High cholesterol

Your body uses a type of fat to work.

This fat is in your blood. Some fats are good for you. Other fats can be bad. Too much of the bad fat can be a problem. It can build up in your tubes. This makes it hard for blood to move.

You might see yellow spots near your eyes. Eating healthy food can help you stay well.

Your body needs a type of fat called cholesterol.

All animal cells use it to make parts called membranes. Cholesterol also helps make hormones. Because it cannot mix with water, it travels in the blood inside tiny particles. We call these particles lipoproteins.

Some lipoproteins are good, like HDL. Others can be bad if there is too much. High levels of bad ones, like LDL, can cause problems. This often happens because of diet, weight, or even genes. Some people are born with a condition called familial hypercholesterolemia. This is a disease passed down in a family.

You might see yellow patches near the eyes in these people.

Too much bad cholesterol can lead to atherosclerosis. This is when fatty plaques build up in your arteries. This build-up can make the tubes narrow. A blockage can even cause a heart attack or a stroke. To stay healthy, adults can eat less saturated fat. They can also stay active and keep a healthy weight.

Cholesterol is a type of fat that all animal cells need.

It helps cells build their outer walls, called membranes. It also helps the body make bile acids and steroid hormones. Because cholesterol cannot dissolve in water, it must travel through the blood in special packages. These packages are called lipoproteins. There are different kinds of lipoproteins, such as VLDL, IDL, LDL, and HDL. Some lipoproteins, like HDL, are considered protective for the body. Other types, like LDL, are linked to health risks if they are too high.

High cholesterol happens when there are too many lipids in the blood. This can happen for many different reasons. A person's diet can play a big role. Eating too much sugar or saturated fat can raise LDL levels. Trans fats are also risky because they raise LDL and lower the good HDL. Sometimes, the cause is not just food. Other health issues like type 2 diabetes or an underactive thyroid can raise levels. Some people are even born with a genetic condition. This is called familial hypercholesterolemia, which affects about one in 250 people.

Scientists and doctors have studied these fats for a long time. They use different ways to measure them. In the United States, doctors use milligrams per deciliter (mg/dL). In places like the United Kingdom and Canada, they use millimetres per litre (mmol/L). In the past, it was hard to measure LDL directly because it cost too much. Doctors often used a math formula called the Friedewald formula to estimate it. Now, they can use more direct methods to get a better picture. This helps them understand how different types of fat affect the body.

When cholesterol levels stay high for a long time, it can cause serious changes. This process is called atherosclerosis. It is when fatty plaques build up inside the arteries. These plaques can make the arteries narrow over many years. If a plaque breaks, it might cause a blood clot. A blockage in a heart artery can lead to a heart attack. A blockage in an artery to the brain can cause a stroke.

Some people may even see yellow patches near their eyelids called xanthelasma palpebrarum.

There are many ways to help keep cholesterol at a healthy level. For many adults, changing how they eat is a great first step. They might swap saturated fats for polyunsaturated fats. Staying active and keeping a healthy weight also helps. Some people might need to stop smoking or drink less alcohol. For people with very high levels from their genes, diet might not be enough. These people often need special medicines to lower their LDL. In very severe cases, doctors might even use surgery or a process called LDL apheresis.

High cholesterol, medically known as hypercholesterolemia, is a condition where there are high levels of cholesterol in the blood. It is a specific type of hyperlipidemia, which means having high levels of lipids, or fats, in the blood. It can also be called hyperlipoproteinemia if lipoprotein levels are high, or dyslipidemia if there are any abnormalities in lipid levels.

Cholesterol is a vital substance for all animal cells. It is used to build cell membranes, which are the outer walls of cells. It also serves as a precursor, or starting material, for bile acids and steroid hormones.

Because cholesterol cannot dissolve in water, it cannot travel through the blood alone. Instead, it moves within protein particles called lipoproteins. These particles are classified by how dense they are. There are very low density lipoproteins (VLDL), intermediate density lipoproteins (IDL), low density lipoproteins (LDL), and high density lipoproteins (HDL). While all these particles carry cholesterol, they have different roles. High levels of non-HDL cholesterol, particularly LDL, are linked to health risks. In contrast, higher levels of HDL are considered protective for the body.

Several factors can cause cholesterol levels to rise. Environmental factors include diet, weight, stress, and even loneliness. A diet high in sugar or saturated fats can increase total cholesterol and LDL. Trans fats are especially risky because they increase LDL and reduce the protective HDL. Medical conditions can also play a role. These include type 2 diabetes, obesity, an underactive thyroid, and certain other disorders. For some, the cause is strictly genetic. This is seen in familial hypercholesterolemia, which affects about one in 250 individuals. This condition can stem from mutations in genes like APOB, LDLRAP1, or PCSK9.

Longstanding high cholesterol can lead to a process called atherosclerosis. This is the build-up of fatty plaques inside the arteries, often called the hardening of the arteries. Over many decades, these atheromatous plaques can cause the arteries to narrow progressively. If a small plaque ruptures, it may cause a blood clot to form. This clot can obstruct blood flow entirely. A sudden blockage in a coronary artery can result in a heart attack. A blockage in an artery supplying the brain can cause a stroke. If the narrowing is gradual, it can cause tissue ischemia, which is a restriction in blood supply.

Ischemia can cause many different symptoms depending on where it happens. In the brain, a temporary ischemic attack might cause dizziness, difficulty speaking, or numbness on one side of the body. If the heart does not get enough blood, it may cause chest pain. Ischemia in the eyes can lead to temporary vision loss. In the legs, it might cause pain while walking. In the intestines, it can cause abdominal pain after eating. Some people with high cholesterol also show physical signs like xanthelasma palpebrarum, which are yellowish patches near the eyelids. Other signs include xanthomata, which are yellowish deposits on the tendons or skin.

Doctors use different measurements to diagnose high cholesterol. In the United States, they use milligrams per deciliter (mg/dL). In the United Kingdom and Canada, they use millimoles per liter (mmol/L). For total cholesterol, a level below 200 mg/dL is considered desirable in the U.S. In the UK, the National Health Service recommends a limit of 5 mmol/L for healthy adults. For LDL, a level below 100 mg/dL is most desirable. In the UK, the recommended limit for LDL is 3 mmol/L. These numbers are important, but doctors also consider a person's overall risk factors when interpreting them.

Treating high cholesterol often involves lifestyle changes. Adults are encouraged to avoid trans fats and replace saturated fats with polyunsaturated fats. Other helpful steps include quitting smoking, increasing physical activity, and maintaining a healthy weight. For people with very high levels due to genetics, diet alone is often not enough. These individuals usually require lipid-lowering medications, such as statins. In very severe cases, medical teams may perform LDL apheresis or even surgery to manage the condition.