Blood Cholesterol – Causes, Symptoms, Treatment

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Blood Cholesterol/Cholesterol is a waxy, fat-like substance that’s found in all the cells in your body. Your body needs some cholesterol to make hormones, vitamin D, and substances that help you digest foods. Your body makes all the cholesterol it needs. Cholesterol is also found in foods from animal sources, such as egg yolks, meat, and cheese.

If you have too much cholesterol in your blood, it can combine with other substances in the blood to form plaque. Plaque sticks to the walls of your arteries. This buildup of plaque is known as atherosclerosis. It can lead to coronary artery disease, where your coronary arteries become narrow or even blocked.

Cholesterol, a major sterol in animal tissues, has a significant function in the human body. Cholesterol is a structural component of cell membranes and plays an integral role in membrane fluidity. Cholesterol is also important in the synthesis of lipid rafts which are needed for protein sorting, cellular signaling, and apoptosis [rx]. The characteristic structural feature of cholesterol is a fused four hydrocarbon ring referred to as a steroid nucleus, and a hydrocarbon tail consisting of eight hydrocarbon chain [rx]. The cholesterol ring is the precursor of steroid hormones including estrogen, progesterone, testosterone, as well as vitamin D. As a hydrophobic molecule, cholesterol is transported in the blood via spherical macromolecules in the plasma termed lipoproteins including chylomicrons, VLDL, LDL, and HDL.

What are HDL, LDL, and VLDL?

HDL, LDL, and VLDL are lipoproteins. They are a combination of fat (lipid) and protein. The lipids need to be attached to the proteins so they can move through the blood. Different types of lipoproteins have different purposes:

  • HDL – stands for high-density lipoprotein. It is sometimes called “good” cholesterol because it carries cholesterol from other parts of your body back to your liver. Your liver then removes the cholesterol from your body.
  • LDL – stands for low-density lipoprotein. It is sometimes called “bad” cholesterol because a high LDL level leads to the buildup of plaque in your arteries.
  • VLDL – stands for very low-density lipoprotein. Some people also call VLDL “bad” cholesterol because it too contributes to the buildup of plaque in your arteries. But VLDL and LDL are different; VLDL mainly carries triglycerides and LDL mainly carries cholesterol.

Causes of Blood Cholesterol 

An unhealthy lifestyle is the most common cause of high “bad” LDL cholesterol or low “good” HDL cholesterol. However, genes that you inherit from your parents, other medical conditions, and some medicines may also cause unhealthy cholesterol levels.

Unhealthy lifestyle habits

Unhealthy habits such as these are a common cause of unhealthy cholesterol levels:

  • Unhealthy eating habits –  such as eating lots of bad fats. One type, saturated fat, is found in some meats, dairy products, chocolate, baked goods, and deep-fried and processed foods. Another type, trans fat, is in some fried and processed foods. Eating these fats can raise your LDL (bad) cholesterol.
  • Lack of physical activity – with lots of sitting and little exercise. This lowers your HDL (good) cholesterol.
  • Smoking, which lowers HDL cholesterol, especially in women. It also raises your LDL cholesterol.
  • Eating a lot of foods high in saturated fats or trans fats – which increase “bad” LDL cholesterol. Saturated fats are found in fatty cuts of meat and dairy products. No more than 10% of your daily calories should come from saturated fats. Trans fats are often found in packaged snacks or desserts. Read the label and eat as little food with trans fats as possible.
  • Lack of physical activity, such as spending a lot of time in front of a TV or computer. These patterns are linked with lower levels of “good” HDL cholesterol.
  • Smoking, which lowers HDL cholesterol, particularly in women, and raises LDL cholesterol.
  • Stress, which may raise levels of certain hormones, such as corticosteroids. These can cause your body to make more cholesterol.
  • Drinking too much alcohol or binge drinking, which can raise your total cholesterol level.


  1. Some people may develop high “bad” LDL cholesterol because of mutations, or changes, in their genes. These may be passed from parent to child, which can cause familial hypercholesterolemia. If you have a family history of high blood cholesterol, it may be more difficult for your body to remove LDL cholesterol from your blood or break it down in the liver.

