Cholesterol chemical properties. Cholesterol: what is it? The process of cholesterol formation

is a vital compound for the body. It is a substrate for the hormone progesterone, estrogen, testosterone, adrenal hormones (aldosterone, cortisol), participates in one of the directions of vitamin D metabolism, and is also used to build membranes and cell walls.

Cholesterol, from the point of view of biochemistry, is an organic lipophilic alcohol that does not dissolve in water. Consider what is characteristic of the chemical formula of cholesterol and what features and stages are isolated in the process of its biosynthesis.

Cholesterol belongs to the group of steroids. It is one of the main steroids in the human macroorganism, determines the activity of lipid metabolism. In its structure, it is a solid crystalline colorless substance that does not dissolve in water. The laboratory unit of measurement in peripheral blood is mmol/l.

Chemical the formula (it is also the gross formula) of cholesterol is C27H46O.

The molecular weight is about 387 g/mol.

Structural the form looks like this:

Structural formula of cholesterol with the numbering of atoms in the molecule

One of the main features of the cholesterol molecule is the ability to bind with other compounds, forming complexes of molecules. Such compounds can be acids, amines, proteins, cholecalciferol (vitamin D3 precursor), salts, and others. This property is due to the characteristic structure of the cholesterol molecule and its high activity in biochemical processes.

biosynthesis of cholesterol

All cholesterol in the human macroorganism is divided into exogenous and endogenous. Exogenous is about 20% of the total and enters the body with food. Endogenous cholesterol is synthesized directly in the body. Its production takes place simultaneously in two locations. About 15% of the substance is formed in the intestine by specific cells by enterocytes, and about 50% of endogenous cholesterol is produced in the liver, where it subsequently binds to proteins, forms complexes in the form of lipoproteins and enters the peripheral bloodstream. A small part is also sent to the synthesis of triglycerides - esters of fatty acids and glycerol, which combine with cholesterol.

Cholesterol synthesis is a complex and energy-intensive process. More than 30 consecutive lipid transformation reactions are required to result in a cholesterol molecule. Schematically, all these transformations can be grouped into six stages in the process of cholesterol synthesis.

1. Biosynthesis of mevalonate. Consists of three reactions. The first two of them are ketogenesis reactions, and the third reaction is catalyzed by the enzyme HMG-SCoA reductase, under the action of which the first cholesterol precursor, mevalonic acid, is formed. The mechanism of action of most lipid-lowering drugs, especially statins, is directed precisely at this link in biosynthesis. By influencing the enzymatic activity of reductases, cholesterol transformation can be partially controlled.
2. Biosynthesis of isopentenyl pyrophosphate. Three phosphate residues are attached to the resulting mevalonic acid. After that, it goes through the processes of decarboxylation and dehydrogenation.
3. The third step is the fusion of three isopentenyl pyrophosphates, which are converted into farnesyl diphosphate.
4. From 2 residues of farnesyl diphosphate, a new molecule is formed - squalene.
5. Linear squalene undergoes a series of cyclization reactions and is transformed into lanosterol.
6. Excess methyl groups are cleaved from lanosterol, the compound goes through an isomerization and reduction stage, as a result of which a cholesterol molecule is formed.

In addition to the active enzyme HMG-CoA reductase, biosynthesis reactions involve insulin, glucagon, adrenaline, and a special carrier protein that binds metabolites at different stages.

Cholesterol esters

Esterification of cholesterol is the process of binding fatty acids to it. It is launched either to transfer the cholesterol molecule, or to transform it into an active form.

In these transformations, an important role is played by lecithin- it attaches to the cholesterol molecule and forms esters under the action of the enzyme lecithin-cholesterol-acyl transferase lysoleucine and cholesterol. Thus, the esterification reaction is a process aimed at reducing the amount of free cholesterol in the bloodstream. The resulting esters are tropic to "good" high-density lipoproteins and easily attach to them. The formation of cholesterol esters is part of a protective anti-atherosclerotic mechanism.

Cholesterol is a very important compound for the macroorganism, which takes part not only in lipid metabolism, but also in the processes of transformation of biologically active substances and the synthesis of cell membranes. The molecule of this substance goes through a complex cycle of transformations of more than 30 reactions, which are regulated and controlled by the enzymatic and humoral systems.

Changes in one of the links of biosynthesis can become an indicator of pathology in the internal organs and systems - the liver, thyroid and pancreas. Preventive examinations and screening lipidograms should be carried out in order to identify the pathological process in time.

The functions of cholesterol in the body have long been a subject of scientific interest. Scientists' research is aimed at preventing atherosclerosis, a dangerous disease in the development of which cholesterol plays one of the main roles.

Despite the abundance of information, many people still consider cholesterol to be harmful substances. In fact, cholesterol helps maintain health, performing an important role in the body - ensuring metabolic processes.

The body's need for cholesterol is low. Only 10% of people have an increased concentration of the substance. Previously, there was an opinion that all cholesterol is harmful and leads to atherosclerosis.

High cholesterol is bad for the arteries, but its deficiency leads to increased fragility of the vessels. In this case, the damaged areas strengthen cholesterol patches.

Main functions of cholesterol

In the right concentration, cholesterol provides many life processes:

1. Maintains the shape and function of cell membranes: increases strength, regulates permeability. The membrane performs a barrier function between the contents of the cells and the external environment. At the same time, this semi-permeable partition is capable of passing water molecules and certain substances dissolved in it. Cell membranes are 95% built from lipoproteins, which include glyco-, phospholipids, cholesterol. Providing a stabilizing effect, it resists the damaging effects of free radicals.
2. Provides transportation of useful and harmful elements, regulation of the activity of enzymes that greatly accelerate biochemical reactions.
3. Takes part in the synthesis of sex hormones, maintains a normal hormonal background.
4. Participates in the synthesis of bile acids.
5. Supports the structure and growth of fetal cells. For bearing a fetus during pregnancy, the female body requires an increased amount of cholesterol. Mother's milk rich in cholesterol has a positive effect on the health of the child.
6. Ensures the normal functioning of the brain, protects against Alzheimer's disease. Scientific studies show a direct effect of cholesterol on mental performance.

The human body contains 140-350 g of cholesterol, 90% of which is in the tissues, and 10% in the blood. Insoluble in water, cholesterol dissolves in fatty media. It is transported to all tissues of the body by lipoproteins - complexes of proteins and fats.

There are several types of lipoprotein complexes of different density that determine the structure of cholesterol in the body:

• LDL - low density - 70%;
• VLDL - very low density - 9-10%;
• HDL - high density - 20-24%.

Low-density lipoproteins are called bad or bad cholesterol. Their source is only animal fats. LDL provides the delivery of cholesterol to cells that need it, replenish them with vitamins, and have a neutralizing effect on toxins.

Our body needs bad cholesterol, which supports the functioning of the immune system, including protection against cancer.

