What causes high cholesterol?

What is cholesterol?

Cholesterol is present in every cell of the body. The body produces cholesterol, but people also consume it in food. It is an oil-based substance and does not mix with blood, which is water-based.

It has four primary functions:

• contributing to the structure of cell walls
• making up digestive bile acids in the intestine
• allowing the body to produce vitamin D
• enabling the body to make certain hormones

Cholesterol travels around the body in lipoproteins. Two types of lipoprotein carry the parcels of cholesterol:

• Low-density lipoprotein (LDL): Cholesterol that travels in this way is unhealthful or “bad” cholesterol.
• High-density lipoprotein (HDL): Cholesterol that is present in HDL is known as “good” cholesterol.

It is also important to take into account triglycerides and total cholesterol:

• Triglycerides: This is a type of fat the body uses for energy. High triglyceride levels combined with high LDL (bad) cholesterol or low HDL (good) cholesterol can increase the risk of heart attack and stroke.
• Total cholesterol: The complete amount of LDL cholesterol, HDL cholesterol, and triglyceride levels in the blood.

Read on to learn more about cholesterol levels.

Causes of high cholesterol

Cholesterol in the body mostly comes from the liver. However, every cell in the body can also produce it.

Several factors can lead to increased LDL levels. Some of these include:

Genetic features

Some people have high cholesterol levels due to their genes. Familial hypercholesterolemia is an inherited disease, and people with this condition have increased blood levels of LDL cholesterol.

Dietary factors

High cholesterol can result from a diet high in fat. Reducing the intake of fat in the diet helps manage cholesterol levels. In particular, it is helpful to limit foods that contain:

• Cholesterol: This is present in animal foods, meat, and cheese.
• Saturated fat: This occurs in some meats, dairy products, chocolate, baked goods, and deep-fried and processed foods.
• Trans fats: This occurs in some fried and processed foods.

Learn more about high cholesterol foods.

Stress

Stress refers to the way the body responds to pressures from challenging situations in life. Chronic stress can negatively impact health and may contribute to high cholesterol levels.

However, stress itself does not directly increase cholesterol. Instead, stress may cause a person to adopt unhealthy lifestyle choices to help manage stress levels. For example, stress can result in an unhealthy dietary pattern, smoking, and consuming alcohol.

Learn more about how stress affects cholesterol levels.

Sedentary lifestyle

Evidence notes that living a sedentary lifestyle may contribute to high LDL levels and lower HDL levels.

For example, a 2021 study indicates that a reduction in physical activity results in an increase in LDL levels. As such, living a sedentary lifestyle can not only increase cholesterol levels, but increases the risk of cardiovascular health conditions.

Medications

People who take certain drugs may have higher total and LDL cholesterol levels and lower HDL levels.

Commonly known medications that can have a negative effect on lipid levels include:

• certain cardiovascular medications, such as thiazide or loop diuretics
• antipsychotics
• anticonvulsants
• hormones
• certain immunosuppressives
• SGLT2 inhibitors to treat diabetes
• progestins, anabolic steroids, and corticosteroids

Health conditions

Some health conditions increase the chance of developing high cholesterol. These include:

• diabetes
• high blood pressure
• obesity
• liver or kidney disease
• polycystic ovary syndrome
• pregnancy and other conditions that increase levels of female hormones
• underactive thyroid gland
• nephrotic syndrome

Read on to learn more about where cholesterol comes from.

Other risk factors

Having certain risk factors can increase the chance of having high cholesterol. These include:

• excess weight or obesity
• age — 45 years and over for males and 55 years and over for females
• smoking

Levels and ranges of cholesterol

High cholesterol is a significant risk factor for coronary heart disease and a cause of heart attacks.

A buildup of cholesterol is part of the process that narrows arteries, called atherosclerosis. In atherosclerosis, plaques form and cause restriction of blood flow.

For this reason, doctors recommend keeping total and LDL cholesterol levels within certain ranges. They measure cholesterol in milligrams per deciliter (mg/dL).

The table below shows optimal cholesterol levels for most people, according to the Centers for Disease Control and Prevention (CDC).

Preventing high cholesterol

Knowing the causes of high cholesterol can help a person reduce or manage their cholesterol levels, including:

• eating a heart-healthy diet
• exercising regularly
• avoiding smoking
• achieving and maintaining a moderate weight

Other factors that may increase risk include:

• family history
• ethnicity
• certain health conditions that increase the risk of high cholesterol, such as chronic kidney disease or chronic inflammatory conditions
• unhealthy lifestyle habits
• certain medications
• being between ages 40 and 59
• between a male ages 20 and 39, or a female after menopause

Taking these factors into consideration will lead to a more personalized approach to the treatment and prevention of high cholesterol levels.

Frequently asked questions

Below are some commonly asked questions on the causes of high cholesterol.

What foods will cause high cholesterol?

Following a nutritious, balanced diet is one way to help with moderate cholesterol levels. According to the American Heart Association, a person may wish to avoid foods containing saturated fats. Examples include red meat, sausages, bacon, and organ meats such as kidney and liver.

Does stress increase cholesterol?

Stress may increase cholesterol levels. This can happen indirectly through adopting less healthy habits as a coping method. There may also be a direct biological link. However, more research is necessary on this topic.

Can alcohol cause high cholesterol?

Alcohol does not contain cholesterol. However, a high alcohol intake of over 30 grams (g) per day may have a negative effect on lipid or cholesterol profiles. Researchers are still investigating the link between the two.

A standard drink is any beverage containing 14 g of pure alcohol. Therefore, two standard drinks per day contain around 28 g.

What is the normal cholesterol level by age?

Cholesterol levels typically increase with age. A healthy total cholesterol level for a person under the age of 19 years is less than 170mg/dL, while for people aged 20 years or older it is 125 to 200 mg/dL.

A person’s doctor can provide them with more information about what their cholesterol level should ideally be based on their age and other factors.

How do you reduce cholesterol in your body?

To reduce or manage cholesterol in the body, a person can get enough physical exercise and achieve and maintain a moderate weight. They can also choose foods that are lower in trans fats and highly processed foods.

What reduces cholesterol quickly?

A doctor may prescribe medication alongside lifestyle changes to help reduce cholesterol more quickly. Examples of high cholesterol medications include statins, bile acid sequestrants, niacin, fibrates, and injectable PCSK9 inhibitors.

Summary

Cholesterol is an essential substance that the body produces but which people also consume in foods such as meat, dairy, and poultry products.

Some people have a family history of high cholesterol, and genetic factors may play a role.

Eating a heart-healthy diet and exercising regularly are some lifestyle choices people can make to manage their cholesterol levels.