(hereinafter referred to as “X.”) is an organic compound from the class of steroids Steroids- a class of organic compounds widespread in nature. These include vitamins D, sex hormones, and adrenal hormones (corticosteroids). They are part of the molecules of steroid glycosides, including cardiac glycosides. Many steroids are obtained by chemical and microbiological synthesis.; the most important sterol in animals and humans. First isolated from gallstones (hence the name: Greek chole - bile). Colorless crystals with a melting point of 149 °C, insoluble in water, highly soluble in non-polar organic solvents.
A characteristic chemical property of cholesterol is the ability to form molecular complexes with many salts, acids, amines, proteins and neutral compounds such as saponins, vitamin D 3 (cholecalciferol), etc. Cholesterol is present in almost all living organisms Organism(from the medieval Latin organizo - arrange, impart a slender appearance) - Living being, which has a set of properties that distinguish it from inanimate matter. Most organisms have a cellular structure. The formation of a complete organism is a process consisting of differentiation of structures (cells, tissues, organs) and functions and their integration both in ontogenesis and phylogenesis., including bacteria Bacteria- a group of microscopic, mainly single-celled organisms. Globular (cocci), rod-shaped (bacillus, clostridia, pseudomonads), convoluted (vibrones, spirilla, spirochetes). Capable of growing both in the presence of atmospheric oxygen (aerobes) and in its absence (anaerobes). Many bacteria are causative agents of diseases in animals and humans. There are bacteria necessary for the normal process of life (Escherichia coli is involved in the processing of nutrients in the intestines, but when it is detected, for example, in urine, the same bacterium is considered to be the causative agent of kidney and urinary tract infections). and blue-green algae.
The chromium content in plants is usually low (with the exception of seed oils). In vertebrates, large amounts of chromium are contained in lipids Lipids(from the Greek “fat”), a large group of natural organic compounds, including fats and fat-like substances. Contained in all living cells. They form an energy reserve for the body, participate in the transmission of nerve impulses, in the creation of water-repellent and thermal insulating covers, etc. nervous tissue (where it is associated with the structural components of the myelin sheath), eggs and cells, in (the main organ of chromium biosynthesis), in the adrenal glands Adrenal glands- paired endocrine glands. The adrenal cortex secretes corticosteroid hormones, as well as partially male and female sex hormones, while the medulla secretes adrenaline and norepinephrine. The adrenal glands play an important role in regulating metabolism and in adapting the body to unfavorable conditions. Damage to the adrenal glands leads to diseases (Addison's disease, Itsenko-Cushing's disease, etc.)., in sebum and in cell walls. In plasma, cholesterol is found in the form of esters with higher fatty acids (oleic and others) and serves as a carrier during their transport: the formation of these esters occurs in the walls with the participation of the enzyme Enzymes(from the Latin "leaven") - biological catalysts present in all living cells. They carry out the transformation of substances in the body, thereby directing and regulating metabolism. By chemical nature- proteins.
Each type of enzyme catalyzes the transformation of certain substances (substrates), sometimes only a single substance in a single direction. Therefore, numerous biochemical reactions in cells are carried out by a huge number of different enzymes. Enzyme preparations are widely used in medicine. cholesterol esterase. Most organisms (with the exception of some annelids, mollusks, echinoderms, and sharks) are capable of synthesizing chromium from squalene.
The most important biochemical function of chromium in vertebrates is its transformation into a hormone in the placenta, corpus luteum, and adrenal glands; this transformation opens the chain of biosynthesis of steroid sex hormones and corticosteroids Corticosteroids- hormones produced by the adrenal cortex. They regulate mineral metabolism (the so-called mineralocorticoids - aldosterone, cortexone) and the metabolism of carbohydrates, proteins and fats (the so-called glucocorticoids - hydrocortisone, cortisone, corticosterone, which also affect mineral metabolism). They are used in medicine when they are deficient in the body (for example, Addison's disease), as anti-inflammatory and antiallergic agents.. Another direction of cholesterol metabolism in vertebrates is the formation of bile acids and D3. In addition, chromium is involved in the regulation of cell permeability and protects red blood cells from the action of hemolytic poisons. In insects, chromium supplied with food is used for the biosynthesis of ecdysones.
