hshawcross

What is cholesterol?

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Cholesterols are types of fat found in the blood. The liver produces sufficient cholesterol for the body’s requirements, but it can also be acquired from foods, particularly animal products, such as meat, egg yolks, butter, cheese and milk. Cholesterol is necessary for the body to function properly, as it is involved in the production of hormones and vitamin D, and in the digestive process.[1]

Cholesterol is not soluble in the blood and has to be transported through the bloodstream by carriers called lipoproteins (complexes of fatty acids and proteins).[1] There are two types of proteins that transport cholesterol to and from cells, high-density lipoproteins (HDL), and low-density lipoproteins (LDL). The levels of cholesterol bound to these lipoproteins in the bloodstream can be an important indicator of the risk of heart disease. A blood test commonly used by doctors to determine your ‘cholesterol level’ calculates the overall cholesterol level by adding HDL and LDL to 20% of the amount of triglyceride (another fat present in the blood).[2]

LDL is commonly known as ‘bad’ cholesterol. This is because it contributes to the formation of plaques within blood vessels, which are thick hard deposits that can clog arteries and decrease their flexibility, resulting in atherosclerosis.[3] If a blood clot forms in one of these narrowed arteries, it can result in a heart attack or a stroke.[1] Excess LDL can also contribute to peripheral artery disease, which is the result of plaque narrowing an artery that supplies blood to the extremities, such as the legs.[1]

HDL is known as ‘good’ cholesterol as it assists in the removal of LDL by acting as a scavenger, carrying LDL back to the liver where it is broken down and excreted.[4] 20% to 30% of cholesterol is carried by HDL.[4] [5] However, despite its beneficial actions, studies have shown that the level of HDL in the plasma may not reliably indicate the degree of reduction of LDL and so research into this area is continuing.[6] A satisfactory level of HDL can, however, decrease the risk of heart attack and stroke and, conversely, a level that is too low increases the risk.[7]

Triglycerides are another type of fat also present in the blood. They are also produced by the liver and are additionally found in oils, meat and dairy products. Their purpose is to provide energy to the body’s cells and tissues. When excess calories are ingested they are converted to triglycerides and stored as body fat and as fatty deposits within organs and tissues.[8] Like LDL, high levels of triglycerides are also associated with atherosclerosis,[9] and many people with diabetes or heart disease have high triglyceride levels within their blood. It is also common for people with high triglyceride levels to have a high ‘overall’ cholesterol level (i.e. a high LDL level and a low HDL level). One study has shown that a healthy lipid profile (i.e. low LDL, high HDL and low triglycerides), can reduce the risk of chronic heart disease by 71%.[10] Some common causes of elevated triglyceride levels include obesity, high alcohol consumption, cigarette smoking and a diet high in saturated fats.[11] Underlying diseases, e.g. poorly controlled diabetes, an underactive thyroid (hypothyroidism), kidney disease, and alcoholism,[11] and genetic disorders such as familial hypertriglyceridemia[12] can also cause increased levels of triglycerides.

The best way to maintain healthy cholesterol levels is by leading a healthy lifestyle: a varied and balanced diet, low in saturated fat and plenty of pesticide-free fruit and vegetables, in addition to sustaining a healthy weight. Exercise is another key factor in reducing or maintaining healthy cholesterol levels, although the exact mechanism for this is not yet clear.[13] Exercise is also beneficial in controlling weight. Smoking should be avoided and alcohol consumed in moderation; as well as increasing cholesterol levels, the adverse effects on health of both smoking and excess alcohol are well documented.


[1] NIH (2016) What is cholesterol? Retrieved May 2016 from, http://www.nhlbi.nih.gov/health/health-topics/topics/hbc

[2] Barter, P. et al. (2007) HDL Cholesterol, Very Low Levels of LDL Cholesterol, and Cardiovascular Events. The New England Journal of Medicine. 57. 1301-1310.

[3] Kyle, D. (2004) Understanding lipoproteins as transporters of cholesterol and other lipids. Advances in Physiology Education. 28(3). 105-106.

[4] Lee-Rueckert, M. et al. (2016) HDL functionality in reverse cholesterol transport - Challenges in translating data emerging from mouse models to human disease. Biochim Biophys Acta. 1861(7). 566-83.

[5] Schwartz, CC. et al. (2004) Lipoprotein cholesteryl ester production, transfer, and output in vivo in humans. J Lipid Res. 45(9). 1594-1607.

[6] Rothblat, G.H. et al. (2010) High-density lipoprotein heterogeneity and function in reverse cholesterol transport. Current Opinion in Lipidology, 21(3), 229-238.

[7] University of Pennsylvania. (2016) Fat and ketoacids, cholesterol, repair. Retrieved June, 2016, from https://www.med.upenn.edu/biocbiop/faculty/vanderkooi/chap7-9.pdf

[8] Toth, P. (2005) The “Good Cholesterol”. Circulation. 111(5). 89-91.

