You may have heard that there are two types of cholesterol-- "good" and "bad"-- but do you know the purpose of cholesterol?
Cholesterol helps cells form membranes and Vitamin D, an essential building block for hormones. Cholesterol also helps produce bile, aiding in digestion and nutrient absorption. While the liver produces enough cholesterol for the human body, a diet that is high in saturated fat (butter, meat, cheese, eggs, and milk) can increase the amount of cholesterol in the blood.
Cholesterol circulates in the bloodstream as part of lipoproteins and lipid proteins:
- High-density lipoprotein (HDL) -- "Good" cholesterol; transports cholesterol from the blood in the arteries to the liver where it is broken down and removed from the body
- Low-density lipoprotein (LDL) -- "Bad" cholesterol; deposits cholesterol in the cells and tissues of the body
High levels of total cholesterol (all of the cholesterol carried by lipoproteins) increase the risk of hardening arteries (known as atherosclerosis). Atherosclerosis thickens the artery walls, thereby narrowing the bloodstream, making it hard for blood to flow.
Atherosclerosis contributes to the following cardiovascular conditions:
- Heart attack
- Arterial disease in other parts of the body.
Physicians generally agree that high cholesterol constitutes a total blood cholesterol level of 200 milligrams per deciliter (mg/dl) or an LDL level of 160 mg/dl or more. The desired LDL level for patients with preexisting cardiovascular disease is less than 70 mg/dl.
Symptoms and Risk Factors
While high cholesterol itself does not cause symptoms, individuals with high cholesterol may experience symptoms from related conditions.
These symptoms include:
- Chest pain
- Muscle pain
- Muscle weakness from ischemia (blood flow that is insufficient to provide enough oxygen)
Risk factors-- besides eating a diet high in saturated fat-- that contribute to high cholesterol include:
- Age -- men older than 45 and women older than 55 are at an increased risk for high cholesterol
- Family history of atherosclerosis
- Having high blood pressure and/or diabetes
- Physical inactivity
- Inherited high cholesterol (inherited hyperlipoproteinemia) often causes cholesterol levels to be 2-3 times higher than normal.