At the same time, LDL is the cause of the appearance of plaques deposited on the walls of blood vessels that can cause their blockage (atheroma).

As a result, atherosclerosis and a number of concomitant pathologies develop: peripheral arterial disease, ischemic attacks, angina pectoris, stroke, heart attack. The ailments caused by atheroma lead to poor health and most often cause death.

The structure of HDL is different from LDL. They have an anti-atherosclerotic effect, removing LDL from the cell walls and delivering them to the liver for processing and excretion from the body. As a result, the thickness of the plaque decreases, and the risk of atherosclerosis is reduced.

Obesity, diabetes mellitus, hepatosis of the liver are factors that increase the level of bad cholesterol and reduce the level of good.

Eating certain foods helps to optimize the ratio of cholesterol components in the blood:

• Carrots, Jerusalem artichoke, celery, cabbage, beets, bran, greens, citrus fruits, pears, apples containing insoluble fiber;
• Phytosterols that lower LDL levels: cereals, pumpkin, eggplant, zucchini, ginger, hibiscus, sesame, strawberries;
• legumes;
• Sea fish, fish oil, corn, olive, mustard oil;
• Red rice;
• Avocado and oil of this fruit;
• Onion garlic.

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Everything you need to know about triglycerides

Fats are an important part of our life from a biological point of view, since we get a large share of energy from them, which we then expend over time. But everything is good in moderation, and obese people will confirm this. Where does obesity come from? What causes dietary fats to be deposited in different parts of the body? Of course, hypodynamia and overeating play a significant role. But there are also biochemical reasons that lie in the word "triglycerides". So what are triglycerides? Let's try to figure it out.

Functions

And it will not be easy to figure it out, because chemists and biologists have different opinions about triglycerides. On two points, their opinions agree: this is the "formula of triglyceride" and "the structure of triglyceride." As for functions, chemists tend to completely ignore the complex biological role that these substances play in the body.

Biologists, on the other hand, are not particularly interested in the "personal qualities" of triglycerides, and consider them as part of the extremely complex metabolism of fats and energy in the body.

Such divergent views are partly due to the inflexibility of chemical terminology: when lipids (fats in the broad sense) were first discovered, they were described too strictly and unambiguously. Over time, lipids were found that did not fit the old definition, and chemists had to rush to come up with clarifications and exceptions.

Confused in the chaos of definitions, biologists began to consider lipids (including TH) as part of metabolism, ignoring chemical terminology.

Let us briefly list the terms that are needed to understand the role of triglycerides in the body:

• Lipids are fats in the broad sense of the word or fat-like substances. Present in all living cells.
• Triglycerides are simple lipids, among all fats, they are the main source of nutrition for cells. Synonym: "common fats". Subdivided into: short chain TG, medium chain triglycerides, long chain TG.
• Lipoproteins are proteins that contain lipids. They are divided into high-density lipoproteins (“good” lipoproteins) and low-density lipoproteins (“bad” fats).
• Cholesterol is a fat-soluble alcohol. Normally, it is extremely important for the normal functioning of cell membranes, while in excess it is deposited on the inner walls of blood vessels in the form of crystals.

So, triglycerides are a common fat that comes to us with food and performs several functions:

1. It is spent on the current energy needs of the body.
2. It is deposited in the form of fat reserves.
3. Transforms into lipoproteins.

There are no special explanations for the first point. According to the second, the following can be noted: a person has 3 main sources of energy - proteins, fats and carbohydrates. Why fats are deposited in peripheral tissues? First, 1 gram of fat gives a person as much energy as 2 grams of carbohydrates or proteins will give.

Secondly, fat does not conduct heat well, therefore, in the cold season, due to body fat, a person loses less heat (which is also energy).

The third point, transformation into lipoproteins, deserves some attention. But first, let’s talk about the difference between short, medium, and long chain TGs. In fact, their general formula is the same, but the difference lies in the number of “fat blocks” per molecule. Short-chain triglycerides have 4-6 of them, long-chain triglycerides have about 20. So, the more fat blocks per fat molecule involved in the synthesis of lipoprotein, the lower the density of this lipoprotein itself.

What is the difference between high and low density lipoproteins? The structure of HDL is arranged in such a way that these molecules carry cholesterol from peripheral tissues to the central bloodstream, where this cholesterol is consumed according to the situation.

LDL, on the other hand, does the opposite: they transfer cholesterol from the general circulation to peripheral tissues and small vessels, where (with an excess of LDL) crystalline deposits form.

It is very easy to get confused in the metabolism (even doctors sometimes forget what comes from what and goes into what), so we will provide a brief summary of all of the above:

1. fat in the form of TG with food enters the body;
2. part goes to current needs, part - to body fat, part - to the production of lipoproteins;
3. the longer the triglyceride chain, the more fat the body needs to distribute;
4. the more fat you need to distribute, the more goes into reserves and the more low-density lipoprotein is produced;
5. the more low density lipoproteins, the more cholesterol is in small vessels.

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Blood test

Triglycerides in the blood are determined using a biochemical blood test. This blood test should be done according to standard recommendations: on an empty stomach, in the morning, 2 days before the test, you need to eat the same as usual.

The triglycerides in the analysis are shown as mixed, without division by chain length (because this is very problematic from a technical point of view).

Scientific studies of the relationship between triglyceride levels and body condition

Research on TH began in 1950, and since then the amount of data has been steadily increasing. For convenience, the studies are divided into subcategories: triglyceride studies, triglycerides and nutrition, medium chain triglycerides as therapy.

Triglyceride Research

As mentioned above, TH was found in the blood in the middle of the last century, and in the next few decades, the primary task of scientists was to find out what kind of fat it is and what it is responsible for.

By and large, the results of these studies are described in the "More about triglycerides and their functions" section of this article. Short chain MCTs (Medium Chain Triglycerides), long chain MCTs and medium chain TGs were detected. Much attention has been paid to their lipoprotein conversion property, as a result of which it has been found that an excess of fatty foods in food provokes hypertriglyceridemia, which causes the production of large amounts of low-density lipoproteins, which lead to atherosclerosis and heart attacks.

Thus, a blood test for triglycerides has become a tool for the early diagnosis of atherosclerosis.

Triglycerides and nutrition

Triglycerides in food have become a separate branch of research, because changing your diet is the best (and only) way to normalize this blood parameter.

The first of the interesting facts was that in order to normalize the level of fat, you need to reduce the consumption of carbohydrates. The same sugar, for example, does not contain fat, but the more sugar in the daily diet, the more energy the body receives from it.

Fats, which in a normal case would go to the current needs of the body, remain unused and go "in reserve".

The second interesting fact is that alcohol increases the level of fats in the blood. This is due to the fact that alcoholic beverages heavily burden the liver, and it does not have time to process fats into energy. Therefore, frequent alcohol consumption leads to obesity.