In a number of animals, a constant level of cholesterol in the body is regulated according to the principle feedback: when excess chromium is consumed with food, its biosynthesis in the cells of the body is inhibited (suppressed). In humans, this control mechanism is absent, so the content of chromium in the blood (normally 150 - 200 mg%) can increase noticeably, especially at the age of 30 - 60 years with fatty. This contributes to blockage of the bile ducts, fatty infiltration of the liver, the formation of gallstones, and the deposition of atherosclerotic plaques in cells containing chromium.
Cholesterol is excreted from the body of animals mainly through excrement (in the form of coprosterol). In the pharmaceutical industry, chromium serves as a raw material for the production of many steroid drugs. The main source of chromium is the spinal cord Spinal cord- central department nervous system, located in the spinal canal, is involved in most reflexes. In humans, it consists of 31-33 segments, each of which has 2 pairs of nerve roots: the anterior ones - the so-called motor ones, through which impulses from the cells of the spinal cord are transmitted to the periphery (to the skeletal muscles, vascular muscles, internal organs) and the posterior ones - the so-called sensitive, through which impulses from receptors of the skin, muscles, internal organs transmitted to the spinal cord. The anterior and posterior roots, connecting with each other, form mixed spinal nerves. The most complex reflex reactions of the spinal cord are controlled by the brain. lethal cattle. (E. P. Serebryakov)
For more information on cholesterol, see the literature:
- Biosynthesis of lipids. Symposium VII, M., 1962 (Proceedings of the V International Biochemical Congress, vol. 7);
- Myasnikov A.L., and, M., 1965;
- Heftman E.M., Biochemistry of steroids, trans. from English, M., 1972;
- Schwartzman A., Cholesterol and the heart, N. Y., 1965.
Find something else interesting:
Cholesterol is a steroid vital for the body. It is an essential component of lipid metabolism and is involved in the synthesis of hormones. The substance is part of all cells, its amount in the brain is about 60%. For various reasons, the concentration of cholesterol may exceed the norm. This has a negative impact on health.
So, what to do when cholesterol in the blood is elevated, and what does it mean.
What is the difference between cholesterol and cholesterol?
The better known name for cholesterol is cholesterol. “Chole” is translated as “bile”, and “sterol” is translated as “fat”. In 1859 it was proven that the substance was an alcohol. That is why it was given the name “cholesterol”. The ending “-ol” indicates that it belongs to alcohols.
Thus, the answer to the question “is there a difference between cholesterol and cholesterol” will be negative. This is the same substance, which has 2 names. From point of view chemical classification It is more correct to call it “cholesterol”.
The compound is a liquid crystal. Over 80% of cholesterol is produced by the body on its own, the remaining 20% must come from outside along with food. It is very important that the diet contains sufficient quantity substances necessary for the synthesis of the steroid.
If the balance of cholesterol intake and output is disturbed, its concentration changes. This causes some diseases.
Cholesterol performs the following functions:
The process of cholesterol formation
Internal (endogenous) cholesterol is synthesized in all tissues. The main process takes place in the liver. The synthesis of endogenous cholesterol occurs as follows. The parent compound is acetyl coenzyme A (acetyl-CoA).
Biosynthesis consists of 3 stages: 
- Conversion of mevalonic acid into active isoprene, 6 molecules of which are converted to squalene;
- Conversion of squalene to cholesterol.
The molecular formula of cholesterol is C27H45OH. Approximately 1 g of steroid is produced per day. About 30 enzymes that act as catalysts take part in the reaction. They are found in the cytoplasm of cells.
