Relationship of cholesterol and lipoproteins

Everything you need to know about cholesterol

relationship of cholesterol and lipoproteins

Two types of proteins called “lipoproteins” carry cholesterol in the blood: LDL and HDL. High LDL levels raise your risk for heart disease and. Cholesterol, triglycerides, and high-density lipoproteins are important constituents of the Obtained lipid values should be interpreted in relation to age and sex. Blood levels of total cholesterol, triglycerides and high-density lipoprotein A meta-analysis of prospective studies provided evidence of a link between Lp(a).

If you have other risk factors for heart disease, such as high blood pressure, diabetes, or if you smoke, keeping LDL-C low becomes even more important.

Diet, cholesterol and lipoproteins explained

Here you can see how LDL-C levels are interpreted: If your LDL-C is high, your doctor will probably suggest lifestyle changes. Quitting smoking will be helpful and so may eating whole grain, oatmeal, olive oil, beans, fruit, and vegetables. Most doctors will recommend eating less saturated fat, found primarily in meat and dairy products.

relationship of cholesterol and lipoproteins

Trans fats should be avoided. These fats are found in fried foods and many commercial products, such as cookies, crackers and snack cakes. Soluble fiber may help lower LDL-C. Soluble fiber is found in oats and oat bran, fruits, beans, lentils, and vegetables. Regular exercise is desirable.

Losing weight may be helpful. TAG is stripped from chylomicrons and VLDL through the action of lipoprotein lipase, an enzyme that is found on the surface of endothelial cells. This enzyme digests the TAG to fatty acids and monoglycerides, which can then diffuse into the cell to be oxidized, or in the case of an adipose cell, to be re-synthesized into TAG and stored in the cell. LDL delivers cholesterol to cells in the body. As VLDL particles are stripped of triacylglycerol, they become more dense.

These particles are remodeled at the liver and transformed into LDL. The function of LDL is to deliver cholesterol to cells, where it is used in membranes, or for the synthesis of steroid hormones blue pathway. Cells take up cholesterol by receptor-mediated endocytosis. Receptors are recycled to the cell surface, while hydrolysis in an endolysosome releases cholesterol for use in the cell. HDL is involved in reverse cholesterol transport.

relationship of cholesterol and lipoproteins

Excess cholesterol is eliminated from the body via the liver, which secretes cholesterol in bile or converts it to bile salts. The liver removes LDL and other lipoproteins from the circulation by receptor-mediated endocytosis.

Additionally, excess cholesterol from cells is brought back to the liver by HDL in a process known as reverse cholesterol transport green pathway. It travels in the circulation where it gathers cholesterol to form mature HDL, which then returns the cholesterol to the liver via various pathways. Disorders and Drug Treatments The link between cholesterol and heart disease was recognized through the study of individuals with familial hypercholesterolemia.

LDL & HDL: Good & Bad Cholesterol |

Individuals with this disorder have several-fold higher levels of circulating LDL due to a defect in the function of their LDL receptors. As well, because cholesterol cannot get into cells efficiently, there is no negative feedback suppression of cholesterol synthesis in the liver.

relationship of cholesterol and lipoproteins

Individuals with familial hypercholesterolemia may have strokes and heart attacks starting in their 30's. More common in the general population is dyslipidemia, which is the term that is used if lipid levels are outside the normal range. In a typical lipid profile, the fasting levels of total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides are determined.

relationship of cholesterol and lipoproteins

You can carry a certain amount of cholesterol in a high number of small LDLs, or you can carry the same amount in a low number of large LDLs. According to Peter, the main reason small LDL is bad, is because people who have mostly small LDL are more likely to have a higher total number of particles. It's not the small size that drives heart disease, but the fact that people with small particles tend to have a higher number of particles.

In other words, having a lot of small LDL is a marker for another more important problem.

LDL and HDL Cholesterol: "Bad" and "Good" Cholesterol

This is called discordance 8. The truth is, LDL-p is what really matters here. LDL-p can also be estimated by measuring another marker called ApoB.

HDL Cholesterol & Heart Disease Risk

LDL particle number is an "advanced" risk factor that many health professionals don't know about and is rarely measured. However, it may just be the strongest and most important risk factor there is for heart disease.

It has a direct role to play in the pathological process. What increases LDL cholesterol? Cholesterol is the "cargo" while the lipoproteins are the "boats. Therefore, anything that increases the number of LDL particles in your bloodstream will increase your risk of heart disease. Interestingly, refined carbs and sugar appear to be the primary culprits here.


This happened within as little as 2 weeks, using amounts of sugar that are similar to people's average consumption. If we take these markers into account, then heart disease is driven primarily by sugar and refined carbs, while a low-carb diet should directly reduce the risk. Whether this matters in the context of improvements in other markers blood pressureinflammation, blood sugar, triglycerides, HDL, for example is not known. Further reading If you want to delve even deeper into the science behind all of this, then Peter has written a comprehensive 9-part series on his blog, The Eating Academy.

The series is called "The Straight Dope on Cholesterol": Of course, even Peter's long series is a major simplification of a highly complicated subject. There are many other factors involved, including blood pressure, inflammation and oxidative stress, and most of these things are still being debated by scientists. The main reason is that I try to write articles that are understandable by a lay audience, and most people are familiar with these terms.

I may be contributing to confusion and misinformation by doing this and will consider my choice of words carefully in the future. Looking at the current state of the evidence, it becomes very clear that "cholesterol" is NOT the enemy.

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Heart disease is not a cholesterol disease, it is driven by the lipoproteins that carry cholesterol around. Video In the video below, Dr. Peter Attia, a medical doctor and one of the founders of the Nutrition Science Initiative, explains everything you need to know about diet, cholesterol and lipoproteins.