Family history

  • Family members usually have similar cholesterol levels. This suggests that your genes can raise your risk of having unhealthy cholesterol levels.
  • In addition, your genes may raise your risk for another type of “bad” cholesterol. High levels of lipoprotein-a, also called Lp(a), may mean you are at high risk of heart or blood vessel diseases, even if your other cholesterol levels are healthy. Genes determine how much Lp(a) you have. Your Lp(a) level is unlikely to change much from childhood to old age.
  • Lp(a) is not usually part of a routine lipid panel. Your doctor may order an Lp(a) test if you have a family history of early heart or blood vessel disease, such as heart attack, or do not know your family medical history. If you have a high Lp(a) level, your doctor may prescribe a statin to prevent heart and blood vessel disease, even if your other cholesterol levels are in the healthy range.

Other medical conditions

Some medical conditions may raise LDL cholesterol levels or lower HDL cholesterol.

  • Chronic kidney disease
  • Diabetes
  • HIV infection
  • Hypothyroidism
  • Lupus erythematosus
  • Menopause
  • Multiple myeloma
  • Overweight and obesity
  • Polycystic ovary syndrome (PCOS)
  • Pregnancy
  • Sleep apnea


Some medicines that you take for other health problems can raise your level of “bad” LDL cholesterol or lower your level of “good” HDL cholesterol.

  • Antiretroviral medicines – used to treat HIV
  • Arrhythmia medicines – such as amiodarone
  • Beta-blockers – for relieving angina chest pain or treating high blood pressure
  • Chemotherapy medicines – used to treat cancer
  • Diuretics – such as thiazide to treat high blood pressure
  • Immunosuppressive medicines – such as cyclosporine, to treat inflammatory diseases or to prevent rejection after organ transplant
  • Retinoids – to treat acne
  • Steroids – such as prednisone, to treat inflammatory diseases including lupus, rheumatoid arthritis, and psoriasis

Risk Factors– Blood Cholesterol

Your risk for high blood cholesterol may be higher because of your age, family history and genetics, race or ethnicity, or sex.

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Unhealthy levels of cholesterol can affect people of all ages, even young children. However, high cholesterol is most commonly diagnosed in people between the ages of 40 and 59. As you age, your body’s metabolism changes. Your liver does not remove “bad” LDL cholesterol as well as it did when you were young. These normal changes may increase your risk for developing high blood cholesterol as you get older.

Race or ethnicity

Your race or ethnicity may affect your risk of high blood cholesterol.

  • Overall, non-Hispanic white people are more likely than other groups to have high levels of total cholesterol.
  • Asian Americans, including those of Indian, Filipino, Japanese, and Vietnamese descent, are more likely to have high levels of “bad” LDL cholesterol than other groups.
  • Hispanic Americans are more likely to have lower levels of “good” HDL cholesterol than other groups.
  • African Americans are more likely than other groups to have high levels of “good” HDL cholesterol. However, they are more likely to have other risk factors, such as high blood pressure, obesity, or diabetes, that may overcome the health benefit of higher HDL levels.

Between the ages of 20 and 39, men have a greater risk for high total cholesterol than women. Women are more likely to have high blood cholesterol than men at other ages. Women usually have higher levels of “good” HDL cholesterol.

Conditions and medicines that may raise a woman’s risk for high blood cholesterol include:

  • Birth control pills – However, not all types of birth control pills affect cholesterol levels, and the effect is not very strong.
  • Menopause – which lowers levels of female hormones that may protect against high blood cholesterol. After menopause, women’s levels of total and “bad” LDL cholesterol usually go up, while their levels of “good” HDL cholesterol go down.
  • Pregnancy – may cause your total cholesterol levels to rise, but usually not enough to cause problems for you or your unborn baby. Usually, cholesterol levels return to normal after pregnancy.
  • Heredity – High blood cholesterol can run in families.
  • Weight – Being overweight or having obesity raises your cholesterol level.
  • Race – Certain races may have an increased risk of high cholesterol. For example, African Americans typically have higher HDL and LDL cholesterol levels than whites.
  • Weight – Being overweight or having obesity raises your cholesterol level.

