and heart attack.

Coronary heart disease (CHD) is caused by cholesterol and fat being deposited in the walls of the arteries that supply nutrients and oxygen to the heart. Like any muscle, the heart needs a constant supply of oxygen and nutrients, which are carried to it by the blood in the coronary arteries. Narrowing of the arteries decreases that supply and can cause angina (chest pain) when the heart muscle does not receive enough oxygen. Cholesterol plaques can rupture, resulting in a blood clot formation that completely blocks the artery, stopping all blood flow and causing a heart attack, in which heart muscle cells die from lack of oxygen and nutrients.

Who has high cholesterol?

• Throughout the world, blood cholesterol levels vary widely. Generally, people who live in countries where blood cholesterol levels are lower, such as Japan, have lower rates of heart disease. Countries with very high cholesterol levels, such as Finland, also have very high rates of coronary heart disease. However, some populations with similar total cholesterol levels have very different heart disease rates, suggesting that other factors also influence risk for coronary heart disease.

• 71 million American adults (33.5%) have LDL, or "bad" cholesterol

• People of all ages and backgrounds can have high cholesterol.

Medically Reviewed by a Doctor on 6/4/2014

Medical Author: Benjamin Wedro, MD, FACEP, FAAEM

Medical Editor: Melissa Conrad Stöppler, MD, Chief Medical Editor

Source: http://www.emedicinehealth.com/