What is cholesterol

What is cholesterol? Did you know it is harmless?

Pawel Malczewski
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Short Summary

The concept of cholesterol is commonly misunderstood. Many people confuse cholesterol with lipoprotein.

Lipoprotein is not cholesterol but a particle that transports cholesterol particles through the blood.

Cholesterol by itself does not cause/initiate the buildup of atherosclerotic plaque, but lipoproteins called LDL do. Cholesterol is only used as a building material once the damage is done.

For the purpose of this website, I am going to clarify what cholesterol is and what it does. For a quick answer click here.

Explanation

The following is a list of the most important characteristics of cholesterol in order to understand why there are so many myths about it. (1)Ridker PM, Rifai N, Rose L, Buring JE, Cook NR. Comparison of C-Reactive Protein and Low-Density Lipoprotein Cholesterol Levels in the Prediction of First Cardiovascular Events. N Engl J Med 2002; 347:1557-1565November 14, 2002. Available here. (2)Toth PP. The “Good Cholesterol”. Circulation.2005; 111: e89-e91. Available here. (3)Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. Executive Summary of The Third Report of The National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, And Treatment of High Blood Cholesterol In Adults (Adult Treatment Panel III). JAMA. 2001 May 16;285(19):2486-97. Available here. (4)Mosca L, Appel LJ, Benjamin EJ, Berra K, Chandra-Strobos N, Fabunmi RP, et al. Evidence-Based Guidelines for Cardiovascular Disease Prevention in Women. Circulation.2004; 109: 672-693. Available here. (5)American Diabetes Association. Dyslipidemia Management in Adults With Diabetes. Diabetes Care January 2004 vol. 27 no. suppl 1 s68-s71. Available here. (6)Centers for disease control and prevention. Cholesterol. Available here. (7)U.S. Department of Health and Human Services. Get Your Cholesterol Checked. Available here. (8)Hanukoglu I. Steroidogenic enzymes: structure, function, and role in regulation of steroid hormone biosynthesis. The Journal of Steroid Biochemistry and Molecular Biology. Volume 43, Issue 8, December 1992, Pages 779–804. Available here. (9)Lecerf JM, de Lorgeril M. Dietary cholesterol: from physiology to cardiovascular risk. British Journal of Nutrition / Volume 106 / Issue 01 / July 2011, pp 6-14. Available here.

What is cholesterol?

  • Cholesterol is a type of fat molecule used as part of the structure of every cell in the body;
  • Cholesterol is produced by almost every cell in the body, except for brain cells, with the liver being the major producer;
  • Cholesterol is not water soluble (called hydrophobic – “afraid of water”), which means that it does not mix well with blood. It is carried through blood inside a transport mechanism. Otherwise, it just floats and doesn’t move along with the blood flow;
  • The transport mechanism of cholesterol is called lipoprotein, which has a water friendly layer on the surface and keeps all of the fatty particles inside, separated from the blood. Think of them as tiny submarines carrying a load (cholesterol and other lipids) through tunnels filled with blood.
  • Chemical structure of cholesterol.
    Cholesterol is a molecule containing 27 carbon atoms. Structurally, it consists of three parts: a hydrocarbon tail, a ring structure with 4 hydrocarbon rings and a hydroxyl group.

Cholesterol structure

Where does cholesterol come from?

  • The biggest source of cholesterol comes from the re-absorbed cholesterol made by our own body;
  • Our bodies are usually capable of maintaining a healthy cholesterol level, by increasing or decreasing it when needed, although a combination of genetics, diet and lifestyle may also have an effect on cholesterol levels;
  • A large portion of dietary cholesterol comes in a form which is not absorbed but excreted (called esterified cholesterol – CE); (10)Djoussé L, Gaziano JM. Dietary cholesterol and coronary artery disease: A systematic review. Current Atherosclerosis Reports. November 2009, 11:418. Available here.
  • The small portion of cholesterol derived from food that is absorbed has a very little effect on the overall level of cholesterol in the body. Some foods, however, such as carbohydrates, may increase the production of cholesterol in your body. (article coming soon..)

What are the functions of cholesterol? Why it is harmless?

Cholesterol is essential to our survival, since:

  • It is an important component of cell membranes, since it provides their structural integrity and fluidity;
  • It is used in the production of steroid hormones, such as testosterone, cortisol and estrogens;
  • It is used in the production of bile acids;
  • It is used in the production of vitamin D.

Cholesterol can be used to form a plaque on the artery wall, but only in presence of specific factors such as damaged artery walls, high blood pressure, high level of small and dense lipoproteins. (read more..) Therefore, by itself cholesterol doesn’t pose any health threats. It is possible to have a higher than usual total cholesterol and a perfectly good cardiovascular health provided that other risk factors are not present.

Epidemiological studies don’t find an association between dietary cholesterol and cardiovascular diseases, so eating eggs is not unhealthy!

Cholesterol test

The common cholesterol tests do not give conclusive results, since they measure the amount of cholesterol particles instead of a number of small, dense LDL lipoproteins responsible for dumping its contents (building material of the plaque) in the artery walls.

Conclusion

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Cholesterol is an essential component in our bodies and has many vital functions. Without it we wouldn’t be able to survive. Cholesterol itself doesn’t cause the plaque buildup but is only a building material just like calcium and fat molecules.

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References   [ + ]

1. Ridker PM, Rifai N, Rose L, Buring JE, Cook NR. Comparison of C-Reactive Protein and Low-Density Lipoprotein Cholesterol Levels in the Prediction of First Cardiovascular Events. N Engl J Med 2002; 347:1557-1565November 14, 2002. Available here.
2. Toth PP. The “Good Cholesterol”. Circulation.2005; 111: e89-e91. Available here.
3. Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. Executive Summary of The Third Report of The National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, And Treatment of High Blood Cholesterol In Adults (Adult Treatment Panel III). JAMA. 2001 May 16;285(19):2486-97. Available here.
4. Mosca L, Appel LJ, Benjamin EJ, Berra K, Chandra-Strobos N, Fabunmi RP, et al. Evidence-Based Guidelines for Cardiovascular Disease Prevention in Women. Circulation.2004; 109: 672-693. Available here.
5. American Diabetes Association. Dyslipidemia Management in Adults With Diabetes. Diabetes Care January 2004 vol. 27 no. suppl 1 s68-s71. Available here.
6. Centers for disease control and prevention. Cholesterol. Available here.
7. U.S. Department of Health and Human Services. Get Your Cholesterol Checked. Available here.
8. Hanukoglu I. Steroidogenic enzymes: structure, function, and role in regulation of steroid hormone biosynthesis. The Journal of Steroid Biochemistry and Molecular Biology. Volume 43, Issue 8, December 1992, Pages 779–804. Available here.
9. Lecerf JM, de Lorgeril M. Dietary cholesterol: from physiology to cardiovascular risk. British Journal of Nutrition / Volume 106 / Issue 01 / July 2011, pp 6-14. Available here.
10. Djoussé L, Gaziano JM. Dietary cholesterol and coronary artery disease: A systematic review. Current Atherosclerosis Reports. November 2009, 11:418. Available here.

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