What health problems can high cholesterol cause?

  • If you have large deposits of plaque in your arteries, an area of plaque can rupture (break open). This can cause a blood clot to form on the surface of the plaque. If the clot becomes large enough, it can mostly or completely block blood flow in a coronary artery.
  • If the flow of oxygen-rich blood to your heart muscle is reduced or blocked, it can cause angina (chest pain) or a heart attack.
  • Plaque also can build up in other arteries in your body, including the arteries that bring oxygen-rich blood to your brain and limbs. This can lead to problems such as carotid artery disease, stroke, and peripheral arterial disease.

Symptoms of Blood Cholesterol

  • High “bad” LDL cholesterol usually does not cause symptoms, so most people do not know they have it until they are tested during a routine doctor’s visit. Very high levels may cause symptoms such as fatty bumps on your skin, called xanthomas, or grayish-white rings around the corneas in your eye, called corneal arcus. These mostly develop in people who have familial hypercholesterolemia.
  • Undiagnosed or untreated high blood cholesterol can lead to serious problems, such as heart attack and stroke.

Diagnosis  of Blood Cholesterol

There are usually no signs or symptoms that you have high cholesterol. There is a blood test to measure your cholesterol level. When and how often you should get this test depends on your age, risk factors, and family history. The general recommendations are:

For people who are age 19 or younger

  • The first test should be between ages 9 to 11
  • Children should have the test again every 5 years
  • Some children may have this test starting at age 2 if there is a family history of high blood cholesterol, heart attack, or stroke

For people who are age 20 or older

  • Younger adults should have the test every 5 years
  • Men ages 45 to 65 and women ages 55 to 65 should have it every 1 to 2 years

When looking at cholesterol levels, two different types are usually measured. The two types have different effects on cardiovascular health. In everyday language they are often referred to as “good” and “bad” cholesterol:

  • HDL cholesterol – HDL (high-density lipoprotein) cholesterol levels are a measure of the proportion of “good” cholesterol in your total cholesterol. Normal to high HDL cholesterol levels are associated with a lower risk of cardiovascular disease than low HDL cholesterol levels.
  • LDL cholesterol – LDL (low-density lipoprotein) cholesterol levels are a measure of the proportion of “bad” cholesterol. High LDL cholesterol levels are associated with a higher risk of cardiovascular disease.

The “total cholesterol” level is also measured. This describes how much cholesterol someone has in their blood overall. High total cholesterol levels tend to be unfavorable. It is best to measure total cholesterol and LDL cholesterol levels on an empty stomach. That is why people are asked to stop eating, and only drink water, twelve hours before being tested.

There is some disagreement about when cholesterol levels are “too high.” People are often diagnosed with hypercholesterolemia if their total cholesterol or LDL cholesterol is above the level that has been defined as “healthy.” HDL cholesterol levels below the threshold level are also considered to be unfavorable. These levels can be measured in two different units: either as milligrams per deciliter (mg/dL) or as millimoles per liter (mmol/L). The following levels are considered to be “good” in healthy people:

  • Total cholesterol – Levels below 200 mg/dL (5.2 mmol/L)
  • LDL cholesterol – Levels below 130 mg/dL (3.4 mmol/L)
  • HDL cholesterol – Levels above 40 mg/dL (1 mmol/L) in men and above 50 mg/dL (1.3 mmol/L) in women

Some experts criticize the use of pre-defined threshold levels because it means that a large number of people are considered to have a health problem. Based on these definitions, a 2010 study by the Robert Koch Institute found that more than half of all Germans had high cholesterol.

Treatment of Blood Cholesterol

Unhealthy blood cholesterol levels are treated with heart-healthy lifestyle changes and medicines. People who have familial hypercholesterolemia may need special procedures.

If a medical condition or medicine is causing your blood cholesterol problem, your doctor may treat the condition or change your medicine or its dose.

Talk with your doctor about your cholesterol levels, your risk of developing heart or blood vessel disease, other medical conditions you have, and your lifestyle. Your doctor can tell you about the benefits and side effects of medicines for lowering your blood cholesterol. Together, you can set up a treatment plan that will work for you.