A significant number of endogenous cholesterol molecules are converted into esters (the so-called esterified form). This happens by adding fatty acids. The compounds are located in the hydrophobic inner core of lipoproteins or form a form of steroid deposition in the liver, gonads, and adrenal cortex. Subsequently, the substance is used to form bile acids and hormones.
External (exogenous) cholesterol enters the body with food. A large amount of this substance is found in animal fats. Plant steroids are practically not absorbed, but are eliminated in feces.
IN food products cholesterol esters are present. The breakdown (hydrolysis) is carried out under the influence of an enzyme called cholesterol esterase. As a result, cholesterol and fatty acids are formed. The latter are absorbed by the cells of the small intestine and enter the blood. There they bind to albumin and are transported to the liver.
Cholesterol is also absorbed by the small intestine, where it is converted into esters when interacting with acetyl coenzyme A. Chylomicrons (lipoprotein complexes) are synthesized from them. They deliver fats to muscles and adipose tissue.
From 1.8 to 2.5 g of exogenous and endogenous cholesterol enters the intestines per day. The main part of it is absorbed in the small intestine. Approximately 0.5 g is excreted in the feces in the form of bile acids.
What are lipoproteins
Cholesterol is transported to tissues by proteins. Together they make up lipoproteins. This complex compounds, which are divided into 3 classes:
Total cholesterol
Total cholesterol includes: free cholesterol, esterified cholesterol (in the form of esters) and contained in lipoproteins. In cells, the steroid is present in the outer layer of membranes. In the blood, approximately 1/3 is in the form of free cholesterol and 2/3 in the form of compounds.
Cholesterol levels depend on the following factors: 
- Rate of absorption in the small intestine;
- Metabolic activity through lipoproteins;
- The rate of release of cholesterol in the form of bile acids.
The normal level of total cholesterol is 3.0-6.0 mmol/l. The LDL norm for men is 2.25-4.82 mmol/l, for women - 1.92-4.51 mmol/l; HDL for men - 0.7-1.73 mmol/l, for women - 0.86-2.28 mmol/l.
Estrogens help lower, and androgens increase, total cholesterol. In men, its amount increases in early and middle age, and in old age it decreases. In women, the concentration of the steroid increases more slowly with age.
During pregnancy, total cholesterol and LDL in the blood increase, due to physiological reasons.
Consequences of cholesterol imbalance
Cholesterol deficiency leads to the development of pathologies. These include:
Men experience sexual dysfunction, women experience amenorrhea. Cholesterol deficiency during pregnancy leads to severe developmental disorders of the fetus. The consequence of steroid deficiency in newborns and young children is rickets.
If total cholesterol is elevated, there is a high probability of developing various pathologies. The most dangerous is an increase in the amount of LDL. These substances are harmful to the heart and blood vessels. The cholesterol contained in such compounds forms plaques in the arteries. This causes the development of sclerosis.
Complications appear in the future: 
- Ischemia;
- Heart attack;
- Endarteritis;
- Stroke;
- Hypertension.
Such diseases cause disability and death.
Why does cholesterol increase?
If cholesterol in the blood is elevated, this means there are metabolic disorders that need to be paid attention to. This condition is called “hyperlipidemia.” Exceeding the norm indicators indicates large quantities low density lipoproteins.
There are several causes of lipid imbalance:
Low total blood cholesterol is usually found in those who eat foods that contain limited amounts of saturated fat and in people taking certain medications (such as estrogens).
Other reasons:
- Unbalanced, low-calorie diets;
- Starvation;
- Acute infections;
- Some diseases (pulmonary tuberculosis, heart failure).
Indications for a blood test for cholesterol
The determination of total cholesterol is used in the diagnosis of lipid metabolism disorders and to assess the risk of sclerosis and its complications. The resulting value makes it possible to determine the activity of the steroid formation process in the liver.
Indications for a blood test for cholesterol:
Blood is taken from a vein in the morning on an empty stomach. The last meal should be 12-14 hours before the procedure.
