Cholesterol, a white, waxy substance found among the fats in your blood, is present naturally in animal foods, but the liver also manufactures it. Cholesterol aids in the production of cell membranes, insulates the nerves, and helps produce some hormones and vitamin D. There are two different classes of cholesterol: LDL, or low-density lipoprotein, and HDL, or high-density lipoprotein. LDL cholesterol sticks to the inside of arteries and clogs them, putting patients at risk for heart disease. HDL cholesterol, or "good" cholesterol, helps remove cholesterol deposits from the artery walls, which promotes heart health.
Heart Disease
Low HDL cholesterol is a marker for coronary heart disease risk, according to the University of Maryland Medical Center website. Reduced blood HDL may not effectively remove cellular cholesterol from the lining of the artery. As a consequence, the artery wall promotes the development of a fatty deposit called plaque. This accumulation of atherosclerotic plaque makes a blood vessel narrower and less flexible, making it difficult for the blood to flow through them; this often results in a clogged artery. A heart attack is most likely to occur when the main coronary artery, leading to the heart, becomes blocked and the oxygenated blood supply to the heart is cut off.
Stroke
Low HDL levels are associated with an increased risk for stroke, especially in elderly people. Cholesterol cannot dissolve in the blood, so it must be transported to your body's cells by either low-density lipoproteins or high-density lipoproteins. High-density lipoproteins remove excess cholesterol from arterial walls and return them to the liver for disposal from the body. Low HDL levels are linked to the development of atherosclerosis, a common arterial disorder that is characterized by hardening of the arteries. A stroke can happen when a cholesterol-clogged carotid artery does not carry oxygen-rich blood to your brain.
High Blood Pressure
People with low HDL cholesterol often have high blood pressure. Generally, reduced HDL cholesterol correlates with increased concentrations of LDL cholesterol. High LDL cholesterol can cause a blood vessel thicker and stiffer by depositing saturated fats along the artery walls. This in turn narrows the lumen or diameter of blood vessels through which blood flows, causing stress on vessel walls; this may cause high blood pressure.
References
- University of Michigan Health System: Cholesterol Patient Education Handout
- University of Nebraska, Lincoln: Stroke and Cholesterol
- Texas AgriLife Extension Service: Cholesterol and Fats in Our Diet
- Lipids Online: Low HDL Cholesterol Increases Stroke Risk for Elderly Type 2 Diabetics
- University of Chicago: High Blood Cholesterol What You Need to Know
- University of Maryland Medical Center: Heart Disease: Tips for Prevention
