In our bodies, cholesterol serves three main purposes: It aids in the production of sex hormones which keep your bones, teeth, and muscles healthy. It’s a building block for human tissues; it’s part of the outer layer, or membrane, of all your body’s cells. Also, it assists in bile production in the liver which helps to digest the fats we eat
Cholesterol—a waxy compound that some have likened to soft candle wax—is a kind of sterol. Sterols are a type of fat found in the tissues of both plants and animals, although only animals have varying amounts of cholesterol. Your body manufactures much of the cholesterol it needs in the liver, but you can also obtain it through your diet. Animal products such as chicken, beef, eggs, or dairy products contain cholesterol.
The cholesterol in your blood comes from two sources: the foods you eat and your liver; about 80% is made in the liver during a complex 37-step process. Your liver makes all the cholesterol your body needs.
Once in the bloodstream, some cholesterol will be returned to the liver and broken down. It’s used to make bile acids which are released into the intestines to help with digestion – bile acids break down the fats in food.
A small number of bile acids will be removed from the body as a waste product in your poo. But most will be absorbed back into the blood, returned to the liver, and used again for digestion.
Some treatments for high cholesterol work by stopping bile from being absorbed back into the blood. The liver has to take more cholesterol out of the blood to make more bile, lowering your cholesterol levels.
Cholesterol and other fats are carried in your bloodstream as spherical particles called lipoproteins. The two most commonly known lipoproteins are low-density lipoproteins (LDL) and high-density lipoproteins (HDL).
Studies have found that lowering LDL cholesterol levels reduces heart disease and stroke. The most common cause of high LDL cholesterol is an unhealthy lifestyle. Excess body weight and eating a lot of animal fats are linked to high levels of LDL cholesterol.
Benefits
- There is cholesterol in every cell in your body, and it’s especially important in your brain, nerves, and skin. It plays a role in forming and maintaining cell membranes and structures.
Cholesterol can insert between fat molecules making up the cell, making the membrane more fluid. Cells also need cholesterol to help them adjust to changes in temperature.
- Cholesterol is essential for making a number of critical hormones, including the stress hormone cortisol. Cholesterol is also used to make the sex hormones testosterone, progesterone, and estrogen.2
- The liver also uses cholesterol to make bile, a fluid that plays a vital role in the processing and digestion of fats.
- Cholesterol is used by nerve cells for insulation.3
- Your body also needs cholesterol to make vitamin D. In the presence of sunlight, cholesterol is converted into vitamin D.
Good and Bad Cholesterol
If cholesterol is so necessary, why is it sometimes described as “bad” and at other times as “good?”
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- Low-density lipoproteins, sometimes called “bad cholesterol,” gets their bad reputation from the fact that high levels of it are associated with an increase in your risk of heart disease.4 LDL contains more cholesterol than protein, making it lighter in weight. LDL travels through the bloodstream and carries cholesterol to cells that need it. When it becomes oxidized, LDL can promote inflammation and force lipids to accumulate on the walls of vessels in the heart and the rest of the body, forming plaques. These plaques can thicken and may limit or completely block blood and nutrients to affected tissues or organs.
- HDL—or high-density lipoproteins—is also commonly referred to as “good cholesterol.” HDL is heavier than LDL because it contains more protein and less cholesterol. HDL gets its good reputation from the fact that it takes cholesterol from the cells and brings it to the liver. Having higher levels of HDL may also help lower your risk of developing cardiovascular disease.
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Cholesterol in the Blood
| What is LDL (low-density lipoprotein) cholesterol? | What is HDL (high-density lipoprotein) cholesterol? |
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| LDL (“bad”) cholesterol can contribute to the formation of plaque buildup in the arteries (atherosclerosis). This is linked to a higher risk for heart attack and stroke.