And finally, "good" and "bad" foods. The most important discovery (and not only for TG) was the discovery of vitamin D, now called "Omega-3". By itself, this vitamin does nothing for a person, but, once in the blood, it accelerates the absorption of all other vitamins, as well as proteins, fats and carbohydrates. This vitamin is found in fish bones and joints, so getting it from food is not very easy. If you need to correct the balance of triglycerides (and other metabolic participants), it is better to drink a course of vitamin D.

Other food discoveries can be found in any nutrition guide. Long-chain TGs predominate in fried foods, fast food, and animal fats.

Short and medium chain triglycerides predominate in plant foods and oils.

Medium chain triglycerides as therapy

These TGs are of great interest to scientists because of their balance. The predominance of short-chain TG in the diet leads to malnutrition and dystrophy, while long-chain TG leads to atherosclerosis and obesity.

Medium chain triglycerides lie between these two extremes: they provide enough energy and do not lead to weight gain. Therefore, doctors began to develop individual diets with a predominance of "average" TGs, and empirical studies have shown that such diets work.

Another use of medium-length triglycerides is in situations where the remaining triglycerides cannot be absorbed due to intestinal or liver pathologies (most often genetic).

For reasons not fully understood, a diet high in medium-chain triglycerides (more than 70% of total triglycerides) reduces the number of epileptic seizures in patients with epilepsy.

And finally, medium-chain TGs work effectively when the patient is unable to eat independently (coma). Increasing these triglycerides in the "diet" in these patients reduces the risk of long-term complications from parenteral nutrition.

So, what are "triglycerides" in a biochemical blood test? This is the total fat that enters the body with food. TG are included in a more extensive system of metabolism and energy production, evenly distributed throughout it. An increase or decrease in triglyceride levels is an extremely alarming sign, indicating either poor nutrition or metabolic problems.

How and why cholesterol is produced in the liver

The human body is a unique complex machine, which sometimes amazes with its capabilities. The biochemistry of the processes is so unusual that sometimes one cannot even imagine them. The liver is responsible for many processes, the production of cholesterol is one of its most important functions, the synthesis of steroid hormones, vitamin D, the transport of certain substances, and more depend on it. But how does it happen? Where does cholesterol come from in the liver, how is it synthesized, and what happens in the body when it is broken?

Substance production

Many products - meat, eggs, oils, convenience foods and even fast food - contain cholesterol, and a person consumes them daily. It would seem that these sources can fully meet the needs of the body, why then does the liver produce its own low density lipoprotein (LDL)?

Most often, cholesterol, which contains food "sources", has a low density and is called "bad", because due to a violation of the structure, the body cannot use it for synthesis or transport, so it settles in the form of atherosclerotic plaques on the walls of blood vessels or in the internal their parts.

The liver, on the other hand, “takes care” of health, it also produces cholesterol, which has a normal density, but it filters out its “harmful” analogue from the blood and gradually removes it from the body in the form of bile. This factor prevents the rapid development of atherosclerotic plaques.

biosynthesis of cholesterol

The formation of cholesterol molecules in the liver is an interesting process, which is not difficult to understand. It occurs in cells - hepatocytes. They have a well-developed endoplasmic reticulum - a cell organelle responsible for the production of fatty and carbohydrate substances, as well as their modification. It is not necessary to delve into the jungle of biosynthesis, but you should proceed to the main points of the process.

There is a phased synthesis of such compounds:

• mevalonate;
• isopentenyl pyrophosphate;
• squalene;
• lanosterol;
• and finally cholesterol.

Synthesis of mevalonate

For the synthesis of mevalonate, the body needs a lot of glucose, which is found in sweet foods, cereals. Each sugar molecule is broken down in the body under the influence of enzymes to 2 molecules of acetyl-CoA. After that, acetoacetyltransferase enters the reaction, which converts the last product into acetoyl-CoA. From this compound, through other complex reactions, mevalonate is eventually formed.

Isopentenyl pyrophosphate

When enough mevalonate is produced in the endoplasmic reticulum of hepatocytes, the synthesis of isopentenyl pyrophosphate begins. To do this, mevalonate is phosphorylated - it gives up its phosphate to several molecules of ATP - a nucleotide, which is the universal energy storage of the body.

Squalene

By successive condensations (water release) of isopentenyl pyrophosphate, a squalene molecule is formed. If in the past reaction the cell spends the energy of ATP, then for the synthesis of squalene it uses NADH - another source of energy.

Lanosterol

The penultimate reaction in the chain of creation of cholesterol by the liver is the production of lanosterol. This occurs when water is removed from the lanosterol molecule, after which the molecular form of the compound, instead of being unfolded, becomes cyclic. Here, NADPH becomes the energy donor for the reaction.

Cholesterol

The process of converting lanosterol to cholesterol occurs in the membranes of the endoplasmic reticulum of the hepatocyte. The molecule of the first substance, through several modifications, acquires a double bond in the carbon chain. This requires a lot of energy, the donors of which are NADPH molecules. After various transformer enzymes “work” on lanosterol derivatives, cholesterol is formed.

The path of synthesis in the body is complex, it takes place in 5 stages, which are controlled by various enzymes, energy donors and other factors. For example, the activity of some reaction catalysts is influenced by thyroid hormones and insulin.

How the body uses the substance

Synthesized cholesterol is necessary for very important processes. Some of its main functions:

• synthesis of steroid hormones;
• and vitamin D;
• transport Q10.

Hormone production

Steroids are: corticosteroids, glucocorticoids, mineralcorticoids and others that regulate metabolic processes, active substances, as well as female and male sex hormones. All of them are no longer formed in the liver, but in the adrenal glands. Cholesterol gets there due to the fact that all organs are connected by a network of blood vessels through which blood delivers it.

Synthesis of vitamin D

There is a lot of cholesterol in skin cells, since vitamin D is produced from it under the influence of ultraviolet radiation, which regulates the absorption of calcium in the body. LDL is transported to the epidermis from the liver, but some of it is synthesized in the cells of the skin.

Transport Q10

If we talk about the molecular function of cholesterol, then it is worth mentioning the transport of Q10. This enzyme protects membranes from the destructive action of enzymes. A lot of Q10 is synthesized in certain structures, and then they are released into the bloodstream. On its own, it cannot penetrate other cells, so there is a need for a transporter. Responsibility for the transport of Q10 takes on cholesterol, "dragging" the enzyme inside.

Exchange disorder

What happens if cholesterol synthesis changes? The consequences of the deviation depend on whether the reaction has shifted towards a lack or excess of the produced molecules.

Lack of cholesterol

Due to diabetes, thyroid disorders, heart failure, or a genetic predisposition, the body can produce less LDL than it should. When this happens in the human body, serious diseases appear:

• lack of sex and other steroid hormones;
• children develop rickets as a result of not absorbing calcium;
• premature aging and cell death due to the destruction of their membranes without Q10;
• weight loss with insufficient breakdown of fats;
• immune suppression;
• there are pains in the muscles and heart.