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To help you lower your LDL cholesterol level, your doctor may talk to you about adopting a healthy lifestyle.

  • Heart-healthy eating – As recommended in the 2015–2020 Dietary Guidelines for Americans, heart-healthy eating includes limiting saturated and trans fats that are found in fatty cuts of meat, dairy products, and many packaged snacks or desserts. The guidelines also recommend eating fish high in omega-3 fatty acids, nuts, and certain vegetable oils such as olive oil. The Therapeutic Lifestyle Changes and DASH eating plans can help you lower your “bad” LDL cholesterol. These plans also encourage eating whole grains, fruits, and vegetables rather than refined carbohydrates such as sugar. Talk to your doctor about other nutritional changes that you can make.
  • Get regular physical activity – There are many health benefits to being physically active and getting the recommended amount of physical activity each week. Studies have shown that physical activity can lower LDL cholesterol and triglycerides and raise your “good” HDL cholesterol. Before starting any exercise program, ask your doctor what level of physical activity is right for you.
  • Aim for a healthy weight – If you have high blood cholesterol and overweight or obesity, you can improve your health by aiming for a healthy weight. Research has shown that adults with overweight and obesity can lower “bad” LDL cholesterol and raise “good” HDL cholesterol by losing only 3% to 5% of their weight.
  • Manage stress – Research has shown that chronic stress can sometimes increase LDL cholesterol levels and decrease HDL cholesterol levels.
  • Quit smoking – Visit Smoking and Your Heart and the NHLBI’s Your Guide to a Healthy Heart. Although these resources focus on heart health, they include basic information about how to quit smoking.
  • Get enough good quality sleep – Sleep helps heal and repair your heart and blood vessels. The recommended amount for adults is 7 to 9 hours of sleep a day.
  • Limit alcohol – Visit the National Institute on Alcohol Abuse and Alcoholism for resources on support and treatment to stop drinking.

Eat less fatty food

To reduce your cholesterol, try to cut down on fatty food, especially food that contains a type of fat called saturated fat. You can still have foods that contain a healthier type of fat called unsaturated fat.

Try to eat more
  • oily fish, like mackerel and salmon
  • brown rice, bread and pasta
  • nuts and seeds
  • fruits and vegetables
Try to eat less
  • meat pies, sausages, and fatty meat
  • butter, lard, and ghee
  • cream and hard cheese, like cheddar
  • cakes and biscuits
  • food that contains coconut oil or palm oil
Exercise more

Aim to do at least 150 minutes (2.5 hours) of exercise a week. Some good things to try when starting out include:

  • walking – try to walk fast enough so your heart starts beating faster
  • swimming
  • cycling

Try a few different exercises to find something you like doing. You’re more likely to keep doing it if you enjoy it.


Depending on your risk for complications such as heart attack and stroke and whether you are able to lower your high blood cholesterol levels with lifestyle changes alone, your doctor may prescribe medicine.

If your doctor prescribes medicines as part of your treatment plan, be sure to continue your healthy lifestyle changes. The combination of the medicines and heart-healthy lifestyle changes can help lower and control your blood cholesterol levels.

Doctors now have a range of medicines they can prescribe to treat high blood cholesterol.