How to lower cholesterol
What to do if cholesterol in the blood is elevated? To do this, it is necessary to eliminate all risk factors.
If the cholesterol value is 6.6-7.7 mmol/l, adjust the menu: 
- Limit your intake of sources of “bad” cholesterol (pork, fatty dairy products, eggs, foods containing margarine);
- Use vegetable oil instead of butter;
- Eat as little sweets and starchy foods as possible;
- Include more vegetables and fruits in your diet.
Adjust your lifestyle by eliminating bad habits. Excess weight needs to be reset. Enlarge motor activity. This has a positive effect on reducing cholesterol concentrations, since it stimulates blood circulation, improves blood oxygen saturation, and helps remove excess steroid. Spend at least 1 hour a day on sports training.
Adequate sleep is important for the health of the body. It should last at least 8 hours a day. Try to avoid stressful situations.
If the reading is 8.8-9.9 (LDL over 4.4) mmol/l, you should consult a doctor. You may have to undergo a cardiovascular, digestive, endocrine systems. The doctor will help you find the cause of the pathology and prescribe a course of treatment.
For the purpose of drug therapy of hyperlipidemia, the following groups of drugs are used: 
- Fibrates;
- Cholesterol absorption inhibitors;
- Bile acid sequestrants;
- Nicotinic acid and its derivatives.
Medicines reduce the absorption of cholesterol and lower its concentration. They improve metabolism, which helps eliminate excess steroids.
The listed drugs are also prescribed if changes in lifestyle and diet do not affect cholesterol concentrations. The most effective are statins, which inhibit the process of steroid synthesis.
How to increase cholesterol
To increase “good” cholesterol, enter into the menu:
- Cold sea fish (salmon, trout, mackerel, tuna, cod, etc.);
- Vegetables, legumes containing a lot of fiber;
If the cause of low cholesterol is a diet, it is recommended to abandon it or take a break. Fats cannot be completely eliminated: they are a building material and a source of energy for the body's cells.
Healthy and unhealthy fats
The amount of calories that the body receives from fat should not be more than 30% of daily norm(600-800 kcal for people who do not engage in physical labor). You need to consume only natural fats. Your cholesterol level will depend on their quality.
There are 4 types of fats: monounsaturated, polyunsaturated, saturated, and trans fats. Monounsaturated ones reduce LDL concentrations, increasing HDL.
They are found in the following products:
Food must contain Omega-3 polyunsaturated fatty acids, which the body is not able to synthesize on its own. With a deficiency of these substances, the formation of cholesterol plaques intensifies.
Sources of Omega-3: 
- Seafood;
- Soybean oil, linseed oil;
- Walnuts.
Excess polyunsaturated fats contained in sunflower and pumpkin seeds do not lead to the formation of sclerotic plaques. However, you should not eat such food in too large quantities.
Saturated fats are found in the following foods:
Abuse of such foods increases cholesterol levels. The content of these substances in the menu should not exceed 1/3 of total number fats entering the body.
Trans fats are very harmful. They increase the concentration of “bad” cholesterol, reducing “good” cholesterol. Trans fats come from vegetable oils. This method produces margarine, which is a component of semi-finished products, confectionery, and baked goods.
So, adjusting your lifestyle and daily menu (diet composition, type and amount of fat) helps maintain normal cholesterol levels. It is necessary to undergo regular medical examinations and donate blood for cholesterol. This will allow timely detection of the development of hyperlipidemia and other pathologies.
The role of cholesterol in the human body is very important. The level of cholesterol in the blood can be used to judge a person's health status - up to recently Many people believed in this myth, doctors talked about it. This explains the belief that chicken eggs, in particular their yolk, are extremely dangerous, like lard, and in general any fats of animal origin, and therefore they should be discarded.
However, cholesterol in the blood is at least, when he is normal, has done nothing to deserve such a reputation.
Many people are interested in the meaning of cholesterol, its beneficial features, action, structure, what affects the increase in cholesterol in the blood, diseases that it can provoke.
