What is cholesterol?

Cholesterol is a waxy substance found in every cell in our bodies. It is necessary for production of cells as well as hormones and vitamin D. It also helps with digestion. Most cholesterol production happens in the liver and we produce enough of it on our own. The other source of cholesterol is from food, primarily “fatty” foods such as meats, whole-fat milk and cheese, which can cause the body to produce more cholesterol than it needs. 

You have probably heard about the two types of cholesterol: high-density lipoprotein (HDL, or “good” cholesterol) and low-density lipoprotein (LDL, or “bad” cholesterol). A good way to remember which is which is to think: “L” for low—the lowest of the low—the bad cholesterol. Having too much LDL flowing through the blood causes the LDL to stick to the walls of the arteries. Over time the LDL builds up to form plaque, which narrows the arteries and restricts blood flow, a condition known as atherosclerosis, which may lead to stroke or heart attack. Restricted blood flow is also a risk factor for hypertension (high blood pressure).

HDL, on the other hand, does not stick to the walls of the arteries and also has the ability to loosen and remove LDL from arterial walls. A healthy combination of both types of cholesterol is needed for optimal bodily function.

Triglycerides, another type of fat in the body, are also a component of cholesterol. Having high triglyceride levels along with unhealthy levels of LDL and HDL further increases your risk for stroke and heart attack.

Causes of high cholesterol

Having unhealthy cholesterol levels is mostly due to unhealthy behaviors, namely:

  • Eating a diet high in saturated fat
  • Living a sedentary (inactive) lifestyle
  • Being overweight
  • Smoking

If one or both of your parents, or even your grandparents, also had high cholesterol (hypercholesterolemia), you may also be more likely to have it. This simply means that your body has a tendency to produce more cholesterol than it needs.

Diagnosis and testing of high cholesterol

Cholesterol itself does not cause symptoms. The only way to know if you have high cholesterol and are at risk for coronary artery disease (heart disease) or stroke, is to get a blood test from your doctor. He or she can then explain your results to you and recommend a treatment plan that may include diet and lifestyle changes and cholesterol-lowering medication.


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