  • Statins – are the most common medicine used to treat high blood cholesterol. Studies have shown that statins lower the risk of heart attack and stroke in people with high LDL cholesterol. Statins usually don’t cause side effects, but they may raise the risk of diabetes. However, this mainly happens in people already at high risk of diabetes, such as those who have prediabetes, overweight or obesity, or metabolic syndrome. Statins may also cause abnormal results on liver enzyme tests, but actual liver damage is extremely rare. Other rare side effects include muscle damage.
  • Ezetimibe – may be used if you have familial hypercholesterolemia, if statins cause side effects, or if statin treatment and lifestyle changes do not lower your “bad” LDL level enough. In rare cases, ezetimibe can cause liver injury.
  • Bile acid sequestrants – may be prescribed if you cannot take statins or if you need to lower your cholesterol even more than a statin taken alone. This medicine may cause diarrhea, make some other medicines less effective, or raise your blood triglyceride level.
  • PCSK9 inhibitors – are a type of medicine that you inject under your skin every 2 or 4 weeks. Your doctor may prescribe a PCSK9 inhibitor and a statin if you are at high risk of complications like heart attack or stroke, or if you have familial hypercholesterolemia. The most common side effects are itching, pain, or swelling at the place where you injected it.
  • Lomitapide – may be prescribed if you have familial hypercholesterolemia. If you take lomitapide, your doctor will check your liver enzymes regularly, because this medicine can cause liver injury. Your doctor will also recommend that you take vitamin E and other supplements.
  • Mipomersen – may also be used to treat familial hypercholesterolemia. If you take this medicine, your doctor will regularly check your liver because of the risk of liver injury.

Nutrient Composition of Most Commonly Consumed Cholesterol-Containing Foods

Food Item Unit One Egg a Beef b Cheese c Chicken d Butter e Shrimp f Two Eggs g
per per per per per Per per
50 gm 100 gm 100 gm 100 gm 100 gm 100 g 100 gm
Energy kcal 72 674 393 215 714 62 143
Protein g 6.28 8.21 25 18.6 12.56
Total lipid (fat) g 4.75 70.9 32.14 15.06 78.57 13.27 9.51
Carbohydrate, by difference g 0.36 0.88 0.72
Fiber, total dietary g
Sugars, total g 0.18 0.37
Calcium, Ca mg 28 26 714 11 53 56
Iron, Fe mg 0.88 0.72 0.9 0.32 1.75
Magnesium, Mg mg 6 5 20 12
Phosphorus, P mg 99 61 147 198
Potassium, K mg 69 96 189 138
Sodium, Na mg 71 26 607 70 566 142
Zinc, Zn mg 0.65 0.82 1.31 1.29
Copper, Cu mg 0.04 0.03 0.048 0.072
Manganese, Mn mg 0.01 0.019 0.028
Selenium, Se µg 15.3 6.6 14.4 30.7
Fluoride, F µg 0.6 1.1
Vitamin C, total mg 1.6
Thiamin mg 0.02 0.03 0.06 0.04
Riboflavin mg 0.23 0.04 0.12 0.457
Niacin mg 0.04 1.44 6.801 0.075
Pantothenic acid mg 0.77 0.16 0.91 1.533
Vitamin B-6 mg 0.09 0.11 0.35 0.17
Folate, total µg 24 6 47
Choline, total mg 147 59.7 293.8
Vitamin B-12 µg 0.45 0.73 0.31 0.89
Vitamin B-12, added µg
Vitamin A, RAE µg 80 41 160
Carotene, beta µg
Carotene, alpha µg
Cryptoxanthin, beta µg 4 9
Vitamin A, IU IU 270 137 2857 177 540
Lycopene µg
Lutein + zeaxanthin µg 252 503
Vitamin E (alpha-tocopherol) mg 0.53 0.3 1.05
Vitamin E added mg
Tocopherol, beta mg 0.01 0.01
Tocopherol, gamma mg 0.25 0.5
Tocopherol, delta mg 0.03 0.06
Vitamin D (D2 + D3) µg 1 0.3 0.2 2
Vitamin D3 (cholecalciferol) µg 1 0.3 2
Vitamin D IU 11 14 10 82
Vitamin K (phylloquinone) µg 3.4 1.5 0.3
h Fatty acids, total saturated g 1.56 29.5 19.64 4.31 50 3.126
Fatty acids, total monounsaturated g 1.83 30.9 6.24 3.658
Fatty acids, total polyunsaturated g 0.96 2.56 3.23 1.911
Fatty acids, trans g 0.02 0.097 0.038
i Cholesterol mg 186 99 107 75 214 124 372
Amino Acids
Tryptophan g 0.08 0.05 0.207 0.167
Threonine g 0.28 0.33 0.767 0.556
Isoleucine g 0.34 0.37 0.924 0.671
Leucine g 0.54 0.65 1.35 1.086
Lysine g 0.46 0.69 1.509 0.912
Methionine g 0.19 0.21 0.493 0.38
Cystine g 0.14 0.11 0.249 0.272
Phenylalanine g 0.34 0.32 0.721 0.68
Tyrosine g 0.25 0.26 0.597 0.499
Valine g 0.43 0.41 0.902 0.858
Arginine g 0.41 0.53 1.169 0.82
Histidine g 0.15 0.26 0.544 0.309
Alanine g 0.37 0.5 1.089 0.735
Aspartic acid g 0.66 0.75 1.659 1.329
Glutamic acid g 0.84 1.23 2.714 1.673
Glycine g 0.22 0.5 1.223 0.432
Proline g 0.26 0.39 0.911 0.512
Serine g 0.49 0.32 0.657 0.971
Hydroxyproline g 0.09

