Everything You Need To Know About Cholesterol
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Cholesterol is a lipid belonging to the sterol family. Although it has had a bad press in recent years, cholesterol is an essential nutrient for the proper functioning of the body. 

It is mainly synthesized in the liver but can also be provided by food. Within the human body, cholesterol can be transported by different specific proteins including HDL cholesterol and LDL cholesterol. 

Including the levels of these two transporters within the body, the total cholesterol level, or cholesterolemia, is a value commonly measured to prevent or identify hypercholesterolemia.

Characteristics of cholesterol:

  • Lipids from the sterol family essential to the body
  • HDL and LDL cholesterol are two carriers of cholesterol
  • Mostly found in animal products
  • In excess, it increases the risk of cardiovascular accidents.

Why eat foods high in cholesterol?

Benefits and roles of cholesterol

Structural role of cholesterol

Cholesterol participates in the structure of cell membranes. It enters into the composition of the lipid bilayers of the membranes by inserting itself between the phospholipids. Cholesterol thus contributes to the stability and strengthening of the membranes.

Precursor role for the synthesis of hormones and vitamins

Cholesterol is a precursor to many molecules essential to the body. It participates for example in the synthesis:

  • steroid hormones such as aldosterone and cortisol;
  • sex steroid hormones such as estrogen, progesterone, and testosterone;
  • vitamin D.

Role of cholesterol in digestion

Cholesterol contributes to the synthesis of bile salts present in bile, a liquid necessary for the digestion of lipids.

What is total cholesterol?

The calculation of total cholesterol takes into account the HDL cholesterol level and the LDL cholesterol level. It is considered that it must be less than 2g/L. The analysis of total cholesterol is a good start but it is not enough, it is also important to know precisely the LDL and HDL levels as well as the total cholesterol/HDL ratio.

What is the HDL total cholesterol ratio?

The total/HDL cholesterol ratio is used to measure cardiovascular risk. It is used less and less. However, it is still considered that beyond 4.0 there is a significant arterial risk.

Foods High in Cholesterol

Cholesterol is found in foods of animal origin. Among them, here are 10 of the foods highest in cholesterol:

Food (per 100g)                                                Cholesterol content (in mg)              
Egg yolk1140
Duck foie gras1040
Lamb’s kidney588
Poultry liver530
Cod liver oil510
lamb liver410
veal kidney396

How to properly use cholesterol?

Use of cholesterol

If cholesterol is an essential nutrient for the proper functioning of the body, the human body has the ability to synthesize it. More than two-thirds of the cholesterol present in the body is synthesized by the liver. The rest comes from food sources like meat and eggs.

With few exceptions, it is believed that the body can produce enough cholesterol to meet its daily needs. During a cholesterol test, it is considered that the normal total cholesterol level in adults should be less than 2 g/L or 5 mmol/L. Nevertheless, this reference value can vary according to various parameters including age, sex, and medical history.

Analysis of cholesterol levels and normal values

The blood test makes it possible to know with precision the values ​​of the various lipids circulating in the blood. Here are the reference values ​​for the interpretation of blood tests.

Blood levels            Normal reference values 
Total cholesterol< 2g/L
LDL< 1.6g/L
HDL> 0,35g/L
Total cholesterol/HDL< 4

Cholesterol side effects

Total cholesterol too high: what are the risks?

Excess cholesterol, or hypercholesterolemia, is a major public health problem. It corresponds to a total cholesterol level greater than 2 g/l. Indeed, high cholesterol increases the risk of cardiovascular disease. 

In excess within the body, cholesterol tends to accumulate in the walls of the arteries, which leads to the formation of an atheroma plaque. This is called atherosclerosis, the consequences of which health can be serious. 

The passage of blood is disturbed, which increases the risk of high blood pressure. Rupture of an atheroma plaque can also lead to myocardial infarction, cerebrovascular accident (CVA), or obliterating arteriopathy of the lower limbs (PAD).

Total cholesterol level too low: what consequences?

Cholesterol deficiency, or hypocholesterolemia, is a rare phenomenon. It can be of genetic origin or can be secondary. This means that it can be the consequence of another phenomenon such as:

  • malnutrition;
  • cholesterol malabsorption;
  • pathology such as cancer;
  • a depressive state.

Interactions with other nutrients

Recent studies highlight the possible interactions between vitamin E and certain molecules used to treat hypercholesterolemia. 

Vitamin E is a powerful antioxidant often taken in the form of dietary supplements to fight cellular aging. However, this fat-soluble vitamin would significantly reduce the effectiveness of cholesterol-lowering drugs and partially cancel out the protective effect of these treatments on the cardiovascular system. 

It is therefore recommended that you seek the advice of a doctor before taking vitamin E if you suffer from hypercholesterolemia.

Chemical properties

The molecular formula of cholesterol is C27H46O, and its molar mass is 386.6535 g/mol. Cholesterol is a lipid belonging to the sterol family and plays a central role in many metabolic reactions.

The cholesterol molecule is bipolar, only the hydrophilic head has an OH molecule. If this OH molecule is esterified by a fatty acid, the cholesterol molecule then becomes totally insoluble in water. It is in this esterified form, or steroids, that cholesterol circulates in the liver, brain, and marrow.

We wrongly speak of “good” or “bad” cholesterol to define HDL cholesterol and LDL cholesterol. However, there is indeed only one molecule of cholesterol. HDL and LDL are the only carriers of this unique molecule. LDL transports cholesterol from the liver to tissues, promoting deposits in the arteries, while HDL transports cholesterol from tissues to the liver.


Nutrient history

It was by analyzing gallstones that F. Poulletier first discovered the existence of cholesterol in 1758. However, it was not until the 1950s that the role of cholesterol, and more particularly LDL, was recognized in the occurrence of cardiovascular diseases.

It was only after the Second World War that A. Keys will shed light on the role of diet in preventing high cholesterol. It is the origin of the very famous Mediterranean diet.

It will be necessary to wait until 1973 for the biochemist A. Endo to discover the first statin. Since then, statins have been used on a very large scale to limit the cardiovascular risks associated with hypercholesterolemia throughout the world.

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