In the blood, cholesterol is transported by lipoproteins known as high-density lipoprotein (HDL) and low-density lipoprotein (LDL). HDL takes cholesterol to the liver for release, while LDL brings it to the arteries. You want to aim for high HDL and low LDL levels.

Your body needs cholesterol to function properly, including making hormones and vitamin D, and supporting digestion.

Your liver generates enough cholesterol to handle these tasks, but your body doesn’t just get cholesterol this way.

Food is the main source of cholesterol, especially meat and dairy. If you eat a lot of these foods and have risk factors, your cholesterol levels may become elevated over time.

Lipoproteins are made of fat and proteins. They serve as carriers for cholesterol to move through your body.

HDL is popularly known as “good cholesterol” because it collects other types of cholesterol from the body and transports them to the liver to be released from the body.

LDL transports large amounts of cholesterol to the arteries for cell repair. Often called “bad cholesterol” because when it occurs in excess, it can build up in artery walls.

Too much cholesterol in the arteries may lead to a buildup of plaque known as atherosclerosis, which can increase the risk of blood clots.

If a blood clot breaks away and blocks an artery in your heart or brain, you may have a stroke or heart attack.

Plaque buildup may also reduce blood flow and oxygen to major organs. Oxygen deprivation to your organs or arteries may lead to other complications, like kidney disease or peripheral arterial disease.

Optimal levels of HDL can protect your body from LDL. HDL helps rid the body of excess LDL cholesterol, making it less likely to end up in the arteries.

Lifestyle factors are the main factor in cholesterol levels. You may have higher LDL levels and lower HDL levels if you:

  • have obesity
  • follow a diet high in red meat, full-fat dairy products, saturated fats, trans fats, and processed foods
  • have a large waist circumference (over 40 inches for males or over 35 inches for females)
  • do not engage in regular physical activity and exercise
  • use tobacco

In some cases, high LDL is inherited. This condition is called familial hypercholesterolemia (FH). FH is caused by a genetic mutation that affects the ability of a person’s liver to get rid of extra LDL cholesterol.

This may lead to high LDL levels and an increased risk of heart attack and stroke at a young age.

Read more about high cholesterol.

You may not even know if you have high cholesterol because it doesn’t cause noticeable symptoms.

The only way to find out your cholesterol levels is through a blood test that measures cholesterol in milligrams per deciliter of blood (mg/dL).

When you get your cholesterol numbers checked, you may receive results for:

  • Triglycerides: This number may vary per laboratory, but it should usually be below 150 mg/dL. Triglycerides are a common type of fat. If your triglycerides are high, your LDL is also high, or your HDL is low, your risk of developing atherosclerosis may be elevated.
  • HDL: The higher this number, the better. It should be at least higher than 50 mg/dL for females and 40 mg/dL for males.
  • LDL: The lower this number, the better. Experts recommend LDL to be no more than 130 mg/dL if you don’t have a history of heart disease, blood vessel disease, or diabetes. If you do have a history of these conditions, LDL should be no more than 70 mg/dL or 55 mg/dL if a doctor believes you are at an increased risk.
  • Total blood cholesterol: This includes your HDL, LDL, and 20% of your total triglycerides, and it should be within the normal range your laboratory sets.

Experts often recommend lifestyle changes to manage high LDL and total cholesterol levels, including:

Read more about exercising for heart health.

To boost your HDL levels, you may want to follow the same guidelines and avoid trans and saturated fats in your diet.

Read more about trans fats and saturated fats.

Sometimes lifestyle changes aren’t enough, especially if you have FH. You may need ongoing management with one or more cholesterol-lowering medications, such as:

  • statins to help your liver get rid of cholesterol
  • bile-acid binding medications to help your body use extra cholesterol to produce bile
  • cholesterol absorption inhibitors to prevent your small intestines from absorbing cholesterol and releasing it into your bloodstream
  • injectable medications that cause your liver to absorb more LDL cholesterol

Medications and supplements to reduce triglyceride levels may also be used, such as omega-3 fatty acids and fibrates.

Read more about management of high cholesterol.

LDL refers to a low-density protein that carries cholesterol to the arteries. If there’s too much LDL cholesterol, you may have a higher risk of heart disease and stroke.

HDL is a high-density protein that collects cholesterol from the body and takes it to the liver for removal. Optimal levels of HDL help the body get rid of LDL cholesterol, so the higher your HDL, the better.

A blood test can let you know how much LDL and HDL you have, and a doctor can advise on the next steps if you have high cholesterol.