Improving health with current research

Blood Cholesterol

Learn about the following ways the NHLBI continues to translate current research into improved health for people who have high blood cholesterol. Research on this topic is part of the NHLBI’s broader commitment to advancing heart and vascular disease scientific discovery.

  • NHLBI Guidelines for Cardiovascular Health and Risk Reduction in Children and Adolescents. We support the development of guidelines based on up-to-date research to evaluate and manage risk for heart and blood vessel complications, such as heart attacks, in children and adolescents. Research shows that having high blood cholesterol and other risk factors for heart and blood vessel disease during childhood raises your risk for developing plaque in your blood vessels in adulthood.
  • Advancing Research in HIV/AIDS-Related Heart and Blood Vessel Diseases. In 2019, the NHLBI became the primary steward of the Multicenter AIDS Cohort Study(MACS)/Women’s Interagency HIV Study (WIHS) Combined Cohort Study (MACS/WIHS-CCS). This trans-NIH collaborative research effort aims to understand and reduce the impact of chronic health conditions that affect people living with HIV. The MACS/WIHS-CCS will build on decades of research using thousands of men and women participants, to further our understanding of chronic heart, lung, blood, sleep, and other disorders associated with HIV.
  • Supporting Coordinated Community Interventions to Prevent Heart Disease. The NHLBI DECIPHeR (Disparities Elimination through Coordinated Interventions to Prevent and Control Heart Disease Risk) initiative is exploring strategies to prevent heart disease, including controlling cholesterol levels in the blood. The strategies will be matched to the needs and resources of communities across the United States
  • Federal Dietary Guidelines for Americans. We continue to provide medical, nutritional, and other scientific expertise to the United States Department of Agriculture and HHS that publish the 2015–2020 Dietary Guidelines for Americans with information about the latest science-based nutritional recommendations. With NHLBI input, the dietary guidelines are updated to reflect current research about the effect of eating patterns on blood cholesterol levels. For example, the 2015 guidelines showed that dietary cholesterol might not affect amounts of cholesterol in the blood as much as was thought in the past.
  • Global Leadership in Cardiovascular Health. We are proud to serve as a global leader and respond to legislative calls to increase U.S. global health efforts. The Health Inequities and Global Health Branch seeks to stimulate global health research, education, and training for many conditions, including high blood cholesterol.
  • Advancing Research in Dementia and Disability as well as Heart Attacks and Cardiovascular Deaths. In 2019, we co-funded with the National Institute on Aging a major study called Pragmatic Evaluation of Events and Benefits of Lipid-Lowering in Older Adults (PREVENTABLE). The researchers looked at the overall benefits and risks of cholesterol-lowering statins in adults age 75 or older without heart or blood vessel disease. The study will help determine whether a statin can help prevent dementia and disability in this age group, as well as heart attacks, while not increasing risks of adverse health outcomes.
  • South Asian Origin as a Key Risk Factor for Coronary Heart Disease. We supported the Mediators of Atherosclerosis in South Asians Living in America (MASALA) Study, the first long-term study to look at the factors leading to coronary heart disease in South Asians in the United States and guide prevention and treatment. The American Heart Association used MASALA data in its cholesterol guidelines, which recommend that South Asians be considered a high-risk group and therefore carefully considered for statin treatment.
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