You can solve the problem of lack of cholesterol if you follow a diet whose menu contains foods with healthy cholesterol (eggs, lean meat, dairy products, vegetable oils, fish), as well as in the treatment of diseases that caused abnormal LDL production in the liver.

Excess cholesterol

If a person has too much cholesterol, then his health is also at risk. The reason for this violation is:

• hepatitis and cirrhosis (the liver cannot dispose of excess cholesterol in time);
• excess weight;
• lipid metabolism disorders;
• chronic inflammatory processes.

With the accumulation of cholesterol, atherosclerotic plaques are formed inside the vessels, a lot of bile is produced, which does not have time to leave the gallbladder and forms stones there, and the work of the heart and nervous system also suffers. If this condition is not treated, myocardial infarction, stroke, and so on will soon develop.

Conclusion

Cholesterol synthesis by the liver is a complex energy-consuming process that takes place daily inside the liver cells. The body produces its own high-density lipoproteins so that the vessels do not become covered with cholesterol plaques, which are the site of deposition of harmful cholesterol from food. If this synthesis is disturbed, then atherosclerosis progresses.

Cholesterol in modern man is considered the main enemy, although a few decades ago it was not given such great importance. Being carried away by new, not so long ago invented products, often in their composition very far from those that our ancestors used, ignoring the diet, a person often does not understand that the main share of the blame for the excessive accumulation of cholesterol and its harmful fractions lies with himself. The “crazy” rhythm of life does not help to fight cholesterol, predisposing to disruption of metabolic processes and the deposition of excess fat-like substances on the walls of arterial vessels.

What is good and bad about it?

Constantly "scoldling" this substance, the people forget that it is necessary for a person, since it brings a lot of benefits. What is good about cholesterol and why it should not be excluded from our lives? So, its best features:

• A secondary monohydric alcohol, a fat-like substance called cholesterol, in the free state, together with phospholipids, is part of the lipid structure of cell membranes and ensures their stability.
• Cholesterol in the human body, breaking down, serves as a source of formation of hormones of the adrenal cortex (corticosteroids), vitamin D 3 and bile acids, which play the role of fat emulsifiers, that is, it is a precursor of highly active biological substances.

But in other way Cholesterol can be the cause of various troubles:

Patients often discuss the bad properties of cholesterol among themselves, share experiences and recipes on how to lower it, but this can be useless if everything is done at random. To slightly reduce the level of cholesterol in the blood (again - what?) Diet, folk remedies and a new lifestyle aimed at improving health will help. To successfully resolve the issue, it is necessary not only to take total cholesterol as a basis in order to change its values, it is necessary to figure out which of the fractions should be lowered so that the others themselves return to normal.

How to decipher the analysis?

The norm of cholesterol in the blood should not exceed 5.2 mmol / l, however, even a concentration value approaching 5.0 cannot give complete confidence that everything is good in a person, since the content of total cholesterol is not an absolutely reliable sign of well-being. The normal level of cholesterol in a certain proportion is made up of different indicators, which cannot be determined without a special analysis called the lipid spectrum.

The composition of LDL cholesterol (atherogenic lipoprotein), in addition to LDL, includes very low density lipoproteins (VLDL) and "remnants" (the so-called residues from the reaction of the transition of VLDL to LDL). All this may seem very complicated, however, if you look at it, then anyone interested can master the decoding of the lipid spectrum.

Usually, when conducting biochemical analyzes for cholesterol and its fractions, the following are isolated:

• Total cholesterol (normal up to 5.2 mmol / l or less than 200 mg / dl).
• The main "vehicle" of cholesterol esters is low-density lipoprotein (LDL). They in a healthy person have their 60-65% of the total (or the level of cholesterol LDL (LDL + VLDL) does not exceed 3.37 mmol/l). In those patients who have already been affected by atherosclerosis, LDL-C values ​​may increase markedly, which occurs due to a decrease in the content of anti-atherogenic lipoproteins, that is, this indicator is more informative in relation to atherosclerosis than the level of total cholesterol in the blood.
• high density lipoproteins(HDL cholesterol or HDL cholesterol), which normally women should have more than 1.68 mmol/l(for men, the lower limit is different - higher 1.3 mmol/l). In other sources, you can find somewhat different numbers (in women - above 1.9 mmol / l or 500-600 mg / l, in men - above 1.6 or 400-500 mg / l), it depends on the characteristics of the reagents and the methodology carrying out the reaction. If the level of HDL cholesterol becomes less than acceptable values, they cannot fully protect the vessels.
• An indicator such as atherogenic coefficient, which indicates the degree of development of the atherosclerotic process, but is not the main diagnostic criterion, is calculated by the formula: CA \u003d (OH - HDL-C) : HDL-C, its normal values ​​range from 2-3.

Cholesterol tests do not require the isolation of all fractions separately. For example, VLDL can be easily calculated from the concentration using the formula (VLDL-C = TG: 2.2) or subtract the sum of high and very low density lipoproteins from total cholesterol and get LDL-C. Perhaps these calculations will not seem interesting to the reader, because they are given only for informational purposes (to have an idea about the components of the lipid spectrum). In any case, the doctor is engaged in decoding, he also makes the necessary calculations for the positions of interest to him.

More about blood cholesterol levels

Perhaps readers have come across information that the norm of cholesterol in the blood is up to 7.8 mmol / l. Then they can imagine what a cardiologist will say when they see such an analysis. Definitely - he will prescribe the entire lipid spectrum. Therefore, once again: a normal cholesterol level is an indicator up to 5.2 mmol/l(recommended values), borderline up to 6.5 mmol / l (risk of development!), and everything above, respectively, elevated (cholesterol is dangerous in high numbers and, probably, the atherosclerotic process is in full swing).

Thus, the concentration of total cholesterol in the range of 5.2 - 6.5 mmol / l is the basis for a test that determines the level of cholesterol of anti-atherogenic lipoproteins (HDL-C). Analysis for cholesterol should be carried out after 2 to 4 weeks without giving up the diet and the use of medications, testing is repeated every 3 months.

About the lower bound

Everyone knows and talks about high cholesterol, trying to reduce it by all available means, but almost never take into account the lower limit of normal. It's like she doesn't exist. Meanwhile, low blood cholesterol can be present and accompany quite serious conditions:

1. Prolonged fasting until exhaustion.
2. Neoplastic processes (depletion of a person and the absorption of cholesterol from his blood by a malignant neoplasm).
3. Severe liver damage (the last stage of cirrhosis, dystrophic changes and infectious lesions of the parenchyma).
4. Lung diseases (tuberculosis, sarcoidosis).
5. Hyperthyroidism.
6. (megaloblastic, thalassemia).
7. Damage to the CNS (central nervous system).
8. Prolonged fever.
9. Typhus.
10. Burns with significant damage to the skin.
11. Inflammatory processes in soft tissues with suppuration.
12. Sepsis.