You want your LDL below 70 milligrams per deciliter (mg/dl). Here’s what helps:
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HDL stands for high-density lipoprotein. HDL levels should be around 50 mg/dL. Some people can raise HDL by::
Others may need medicine to get HDL to a beneficial level and should work with a healthcare provider on a treatment plan. |
Checking your blood cholesterol level
A cholesterol screening is an overall look at the fats in your blood. Screenings help identify your risk for heart disease. It is important to have what is called a full lipid profile to show the actual levels of each type of fat in your blood: LDL, HDL, triglycerides, and others. Talk with your healthcare provider about when to have this test.
What is a healthy blood cholesterol level?
For people who have a plaque in their arteries or who have other factors that put them at risk for cardiovascular disease, doctors recommend an ideal LDL level well below 70 mg/dl. For those without risk factors who have an LDL level at or above 190 mg/dl, the recommendation is to get this level down to below 100 mg/dl. People aged 40 to 75 who are living with diabetes and whose LDL is at 70 or above may need medication.
What treatments are available for high cholesterol?
Treatment may include:
- Addressing risk factors. Some risk factors that can be changed include lack of exercise and poor eating habits.
- Cholesterol-lowering medicines. Medicines are used to lower fats in the blood, particularly LDL cholesterol. Statins are a group of medicines that can do this. The two most effective types are atorvastatin and rosuvastatin. Other medicines that lower cholesterol levels are ezetimibe and PCSK9 inhibitors.
Cholesterol Statistics
According to the American Heart Association (AHA), about 95 million American adults have total blood cholesterol levels of 200mg/dl and higher.
Of those, about 28.5 million American adults have a level of 240 or above.
High cholesterol levels early in life may play a role in developing atherosclerosis as an adult.
What are triglycerides?
Triglycerides are another class of fat found in the bloodstream. The bulk of your body’s fat tissue is in the form of triglycerides.
Triglyceride levels and heart disease
The link between triglycerides and heart disease is being studied. But many people with high triglycerides also have other risk factors, like high LDL levels or low HDL levels.
What causes elevated triglyceride levels?
High triglyceride levels may be caused by health conditions like diabetes, hypothyroidism, kidney disease, or liver disease. Dietary causes of high triglyceride levels may include drinking a lot of alcohol and eating foods containing cholesterol, saturated fat, and trans fat.
What are the different types of cholesterol?
Cholesterol is a type of blood fat, and blood fats are known as lipids. Cholesterol and other lipids are carried in the blood and attached to proteins, forming tiny spheres, or “parcels” known as lipoproteins. So, lipoproteins are lipids plus proteins.
There are two main types of lipoproteins
When people talk about the different types of cholesterol, they’re usually talking about these lipoproteins:
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LDL cholesterol (low-density lipoprotein)
This is often called bad cholesterol because too much in the blood can lead to health problems. These lipoproteins contain lots of cholesterol. Their job is to deliver cholesterol to the cells where it’s needed. But if there’s too much LDL cholesterol in your blood it can build up in the arteries, clogging them up.
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HDL cholesterol (high-density lipoprotein)
This is often called good cholesterol because it helps prevent disease. They contain lots of protein and very little cholesterol. HDL cholesterol’s job is to carry cholesterol away from the cells, back to the liver, where it can be broken down and removed from the body.
There are other types of lipoproteins too
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VLDL (very low-density lipoproteins)
These are larger. They carry triglycerides plus some cholesterol from the liver around your body. They contain lots of fat and very little protein. If there is too much VLDL in your blood, fat can be laid down in your artery walls, clogging them up.
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IDL (Intermediate density lipoproteins)
These lipoproteins also carry cholesterol and triglycerides. They are in fact VLDL lipoproteins – after some of the triglycerides have been taken out of them. They sit between VLDL and LDL cholesterol in terms of how much fat they carry.
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Chylomicrons
These are the largest lipoprotein. They carry triglycerides from the gut to the liver after a meal. They are broken down in the liver and the fats are repackaged into the other lipoproteins.