But if a person controls his cholesterol level, he will never feel bad, on the contrary. This substance is not at all harmful or dangerous; after reading this article, you will be convinced of this. But it is important to ensure that its quantity does not exceed the established standards. Below is how to do this correctly, and in general, take care of your well-being.
Free cholesterol belongs to the group of lipids - special fat cells that are needed for the structure of cell membranes. This is well known to those who are involved in painbuilding, because athletes who want to increase muscle mass, be sure to include in your diet not only proteins, but also lipids. In this case, if you abuse fatty foods, serious health problems can actually arise. First, lipid metabolism is disrupted, then the blood vessels begin to suffer, and eventually severe pathologies of the heart and brain develop.
What is cholesterol?
This substance is from the group of lipids, the name comes from the ancient Greek: “chole” (bile) and “stereo” (solid, hard). Why? Because for the first time it was isolated from a gallstone in a transformed, solid form. Beneficial cholesterol is synthesized by liver cells - from there up to 80% of it enters the bloodstream. Everything else is what entered the body with food. Fatty elements circulate throughout the bloodstream, but it can also be found, in addition to the liver, in the brain and muscles. It helps to better absorb vitamins, is involved in the structure of new cells and the production of testosterone, estrogen and cortisol. And thanks to this substance, antioxidants get into the tissues. Cholesterol in men becomes elevated with age much more often than cholesterol in women.
But cholesterol is not found in pure form, but in the form of compounds. If LDL and HDL are in balance and total cholesterol is within normal limits, everything is fine. But if the balance is disturbed, health problems begin. This happens more often when bad cholesterol is elevated.
It is not cholesterol itself that you need to be afraid of - without it, the production of bile, a substance necessary for the breakdown and absorption of fats, would not be possible - this is the benefit of cholesterol. You need to be afraid of changes in the ratio between LDL (the so-called bad cholesterol) and HDL (good), as well as if total cholesterol increases. This can really lead to the most serious pathologies of the heart and blood vessels.
Harmful effects of cholesterol
In 1999, there were approximately 530,000 deaths in the United States due to cardiovascular diseases, of which in half of the cases - as doctors do not exclude - high cholesterol was to blame. It was an increase in LDL and a decrease in HDL that led to heart pathologies leading to death.
Both of these fat-like substances constantly circulate in the blood and complement each other’s functions. That's what cholesterol is. But if the balance between them is disturbed, harmful cholesterol is deposited on the walls of the arteries, they harden - diseases such as atherosclerosis develop. At the beginning body fat loose, but if LDL is deposited more and more, they become fibrous and calcium salts accumulate in them. In this case, the heart can suffer doubly:
- The vascular lumen narrows due to the accumulation of calcium salts on the walls of the arteries (scientific calcification) and loses its elasticity (stenosis). Less blood flows to the heart, which means less oxygen. If a narrowing of the coronary arteries occurs, angina pectoris develops - heart pain, shortness of breath, and general discomfort. If the blockage is complete, myocardial infarction may occur due to insufficient blood supply. So what is cholesterol for?
- Sometimes the plaques break off - then a dense clot is formed, which circulates along with the blood and can also clog any of the arteries. Depending on which vessels are affected, the patient has a heart attack or stroke.
Chemical formula of cholesterol in blood
Cholesterol (for convenience, hereinafter referred to as X) is an organic compound that belongs to the group of sterols. For humans, it is one of the most important steroids; it was first isolated in solid form from gallstones. X is a colorless crystal with a melting point of 149 degrees Celsius and is insoluble in water but soluble in non-polar organic solvents. Moreover, it was believed that cholesterol in the human body is a harmful substance that must be gotten rid of.
The chemical formula of cholesterol is:
One of the main chemical properties of this substance - to create complexes with molecules of various salts, acids, amines, proteins, saponins, vitamins D3 and some other neutral compounds. Cholesterol can be found in the body of almost all animals, in blue-green algae and microorganisms. Cholesterol in men triggers its action more often and causes various diseases.