As for the fractions of cholesterol, they also have lower limits. For example, lowering high-density lipoprotein cholesterol levels beyond 0.9 mmol/l (antiatherogenic) accompanies risk factors for coronary artery disease(physical inactivity, bad habits, overweight,), that is, it is clear that people develop a tendency, because their vessels are not protected, because HDL becomes unacceptably low.

Low blood cholesterol, which is low-density lipoprotein (LDL), is observed in the same pathological conditions as total cholesterol (wasting, tumors, severe diseases of the liver, lungs, anemia, etc.).

Cholesterol in the blood is elevated

First, about the causes of high cholesterol, although, probably, they have already been known to everyone for a long time:

• Our food and above all - products of animal origin (meat, whole fat milk, eggs, cheeses of various varieties), containing saturated fatty acids and cholesterol. The craze for chips and all sorts of fast, tasty, satisfying fast foods saturated with various trans fats also does not bode well. Conclusion: such cholesterol is dangerous and its consumption should be avoided.
• Body mass- excess increases the level of triglycerides and reduces the concentration of high-density lipoproteins (anti-atherogenic).
• Physical activity. Physical inactivity is a risk factor.
• Age over 50 and male gender.
• Heredity. Sometimes high cholesterol is a family problem.
• Smoking not that it greatly increased total cholesterol, but it well reduces the level of the protective fraction (Cholesterol - HDL).
• Taking certain medications(hormones, diuretics, beta-blockers).

Thus, it is not difficult to guess to whom the cholesterol test is prescribed in the first place.

Diseases with high cholesterol

Since so much has been said about the dangers of high cholesterol and the origin of such a phenomenon, then it would probably be useful to note under what circumstances this figure will increase, since they are also to some extent can cause high cholesterol in the blood:

1. Hereditary disorders of metabolic processes (family variants due to metabolic disorders). As a rule, these are severe forms, characterized by early manifestation and special resistance to therapeutic measures;
2. Coronary artery disease;
3. Various pathologies of the liver (hepatitis, jaundice of non-hepatic origin, obstructive jaundice, primary biliary cirrhosis);
4. Severe kidney disease with renal failure and edema:
5. Hypothyroidism (hypothyroidism);
6. Inflammatory and neoplastic diseases of the pancreas (pancreatitis, cancer);
7. (it is difficult to imagine a diabetic without high cholesterol - this is, in general, a rarity);
8. Pathological conditions of the pituitary gland with a decrease in the production of somatotropin;
9. Obesity;
10. Alcoholism (in alcoholics who drink, but do not eat, cholesterol is elevated, but atherosclerosis does not develop often);
11. Pregnancy (the condition is temporary, the body will fix everything after the expiration date, but the diet and other prescriptions for a pregnant woman will not interfere).

Of course, in such situations, patients no longer think about how to lower cholesterol, all efforts are aimed at combating the underlying disease. Well, those who are still not so bad have a chance to save their vessels, but it will not work to return them to their original state.

Fight against cholesterol

As soon as a person learned about his problems in the lipid spectrum, studied the literature on the topic, listened to the recommendations of doctors and just knowledgeable people, his first desire is to lower the level of this harmful substance, that is, to start treating high cholesterol.

The most impatient people ask to immediately prescribe them medicines, others prefer to do without "chemistry". It should be noted that the opponents of drugs are right in many respects - you need to change yourself. To do this, patients switch to and become a little vegetarian in order to free their blood from “bad” components and prevent new ones from getting into fatty foods.

Food and cholesterol:

A person changes his way of thinking, he tries to move more, visits the pool, prefers outdoor activities, removes bad habits. For some people, the desire to lower cholesterol becomes the meaning of life, and they begin to actively engage in their health. And it is right!

What is needed for success?

Among other things, in search of the most effective remedy for cholesterol problems, many people are addicted to those formations that have already settled on the walls of the arteries and damage them in some places. Cholesterol is dangerous in a certain form (Cholesterol - LDL, Cholesterol - VLDL) and its harmfulness lies in the fact that it contributes to the formation of atherosclerotic plaques on the walls of arterial vessels. Such activities (the fight against plaques) undoubtedly have a positive effect in terms of general cleansing, preventing excessive accumulation of harmful substances, and stopping the development of the atherosclerotic process. However, with regard to the removal of cholesterol plaques, the reader will have to be somewhat upset here. Once formed, they never go anywhere. The main thing is to prevent the formation of new ones, and this will already be a success.

When things go too far, folk remedies stop working, and the diet no longer helps, the doctor prescribes cholesterol-lowering drugs (most likely, these will be statins).

Difficult treatment

(lovastatin, fluvastatin, pravastatin, etc.), reducing the level of cholesterol produced by the patient's liver, reduce the risk of development (ischemic stroke) and, thereby, help the patient avoid death from this pathology. In addition, there are combined statins (Vitorin, Advicor, Kaduet), which not only reduce the amount of cholesterol produced in the body, but also perform other functions, for example, lower blood pressure, affect the ratio of "bad" and "good" cholesterol.

The likelihood of receiving drug therapy immediately after determining the lipid spectrum increases at patients with diabetes mellitus, arterial hypertension, problems with coronary vessels, since the risk of getting myocardial infarction is much higher.

In no case should you follow the advice of acquaintances, the World Wide Web and other dubious sources. Medicines of this group are prescribed only by a doctor! Statins are not always combined with other drugs that the patient is forced to constantly take in the presence of chronic diseases, so his independence will be absolutely inappropriate. In addition, during the treatment of high cholesterol, the doctor continues to monitor the patient's condition, monitors the lipid spectrum, supplements or cancels therapy.

Who is first in line for analysis?

It is hardly possible to expect a lipid spectrum in the list of priority biochemical studies used in pediatrics. An analysis for cholesterol is usually taken by people with some life experience, often male and well-fed physique, burdened by the presence of risk factors and early manifestations of the atherosclerotic process. Reasons for conducting appropriate tests include:

• Cardiovascular diseases, and first of all - coronary heart disease (patients with coronary artery disease are more aware of the lipid profile than others);
• Arterial hypertension;
• Increased content; (hyperuricemia);
• The presence of bad habits in the form of smoking;
• Obesity;
• The use of corticosteroid hormones, diuretics, beta-blockers.
• Treatment with cholesterol-lowering drugs (statins).

An analysis for cholesterol is taken on an empty stomach from a vein. On the eve of the study, the patient should adhere to a hypocholesterol diet and lengthen night fasting to 14-16 hours, however, the doctor will inform him about this.