[9] Børge, G. et al. (2007) Nonfasting Triglycerides and Risk of Myocardial Infarction, Ischemic Heart Disease, and Death in Men and Women. Journal of the American Medical Association. 298(3). 299-308.

[10] Manninen, V. (1992) Joint effects of serum triglyceride and LDL cholesterol and HDL cholesterol concentrations on coronary heart disease risk in the Helsinki Heart Study Implications for treatment. Circulation. 85(1). 37-45.

[11] University of Colorado, Denver (2016) Cholesterol and Triglycerides Retrieved August, 2016, from http://www.ucdenver.edu/academics/colleges/medicalschool/departments/medicine/EndocrinologyMetabolismDiabetes/clinical/Documents/Lipid_Brochure.pdf

[12] NIH (2016) Familial hypertriglyceridemia.  Retrieved June, 2016, from https://www.nlm.nih.gov/medlineplus/ency/article/000397.htm

[13] Meissner, M. et al. (2010) Exercise enhances whole-body cholesterol turnover in mice. Med Sci in Sports Exercise. 42.1460-1468.

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Article does not explain clearly what cholesterol is and gives only general recommendations about healthy lifestyle. It doesn't report anything new. It is a well-known fact, that there are bad and good cholesterols, but what is the link between food we eat and level of cholesterols? What the link between sport and cholesterol, how it can help normilize cholesterol levels?

And why obesity is a cause of elevated level of triglicerides? I thought the more trigliceride, the more fat/obesity.

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On 5/30/2017 at 11:22 AM, gespalding said:

Article does not explain clearly what cholesterol is and gives only general recommendations about healthy lifestyle. It doesn't report anything new. It is a well-known fact, that there are bad and good cholesterols, but what is the link between food we eat and level of cholesterols? What the link between sport and cholesterol, how it can help normilize cholesterol levels?

And why obesity is a cause of elevated level of triglicerides? I thought the more trigliceride, the more fat/obesity.

gespalding, you want too much to squeeze into one article. If you want such a detailed information about the mechanisms by which food and sport affect cholesterol levels, use shall references used in this artcile and read scientific articles yourself or I suppose wait until whatishealthy.info writes one and we will all shortly be able to propose and vote for what we want to see written, fingers corssed the admin displayed message on voting will materialise as per said plan, this summer. I'm confident you'll find what you seeking here soon.

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On 16.11.2016 at 1:14 PM, hshawcross said:

Excess LDL can also contribute to peripheral artery disease, which is the result of plaque narrowing an artery that supplies blood to the extremities, such as the legs.[1]


Is it the cause of cold hands and feet? I thought cholesterol is linkd only with increased risk of heart attacks.

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On 6/1/2017 at 7:09 PM, deontimb said:

gespalding, you want too much to squeeze into one article. If you want such a detailed information about the mechanisms by which food and sport affect cholesterol levels, use shall references used in this artcile and read scientific articles yourself or I suppose wait until whatishealthy.info writes one and we will all shortly be able to propose and vote for what we want to see written, fingers corssed the admin displayed message on voting will materialise as per said plan, this summer. I'm confident you'll find what you seeking here soon.

deontimb, thank you for recommendation, but you are overestimating my abilities :) Scientific articles are too difficult to read, if you are not a specialist. Though, if I had a lot of spare time, I may dedicate it to reading original sources.

And that's the reason why I read this website. Scientific facts are provided in easy to comprehend form. But this article happens just scratching the surface, it's too simple. All these facts can be found in any non-professional article about cholesterol.

Indeed, to vote for what articles we want to see is a brilliant idea. It is exactly I am lacking on this website until I get to vote.

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My mother used to eat a lot of margarine, after she replaced butter with margarine fully as she found it more tasty. When her organism started signalling her that something is wrong - her blood preassure rised up - she went to doctor. Fortunately, the doctor advised her to cut out the margarine from her diet full stop, also he limited the amount of fat in general. In a matter of weaks her blood preassure bounced back and there is no margarine in our fridge anymore.

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On 5/30/2017 at 11:22 AM, gespalding said:

Article does not explain clearly what cholesterol is and gives only general recommendations about healthy lifestyle. It doesn't report anything new. It is a well-known fact, that there are bad and good cholesterols, but what is the link between food we eat and level of cholesterols? What the link between sport and cholesterol, how it can help normilize cholesterol levels?

And why obesity is a cause of elevated level of triglicerides? I thought the more trigliceride, the more fat/obesity.

The link between food and cholesterol level is very simple - the more fat you eat, the higher cholesterol level in blood you get, paricularly from high fat meet, cheese, unskimmed milk, margarine. Those are the most common products to spike your cholesterol. It's well-known information too, you shuld have educated to this level yourself by now.  

Regarding obesity and trigliceride levels, it is explainable too. As you may know obesity basically is a disturbed metabolism, i.e. food you consume can't be processed in a healthy way, something goes wrong and as a result some compounds are formed that are not supposed to be formed, e.g. triglicerides. I would say statement "the more triglicerides you get formed in your body, the more fat you become" suits only healthy people, but for obese it is much more complex.

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