Plants, as a rule, contain very small amounts of X, with the exception of pollen and seeds. Why do we need cholesterol in the blood? There is incomparably more cholesterol in vertebrates; it can be found in the fat cells of this nervous tissue, eggs and seminal fluid, in the liver, adrenal glands, in sebum and red blood cell membranes.
Every body needs it - the biological role of cholesterol - for the normal implementation of numerous metabolic processes, for example, the synthesis of sex hormones. And, in addition, most of it is produced by our own liver, and only a small amount comes with food, including egg yolks. The cholesterol that is found in the blood serum is an ester with higher fatty acids and performs transport functions. Almost all animals and organisms of other classes, except sharks, mollusks, annelids and bacteria, synthesize cholesterol independently from a substance called squalene. Its essential biochemical function is the conversion to the hormone progesterone in the adrenal glands, placenta, testes and corpus luteum, which stimulates the biosynthesis of corticosteroids and steroid sex hormones.
CS is also involved in the production of bile acid and vitamin D - but also only in vertebrates. This is how cholesterol is exchanged in the body. It regulates the permeability of cell membranes and protects red blood cells from hemolytic poisons. The amount of the hormone in animals is regulated according to the feedback principle: if it is supplied in excess along with food, then the liver begins to produce it in smaller quantities. But man is built differently. Normally, the X content in the blood of adults should not exceed 150-200 mg, but if the diet is dominated by fatty foods, then these indicators increase.
The accumulation of X causes blockage of the biliary tract, fatty liver tissue, the formation of gallstones and the formation of cholesterol plaques on the walls of the arteries. Cholesterol composition: ratio of low-density lipoproteins and high-density lipoproteins. In animals, X is excreted mainly with excrement.
Cholesterol is widely used by pharmacists to make steroid preparations, the raw material for this is extract from the spinal cord of cattle. (according to E.P. Serebryakov).
The meaning and functions of cholesterol in the body
The main significance of cholesterol in the blood is that without it it is impossible to build almost all cells; thanks to it, their membranes remain permeable, but at the same time remain strong and elastic. These are also its beneficial properties. Also, without the participation of cholesterol, the production of sex hormones, bile, and partly vitamin D is impossible, and various diseases develop.
If the body finds itself in a stressful situation, the level of cholesterol increases and becomes beneficial for the body. This is necessary in order to restore damaged tissues and cells. That is, cholesterol also performs protective function. The benefits of cholesterol are extensive. if its level is normal, a person will not get a disease such as atherosclerosis. If its level is reduced for a long time, then red blood cells begin to be destroyed very quickly, but they are replenished with new ones much more slowly. With a deficiency of cholesterol, the risk of developing a disease such as anemia increases. It always remains necessary.
The results indicate these indicators, as well as total cholesterol. These are the diverse and irreplaceable functions and actions that cholesterol performs in the human body; any disturbances in its content in the blood, whether greater or lesser, lead to serious disruptions in the functioning of almost all internal organs.
Cholesterol is one of the important substances in the body. It is part of all cell membranes in tissues and organs. This substance is a precursor to corticosteroid and sex hormones, bile acids, vitamin D and others.
However, cholesterol can also cause harm to the body. They talk about “bad” and “good” cholesterol. Violation of its balance in the composition of different classes of lipoproteins leads to the development of atherosclerosis.
What are cholesterol and lipoproteins
Cholesterol is synthesized mainly in the liver and also enters the body with food. With proper nutrition, about 500 mg of cholesterol per day enters the human body with food, and approximately the same amount is formed in the body itself (50% in the liver, 15% in the intestines, the rest in the skin).