The indicator of total cholesterol is determined in the blood serum after centrifugation, triglycerides too, but you will have to work on the sedimentation of fractions, this is a more time-consuming study, but in any case, the patient will know about its results by the end of the day. What to do next - the numbers and the doctor will tell you.

Video: what the tests say. Cholesterol

There is a widespread misconception that cholesterol is harmful to the body, and its level in the blood is one of the most important indicators of a person's health. Many in an attempt to maintain their health adhere to strict diets, excluding all foods containing cholesterol. However, few people know that it is part of cell membranes, gives them strength and ensures the exchange of substances between the cell and the intercellular substance and regulates the activity of enzymes. Thus, without cholesterol, the normal functioning of our body is impossible.

Despite the importance of cholesterol, excessive consumption of fatty foods of animal origin can lead to an increased content in the body, which negatively affects health and can cause serious illness.

Controlling cholesterol levels will help maintain your health for many years, increase the body's natural resistance, increase life expectancy and improve its quality. In this article, we will dispel the most common myths about the role of cholesterol in our body and its metabolism. We will also look at the most effective ways to control cholesterol levels.

Cholesterol (from the Greek. chole - bile and stereo - solid, hard) - was first identified in gallstones from here and got its name. It is a natural water-insoluble lipophilic alcohol. About 80% of cholesterol is synthesized in the body (liver, intestines, kidneys, adrenal glands, gonads), the remaining 20% ​​must come from the food we consume.

Circulating in the bloodstream, cholesterol, if necessary, is used as a building material, as well as for the synthesis of more complex compounds. Since it is insoluble in water (and, accordingly, in the blood), its transportation is possible only in the form of complex water-soluble compounds, which are divided into 2 types:

Low density lipoproteins (LDL)

High density lipoproteins (HDL)

Both of these substances must be in a strictly defined ratio, their total volume must also not exceed the norm. This can lead to serious diseases of the cardiovascular system.

Functions of cholesterol in the body:

- ensuring the strength of cell walls, regulation of their permeability for various molecules;

- synthesis of vitamin D;

- synthesis of steroid (cortisone, hydrocortisone), male (androgens) and female (estrogens, progesterone) sex hormones by the adrenal glands;

- in the form of bile acids, it participates in the formation of bile and the absorption of fats during digestion;

- participates in the formation of new synapses in the brain, thereby improving mental abilities and memory.

In fact, it is not cholesterol as such that causes harm, but its fluctuations beyond the norm. Health problems can cause both excess and lack of it in the body.

The negative impact of cholesterol

According to statistics, people who died from cardiovascular diseases had low levels of high density lipoproteins, but high levels of low density lipoproteins.

Lipoproteins with their wrong ratio or prolonged high content in the blood can settle on the walls of blood vessels and cause atherosclerosis.

This dangerous disease occurs when plaques form on the vascular endothelium, which, over time, grow more and more and accumulate calcium. As a result, the lumen of the vessels narrows, they lose their elasticity (stenosis), which leads to a decrease in the supply of oxygen and nutrients to the heart and tissues and the development of angina pectoris (cessation of arterial blood flow to certain parts of the heart due to blockage of the coronary artery, accompanied by pain and discomfort in the chest) . Often, it is because of a violation of the blood supply that a heart attack or myocardial infarction occurs. The formation of cholesterol plaques leads to damage on the inner wall of the vessels, a blood clot can form, which can subsequently clog the artery or come off and cause an embolism. Also, a vessel that has lost its elasticity can burst with an increase in pressure in the bloodstream.

The role of lipoproteins

HDL is considered a "good" lipoprotein due to its ability to dissolve cholesterol plaques and remove it from the walls of arteries, the higher its percentage in relation to LDL ("bad" lipoprotein), the better. LDL transports cholesterol from the organs that synthesize it into the arteries, and with an increased content of this compound, these large insoluble molecules combine to form fatty plaques, attach to the vessels and clog them. Being subjected to oxidative processes, cholesterol loses its stability and can easily penetrate into the thickness of the walls of the arteries.

Specific antibodies begin to be produced in large quantities against the formed oxidized LDL, which leads to severe damage to the walls of the arteries. In addition, cholesterol lowers nitric oxide levels, increasing the risk of cardiovascular disease.

Nitric oxide plays an important role in the body:

- dilates blood vessels, lowers blood pressure, prevents the formation of blood clots in the bloodstream;

- plays an important role in the fight against bacteria and viruses that enter the body, destroys cancer cells;

- increases the endurance of muscle tissue;

- participates in the exchange of information between different cells, is a neurotransmitter in synapses.

HDL not only removes cholesterol from the blood back to the liver, but also prevents the oxidation of LDL.

Signs of high cholesterol levels in the body

An increase in cholesterol levels is associated with a violation of lipid (fat) metabolism. This can be a symptom not only of atherosclerosis, but also of other serious diseases:

- liver;

- kidneys (chronic renal failure, glomerulonephritis);

- pancreas (chronic pancreatitis);

- diabetes mellitus (a serious disease associated with a violation of the synthesis of beta cells of the islets of Langerhans in the pancreas);

- hypothyroidism (decreased synthesis of thyroid hormones);

- obesity.

Symptoms of atherosclerosis are caused by narrowing of the lumen of blood vessels as a result of prolonged and persistent elevated cholesterol levels, and deterioration of blood circulation in different parts of the bloodstream.

Main symptoms:

- angina pectoris (sudden discomfort or pain in the chest that occurs during exercise or emotional stress);

- shortness of breath;

- arrhythmia (violation of the heart rhythm);

- cyanosis and swelling of the peripheral parts of the body (fingers, toes);

- periodic cramps in the legs (intermittent claudication);

- memory impairment, inattention;

- decrease in intellectual abilities;

- yellow-pink lipid deposits in the skin (xanthomas), most often observed on the skin of the eyelids and in the ankle joints.

The impact of HDL and LDL levels on our health

Still, the opinion that the total level of HDL and LDL lipoproteins affects the state of health and their increase entails terrible consequences for the functioning of the whole organism. However, this statement is not entirely true. Yes, the above diseases will be accompanied by an increased content of lipoproteins in general, but what is much more important is the exact ratio of “good” HDL and “bad” LDL in the blood. It is the violation of this proportion that leads to health problems. When determining the content of lipoproteins in the blood, 4 indicators are taken into account: the total amount of cholesterol, the level of HDL, LDL and triglycerides.

Norms

Total cholesterol in the blood - 3.0 - 5.0 mmol/l;

With the threat of atherosclerosis, total cholesterol rises to 7.8 mmol / l;

LDL at men- 2.25 - 4.82 mmol / l;

LDL in women- 1.92 - 4.51 mmol / l;

HDL at men- 0.72 - 1.73 mmol / l;

HDL at women- 0.86 - 2.28 mmol / l;

Triglyceridesin men- 0.52 - 3.7 mmol / l;

Triglyceridesamong women- 0.41 - 2.96 mmol / l.

