What is the difference between good and bad cholesterol?

Do you know what your cholesterol is? If so, do you know what the numbers mean? Bad cholesterol is a risk factor for heart disease that plays a part in building plaque in arteries. What our cholesterol looks like depends on three factors: genetics, diet and exercise.

Total cholesterol numbers don’t mean very much, which is why you have to look at the breakdown. Low-density lipoprotein (LDL), or "bad cholesterol," is more stable over time and is significantly affected by the ingestion of animal fats. Triglycerides are the free fats which run around in the bloodstream, vary more on a day-to-day basis and are affected by both fat and carbohydrate intake. If elevated, both of these parts of the total cholesterol put you at higher risk of heart disease.

High-density lipoprotein (HDL), or "good cholesterol," is the only number that you want to be high. Although very genetically based, it is positively affected by regular physical activity. High HDL is somewhat protective against heart disease.

Eating a more plant-based diet is helpful because there is no cholesterol in plants! Stay away from foods high in animal fat such as red meat (e.g., beef and pork), eggs, butter and cheese.

Dr. Marcus J. Cox, MD
Cardiologist (Heart Specialist)

Good cholesterol typically involves HDL levels that are considered cardioprotective. Bad cholesterol involves LDL levels that can show a link to cardiovascular risk. LDL can build up in the walls of the arteries and form a plaque that can narrow and ultimately block the blood flow, leading to heart attack and stroke. HDL can carry cholesterol from the arteries and back to the liver while slowing the buildup of plaque.

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Good cholesterol, known as high-density lipoprotein (HDL), brings cholesterol from the blood and blood vessels back to the liver for processing. Bad cholesterol, known as low-density lipoprotein (LDL), circulates cholesterol to the body. Many people have excess LDL, which can lead to plaques in blood vessels and atherosclerosis. People with plaques or atherosclerosis are at higher risk for strokes and heart attacks.

HDL (good) cholesterol protects against cardiovascular disease. For HDL, higher numbers are better. A level of less than 40 is low and is considered a major risk factor for cardiovascular disease. A level of 60 or higher is considered protective and better for you.

LDL (bad) cholesterol levels of 130 or below are desirable. A level of 160 or above is considered high, and as with your total cholesterol number, the higher this measurement is, the greater the risk for cardiovascular disease.

Good and bad cholesterol refer to carrier molecules or lipoproteins, HDL and LDL. Cholesterol itself may be good or bad. We need cholesterol for cellular integrity and cholesterol is produced in the liver even if we eliminate it from our diet for this reason.

The HDL carrier is protective and therefore "good" the LDL carrier tends to allow cholesterol to be deposited in our blood vessels and this is "bad."

By increasing your good cholesterol or HDL through exercise and diet, we can add protection against heart disease. Niacin in high doses can also raise our good cholesterol.

Similarly by lowering our bad cholesterol or LDL we can reduce our risk of heart attack and stroke. This can also be done through diet and exercise but sometimes medications are warranted. The statin medications are the most commonly prescribed.

When healthcare providers talk about “good” and “bad” cholesterol, they are describing the health effects of two forms of cholesterol - one form is thought to be good for you, and the other is bad. The “bad” cholesterol forms fatty deposits (plaques) in your blood vessels that can eventually narrow them. A narrowed blood vessel can starve your heart of blood, causing a heart attack, or deprive your brain of blood, which can lead to a stroke. The blood vessels that deliver oxygen to your legs and your kidneys also can be clogged, leading to peripheral artery disease (PAD) or renal artery disease. Health care providers often refer to the bad cholesterol by a name based on its chemical composition: low-density lipoprotein (LDL). In short, you want your LDL cholesterol level to be low, ideally under 159 milligrams/deciliter (mg/dL), or lower if you have other cardiovascular risk factors or a history of cardiovascular disease. The reason medical professionals encourage high levels of “good” cholesterol is that it prevents the bad cholesterol from building up in your blood vessels. It, too, is often referred to by a name based on its chemical composition: high-density lipoprotein (HDL). For men, HDL levels should be 40 mg/dL or higher. For women, the desired level is 50 mg/dL or higher.

Dr. Mehmet Oz, MD
Cardiologist (Heart Specialist)

Good cholesterol, or HDL, seems to protect against heart attacks. Bad cholesterol, or LDL, sticks to the inside walls of arteries. It helps form plaque, which can slow or block the flow of blood carrying oxygen and nutrients to your heart and brain. Watch this animation to learn more about cholesterol.

The difference between "good cholesterol" and "bad cholesterol relates to the type of carrier molecule that transports the cholesterol.

Cholesterol and other fats can't dissolve in water, which means they also can't dissolve in blood. Carrier molecules (also called apoproteins) are made of protein. When these apoproteins join with cholesterol, they form the compound lipoproteins. The amount of protein in the molecule determines the density of lipoproteins.

"Bad" cholesterol is low-density lipoprotein (called LDL). It is the major cholesterol carrier in the blood. Especially high levels of LDLs are associated with atherosclerosis, the build-up of plaques that narrow or block blood vessels.

"Good" cholesterol is high-density lipoprotein (called HDL). A greater level of HDL is thought to provide some protection against artery blockage (think of this as drain cleaner you pour down a clogged sink).

A third group of carrier molecules, called very low-density lipoproteins (or VLDL) are converted to LDL after delivering triglycerides to muscles and fat tissue.

Levels of HDL, LDL and total cholesterol are indicators for atherosclerosis and heart attack risk. Those with a cholesterol level of 275 or greater are at significant risk for a heart attack (200 or less is desirable). This is true even with a favorable HDL level. Those who have normal cholesterol levels but low HDL also are at increased risk for a heart attack.

Good HDL cholesterol prevents clogged arteries that are caused by bad LDL cholesterol sticking to the inside walls of blood vessels. The good cholesterol can help to remove some of the deposits in arteries that cause heart attacks and strokes. If you think your arteries as roads, then the bad cholesterol is like trash blocking a road and the good cholesterol is like garbage trucks that remove the trash.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.