Cholesterol molecules from food are absorbed in the intestines and enter the blood. It is transported to tissues as part of special protein-lipid complexes - lipoproteins. They contain proteins - apoproteins, cholesterol, as well as other lipid substances - triglycerides. The more cholesterol there is in such a complex, the lower its density. Based on this criterion, low-density lipoproteins (LDL), very low-density lipoproteins (VLDL) and high-density lipoproteins (HDL) are distinguished.
VLDL is synthesized in the liver. LDL is formed from them. The latter are the richest in cholesterol. They can contain up to 2/3 of the total cholesterol in the blood plasma. LDL play main role in the transport of cholesterol into the vascular wall and in the formation.
It is known that the higher the body’s need for building material for the formation of new cell membranes, the greater the need for steroid hormones, the lower the LDL content in the blood and the less likely the formation of atherosclerotic plaques in the vessels.
HDL is synthesized in the liver. They contain less cholesterol compared to LDL. These lipoproteins carry out reverse transport of cholesterol from blood vessels, organs and tissues, converting it into other lipoproteins or transporting it directly to the liver with subsequent removal from the body with bile. The higher the level of HDL in the blood and the greater the proportion of cholesterol contained in them, the lower the likelihood of developing atherosclerosis and the greater the possibility of reverse development of atherosclerotic plaques.
In the human body, about 70% of cholesterol is contained in LDL, 10% in VLDL and 20% in HDL.
"Bad" and "good" cholesterol
An increase in the level of low-density lipoproteins in the blood leads to the formation of atherosclerotic plaques in the vessels.Cholesterol, which is part of LDL, has an atherogenic effect. In common parlance, this complex is called “bad” cholesterol. In contrast, HDL cholesterol is called “good” cholesterol.
An increase in LDL levels and cholesterol content in them, on the one hand, and a decrease HDL concentrations and their cholesterol content, on the other hand, create conditions for the formation of atherosclerotic plaques and the progression of related diseases, in particular.
On the contrary, a decrease in the level of LDL in the blood and an increase in the concentration of HDL create conditions not only for stopping the development of atherosclerosis, but also for its regression.
They used to say: “Without cholesterol there is no atherosclerosis.” Considering very important role, which lipoproteins play in this process, they say: “Without lipoproteins there is no atherosclerosis.”
Cholesterol levels are normal and in various diseases
Blood serum taken on an empty stomach contains cholesterol and three types of lipoproteins - VLDL, LDL and HDL, in which it is contained and by which it is transported. Total cholesterol is the sum of these three components.
The normal cholesterol level is no more than 5.2 mmol/l. Moderate hypercholesterolemia (increased cholesterol concentration in the blood) – up to 6.5 mmol/l. Levels up to 7.8 mmol/l are considered severe hypercholesterolemia, in which mortality from coronary disease heart rate increases 5 or more times. Very high hypercholesterolemia – more than 7.8 mmol/l.
Normal LDL cholesterol levels are 2.3–5.4 mmol/L.
Plasma cholesterol concentrations are usually elevated in diabetes mellitus, suppressed thyroid function (hypothyroidism), and obesity. Elevated cholesterol levels are an independent risk factor for the development of atherosclerosis and its manifestations - coronary heart disease, obliterating atherosclerosis, and cerebrovascular accidents.
Reduced blood cholesterol levels are often observed with infectious diseases, intestinal diseases with impaired absorption of nutrients, increased thyroid function (hyperthyroidism), exhaustion.
Atherogenic coefficient
The ratio of “bad” and “good” cholesterol can be assessed using the so-called atherogenic coefficient (CAT).
CAT = (Cs – HDL Cs)/HDL Cs, where
Xc – total cholesterol content in blood plasma;
At the age of 20–30 years, this figure is 2–2.8. In people over 30 years of age without signs of atherosclerosis, the CAT value is 3–3.5. In coronary heart disease, the CAT value exceeds 4, which indicates the predominance of “bad” LDL cholesterol in the total fraction.
Diet plays an important role in the treatment of hypercholesterolemia. In this case, it is necessary to take into account the cholesterol content of foods in order to limit its consumption.