The most indicative is the ratio of HDL and LDL against the background of total cholesterol. In a healthy body, HDL is much higher than LDL.

The most effective treatments for high cholesterol

There are many drugs that lower cholesterol in cases where this indicator poses a serious threat to health, or already at the onset of atherosclerosis. It is necessary to pay tribute, an important part of which is proper nutrition. In such cases, diet and moderate exercise will help not only bring all blood counts back to normal, but also completely heal and rejuvenate your body.

For a faster therapeutic effect, pharmacological preparations are used:

— Statins- the most popular drugs, the principle of their action is to inhibit the synthesis of cholesterol in the liver by blocking the corresponding enzymes. Usually they are taken once a day at bedtime (at this time, the active production of cholesterol in the body begins). The therapeutic effect occurs after 1-2 weeks of systematic use, with prolonged use they are not addictive. Side effects may include nausea, abdominal and muscle pain, and in rare cases, there may be individual sensitivity. Drugs of the statin group can reduce cholesterol levels by 60%, but with their long-term use, it is necessary to regularly take tests for AST and ALT every six months. The most common statins are cerivastatin, fluvastatin, and lovastatin.

— Fibrates stimulate the production of HDL, are recommended when the amount of triglycerides is 4.5 mmol / l. Not recommended for use with statins. Side effects are manifested in the form of gastrointestinal disorders, flatulence, nausea, vomiting, and abdominal pain. Representatives of this group of drugs: clofibrate, fenofibrate, gemfibrozil.

— bile acid sequestrants. This group of drugs is not absorbed into the blood, but acts locally - it binds to bile acids, which are synthesized from cholesterol, and remove them from the body naturally. The liver begins to increase the production of bile acids, using more cholesterol from the blood, a visible positive effect occurs a month after the start of medication, to enhance the effect, simultaneous administration of statins is possible. Prolonged use of drugs can lead to impaired absorption of fats and vitamins, increased bleeding is possible. Side effects: flatulence, constipation. These drugs include: colestipol, cholestyramine.

— Cholesterol absorption inhibitors interfere with the absorption of lipids from the intestine. Drugs in this group can be prescribed to people who have contraindications to taking statins, since they are not absorbed into the blood. In Russia, only 1 drug of the group of cholesterol absorption inhibitors, ezetrol, is registered.

The above measures are used in advanced cases, when it is necessary to quickly reduce cholesterol levels, and lifestyle changes cannot quickly give the desired effect. But even when taking pharmacological agents, do not forget about prevention, and harmless natural supplements that, with long-term regular use, will help you prevent diseases of the cardiovascular system in the future.

Folk remedies to help lower blood cholesterol levels

- Niacin (nicotinic acid, vitamin PP, vitamin B 3). The mechanism of action is not fully understood, but experiments show that after a few days of taking high doses of the vitamin, the level of LDL and triglycerides in the blood decreases markedly, but the amount of HDL increases up to 30%. Unfortunately, it does not reduce the risk of developing cardiovascular complications and seizures. For maximum effectiveness, niacin can be combined with other treatments.

— . Contained in fish oil and seafood, as well as in vegetable oils of cold pressing (unrefined). They have a positive effect on the nervous system, prevent rickets during the period of active growth, help lower cholesterol and blood pressure, improve blood circulation, strengthen blood vessels and give them elasticity, prevent their thrombosis, participate in the synthesis of hormone-like substances - prostaglandins. Regular intake of sources of essential fatty acids will miraculously affect the functioning of the whole organism, in particular, it will help prevent the development of atherosclerosis.

— Vitamin E. An extremely strong antioxidant that prevents the breakdown of LDL and the formation of fatty plaques. For the onset of a positive effect, it is necessary to constantly use the vitamin in appropriate doses.

— Green tea contains polyphenols - substances that affect lipid metabolism, they reduce the level of "bad" cholesterol and increase the content of "useful". In addition, tea contains antioxidants.

- Garlic. Fresh garlic is recommended to use to lower cholesterol levels, prevent the formation of clots in the vessels (thinns the blood). The active components that make up garlic are sulfur-containing compounds, in particular, alliin.

— Soy protein. By action, they are similar to estrogens - they reduce the likelihood of atherosclerosis. Genistein prevents LDL oxidation due to its antioxidant properties. In addition, soy stimulates the production of bile, thereby helping to remove cholesterol from the body.

— Vitamins B 6 (pyridoxine), B 9 (folic acid), B 12 (cyanocobalamin). A sufficient amount of these vitamins in the diet contributes to the proper functioning of the heart muscle, significantly reduces the risk of developing atherosclerosis and coronary heart disease.

What factors contribute to high cholesterol levels and the development of atherosclerosis?

Most often, atherosclerosis affects people who have neglected their health for a long time. The sooner you change your lifestyle, the less likely you are to develop serious diseases. Here are 4 main factors that contribute to high blood cholesterol levels:

— Passive lifestyle. With low mobility, lack of physical activity, the level of "bad" cholesterol rises, creating a threat of the development of cardiovascular diseases.

— Obesity. Violation of lipid metabolism is closely related to high cholesterol. Overweight people are prone to various diseases of the cardiovascular system.

— Smoking. It leads to narrowing of the arteries, an increase in blood viscosity, thrombosis, entails the risk of heart disease.

— Consumption of fatty animal products in large quantities leads to an increase in LDL.

— Heredity. The predisposition to high cholesterol levels is genetically transmitted. Therefore, people whose relatives suffer from this pathology should carefully monitor their health.

Healthy lifestyle as a way to fight cholesterol

As long as you adhere to proper nutrition and an active lifestyle, the risk of developing various diseases decreases. This is especially true for people at risk. By changing your lifestyle, you improve the work of the whole organism, even despite the tendency to any pathologies, internal defense mechanisms can easily cope with the threat.

Active sports improve metabolism, train the heart muscle simultaneously with the skeletal muscles, contribute to a better blood supply to all organs and systems (during physical exertion, the blood from the depot goes into the general channel, this contributes to a better saturation of the organs with oxygen and nutrients).

Sports exercises also lead to the strengthening of the walls of blood vessels, prevent the development of varicose veins.

Don't forget the importance of proper nutrition. Do not abuse strict diets. The body must receive all the nutrients it needs in the optimal ratio, vitamins and minerals, fiber. The diet should contain enough vegetables, fruits, cereals, lean meat, sea and ocean fish, vegetable unrefined oils, milk and dairy products. If there is a lack of any vitamins in the diet, it is worth periodically taking preparations with their content to prevent beriberi.

Quitting smoking will reduce the risk of developing not only atherosclerosis, but also a number of other diseases, such as bronchitis, stomach ulcers, and cancer.

