Understanding cholesterol

In honor of September being National Cholesterol Education Month, Johns Hopkins is highlighting several resources available to university employees to prevent and control high cholesterol. The article Understanding Cholesterol, by School of Medicine physicians Shireen Khoury, Seth Martin, and Elizabeth Ratchford, is provided below, and Khoury will lead a live cholesterol webinar from noon to 1 p.m. on Wednesday, Oct. 20. In addition, you're reminded of free support available through your medical plan.

Webinar: A Conversation on Cholesterol—Managing Lipids to Prevent Cardiovascular Disease

Join Shireen Khoury, a vascular medicine and preventive cardiology fellow at Johns Hopkins Medicine, for an interactive discussion on identifying, preventing, and controlling cholesterol problems. You are invited to submit your questions on the topic of cholesterol when you register so that they can be addressed during the session. Register here.

Article: Understanding Cholesterol

By Shireen Khoury, Seth Martin, and Elizabeth V Ratchford, all of Johns Hopkins

What is cholesterol? What are lipids? Why are they important?

Cholesterol and other lipids are fatlike, waxy substances that circulate through the blood. Although the terms "cholesterol" and "lipids" are sometimes used to mean the same thing, cholesterol is one type of lipid that is commonly monitored on blood testing because of its effects on cardiovascular (heart and blood vessel) health. Cholesterol is made by the liver and is also consumed through foods in the diet. A certain amount of cholesterol within the body is normal—cholesterol is used to build cells and hormones for normal functioning. Elevated lipid levels (hyperlipidemia) or imbalanced lipid levels (dyslipidemia) can lead to heart and blood vessel disease, such as heart attack, stroke, or peripheral artery disease, or PAD. Hyperlipidemia and dyslipidemia are the medical terms used to describe cholesterol and lipid problems. It is important to recognize and treat these conditions to reduce the risk of cardiovascular disease.

What is meant by "bad" and "good" cholesterol?

What are the different lipids shown on a blood test?

There are a few main lipid types that are commonly measured in the blood, and each has a different role. Cholesterol is transported through the blood in packages called lipoproteins, which are made of both lipids and proteins together.

• LDL (low-density lipoprotein: "bad"): LDL cholesterol is harmful to heart and blood vessel health if it is too high. LDL holds a lot of cholesterol in its core and deposits cholesterol into body cells and artery walls, where it can build up. It is important to keep LDL levels under control to minimize these harmful effects.
• VLDL (very-low-density lipoprotein: "bad"): VLDL contains a lot of triglycerides in its core and turns into LDL as it loses some triglycerides.
• HDL (high-density lipoprotein: "good"): HDL cholesterol may be helpful to heart and blood vessel health. HDL holds more protein than cholesterol in its structure, and it does not contribute to cholesterol buildup in artery walls the way LDL does.

Triglycerides: Triglycerides are not cholesterol but are another common type of lipid in the body that stores extra calories. Elevated triglyceride levels can be harmful to heart health. The triglyceride level is significantly affected by diet.

Lp(a) (lipoprotein "little a") and Apo(B) (apolipoprotein B): Lp(a) and Apo(B) can also be measured, and high levels are linked to cardiovascular disease. Lp(a) is a lipoprotein mostly inherited through genes, and Apo(B) is the main protein found on LDL and VLDL. Lp(a) and Apo(B) levels are sometimes checked in high-risk patients as a separate lab test from the standard cholesterol panel but are not used as commonly as LDL, VLDL, and HDL to estimate cardiovascular risk.

What is the ideal cholesterol level?

The goal levels for cholesterol depend partly on a person's overall risk of cardiovascular disease and other health factors. For example, the target level for LDL is much lower in patients who have had a heart attack or stroke. There can also be differences in laboratory measurements or calculations used to determine values, so it is important to work with a physician to determine individual goals.

This article is an excerpt from the Vascular Disease Patient Information Page. Click here to read the full article.

More resources

Be sure to take advantage of free support through your medical plan provider. If you are a participant in CareFirst, learn more about its Health Coaching program, which provides individual coaching in target areas such as healthy eating, weight or stress management, and tobacco cessation. EHP offers care management services and health education to support participants in managing a variety of health concerns.