Sport is the best remedy for stress and depression, it tempers the nervous system. Regular physical activity, whether it's a run in the park or 3 hours of exercise in the gym, helps to remove the negativity and irritation accumulated over the whole day, many athletes experience euphoria during training. It has been experimentally proven that active people are much less prone to stress than those who lead a sedentary lifestyle.

Conclusion

As you can see, cholesterol is an extremely important compound that performs a number of vital functions. It is necessary for our life, but in the body its amount should not go beyond the norm. An imbalance in the ratio of high and low density lipoproteins entails serious consequences.

The best treatment is timely prevention. The most effective way to prevent high cholesterol levels in the blood is a healthy lifestyle.

When you give up bad habits and start adhering to the above rules, you will completely forget about health problems.

Cholesterol. Myths and deceit.

For a long time now, the whole world has been actively fighting cholesterol, or rather, its high content in the human body and the consequences of this. Scientists from different countries put forward their opinions and evidence on this matter, argue about their correctness and give arguments. To understand the benefits and harms of this substance for human life, it is necessary to find out the biological role of cholesterol. You will learn about the features, properties, as well as tips for controlling its content in the blood from this article.

The structure of cholesterol, its biological role

Translated from ancient Greek, cholesterol literally means "hard bile". It is an organic compound that is involved in the formation of cells of all living organisms, except for plants, fungi and prokaryotes (cells that do not have a nucleus).

The biological role of cholesterol is difficult to overestimate. In the human body, it performs a number of significant functions, the violation of which leads to pathological changes in health.

Functions of cholesterol:

• Participates in the structure of cell membranes, giving them elasticity and elasticity.
• Provides tissues.
• Takes part in the synthesis of hormones such as estrogens and corticoids.
• Affects the production of vitamin D and bile acids.

The peculiarity of cholesterol is that it is insoluble in water in its pure form. Therefore, for its transportation through the circulatory system, special "transport" compounds are used - lipoproteins.

Synthesis and receiving from the outside

Along with triglycerides and phospholipids, cholesterol is one of the three main types of fat in the body. It is a natural lipophilic alcohol. About 50% of cholesterol is synthesized daily in the human liver, 30% of its formation occurs in the intestines and kidneys, the remaining 20% ​​comes from outside - with food. The production of this substance occurs as a result of a long complex process in which six stages can be distinguished:

• production of mevalonate. This reaction is based on the breakdown of glucose to two molecules, after which they react with the substance acetoacetyltransferase. The result of the first stage is the formation of mevolanate.
• The preparation of isopentenyl diphosphate is carried out by adding three phosphate residues to the result of the previous reaction. This is followed by decarboxylation and dehydration.
• When three molecules of isopentenyl diphosphate are combined, farnesyl diphosphate is formed.
• After combining two residues of farnesyl diphosphate, squalene is synthesized.
• As a result of a complex process involving linear squalene, lanosterol is formed.
• At the final stage, the synthesis of cholesterol occurs.

Biochemistry confirms the important biological role of cholesterol. This process is clearly regulated by the human body in order to prevent an overabundance or deficiency of this important substance. The liver enzyme system is able to speed up or slow down the lipid metabolism reactions that underlie the synthesis of fatty acids, phospholipids, cholesterol, etc. Speaking about the biological role, function and metabolism of cholesterol, it is worth noting that about twenty percent of its total amount enters the body with food. It is found in large quantities in animal products. The leaders are egg yolk, smoked sausages, butter and ghee, goose liver, liver pate, kidneys. By limiting the intake of these foods, you can reduce the amount of cholesterol received from outside.

The chemical structure of this organic compound, as a result of metabolism, cannot be split into CO 2 and water. In this regard, most of the cholesterol is excreted from the body in the form of bile acids, the rest - with feces and unchanged.

"Good" and "bad" cholesterol

This substance is found in most tissues and cells of the human body, due to the biological role of cholesterol. It acts as a modifier of the cell bilayer, giving it rigidity, thereby stabilizing the fluidity of the plasma membrane. After synthesis in the liver, cholesterol must be delivered to the cells of the whole body. Its transportation occurs as part of highly soluble complex compounds called lipoproteins.

They are of three types:

• (high molecular weight).
• Low density lipoproteins (low molecular weight).
• Very low density lipoproteins (very low molecular weight).
• Chylomicrons.

These compounds are distinguished by their tendency to precipitate cholesterol. A relationship was established between the content of lipoproteins in the blood and human health. People who had high levels of LDL had atherosclerotic changes in the vessels. Conversely, for those who had HDL in their blood, a healthy body was characteristic. The thing is that low molecular weight transporters are prone to precipitation of cholesterol, which settles on the walls of blood vessels. That's why it's called "bad". On the other hand, high-molecular compounds, having a high solubility, are not atherogenic, therefore they are called "good".

Given the important biological role of cholesterol, its blood level should be within acceptable limits:

• in women, this rate varies from 1.92 to 4.51 mmol / l.
• in men - from 2.25 to 4.82 mmol / l.

At the same time, the level of LDL cholesterol should be less than 3-3.35 mmol / l, HDL - more than 1 mmol / l, triglycerides - 1 mmol / l. It is considered a good indicator if the amount of high-density lipoprotein is 20% of the total cholesterol. Deviations, both up and down, indicate health problems and require additional examination.

Causes of high blood cholesterol levels

• genetic changes of a hereditary nature;
• violation of the functions and activity of the liver - the main producer of lipophilic alcohol;
• hormonal changes;
• frequent stress;
• malnutrition (eating fatty foods of animal origin);
• metabolic disorders (pathology of the digestive system);
• smoking;
• sedentary lifestyle.

The danger of excess cholesterol in the body

Hypercholesterolemia contributes to the development of atherosclerosis (the formation of sclerotic plaques on the walls of blood vessels), coronary heart disease, diabetes, and the formation of gallstones. Thus, the important biological role and danger of changes in the level of cholesterol in the blood are reflected in pathological changes in human health.

Control

To avoid the unpleasant consequences of an increase in the level of "bad" cholesterol, it is necessary to prevent the growth of LDL and VLDL.

Anyone can do it, all you need to do is:

• reduce your intake of trans fats;
• increase the amount of fruits and vegetables in the diet;
• increase physical activity;
• avoid smoking;

If these rules are observed, the risk of high cholesterol in the blood is reduced several times.

Ways of decline

Conclusions about the level of cholesterol in the blood and the need to reduce it are made by medical specialists based on the results of the tests. Self-medication in this case can be dangerous.

With stably elevated cholesterol, mainly conservative methods are used to reduce it:

• The use of medications (statins).
• Maintaining a healthy lifestyle (proper nutrition, diet, physical activity, smoking cessation, quality and regular rest).

It is worth noting in conclusion: the structure and biological role of cholesterol, hypercholesterolemia and its consequences confirm the importance of this substance and all the processes associated with it for a person. Therefore, it is necessary to responsibly treat factors that can affect the quality and quantity of cholesterol in the body.