A diet aimed at treating atherosclerosis should include no more than 300 mg of cholesterol per day. Based on this table, you can determine how much and what foods you can eat to combat this serious disease.
Which doctor should I contact?
We get excess cholesterol and harmful lipoproteins by eating unhealthy, fatty foods. To find out what your cholesterol level is, contact your local physician and get the appropriate tests. If cholesterol concentrations are high, you need to change your diet, which a nutritionist will help you with. If atherosclerosis caused by hypercholesterolemia has already manifested itself clinically, then specialized specialists - a cardiologist (for coronary heart disease), a neurologist (for cerebral atherosclerosis), and a vascular surgeon (for intermittent claudication) - will help cope with its consequences.
10. Structure and functions of cholesterol.
This is a special waxy substance that has its own structure, properties and structural formula. It is classified as a steroid because it contains cyclic structures. Structural formula cholesterol is written as follows: C27H46O. Under normal conditions, in purified form, it is a substance consisting of small crystals. Their melting point is about 149 °C. With a further increase in temperature they boil (about 300°C).
Cholesterol is present only in animal organisms; it is not found in plants. In the human body, cholesterol is found in the liver, spinal cord, brain, adrenal glands, gonads, and adipose tissue; is part of the membranes of almost all cells. Breast milk contains a lot of cholesterol. The total amount of this substance in our body is approximately 350 g, of which 90% is found in tissues and 10% in the blood (in the form of esters with fatty acids). More than 8% of the brain's dense matter consists of cholesterol.
Most of the cholesterol is produced by the body itself (endogenous cholesterol), much less comes from food (exogenous cholesterol). Approximately 80% of this substance is synthesized in the liver, the rest of the cholesterol is produced in the wall of the small intestine and some other organs.
Without cholesterol, the normal functioning of vital organs and systems of our body is impossible. It is part of cell membranes, ensuring their strength and regulating their permeability, as well as influencing the activity of membrane enzymes.
The next function of cholesterol is its participation in metabolic processes, the production of bile acids necessary for the emulsification and absorption of fats in the small intestine, and various steroid hormones, including sex hormones. With the direct participation of cholesterol, the body produces vitamin D (which plays a role in key role in the metabolism of calcium and phosphorus), adrenal hormones (cortisol, cortisone, aldosterone), female sex hormones (estrogens and progesterone), male sex hormone testosterone.
Therefore, cholesterol-free diets are also harmful because long-term adherence to them often leads to sexual dysfunction (in both men and women).
In addition, cholesterol is essential for normal brain function. According to the latest scientific data, cholesterol directly affects a person’s intellectual abilities, as it takes part in the formation of new synapses by neurons in the brain, which ensure the reactive properties of nervous tissue.
And even LDL, “bad” cholesterol, is also necessary for our body, since it plays a leading role in the functioning of the immune system, including protection against cancer. It is low-density lipoproteins that can neutralize various bacteria and toxins that enter the blood. Therefore, a lack of fat in the diet is just as harmful as an excess of it. Nutrition should be regular, balanced and meet the individual needs of the body, depending on living conditions, physical activity, individual characteristics, gender and age.
11. Lipoproteins (lipoproteins)- a class of complex proteins. Thus, lipoproteins may contain free fatty acids, neutral fats, phospholipids, and cholesterol. Lipoproteins are complexes consisting of proteins (apolipoproteins; abbreviated as apo-LP) and lipids, the connection between which is carried out through hydrophobic and electrostatic interactions. Lipoproteins are divided into free, or water-soluble (lipoproteins of blood plasma, milk, etc.), and insoluble, so-called. structural (lipoproteins of cell membranes, myelin sheath of nerve fibers, plant chloroplasts). Among free lipoproteins (they occupy a key position in the transport and metabolism of lipids), the most studied are blood plasma lipoproteins, which are classified according to their density. The higher their lipid content, the lower the lipoprotein density. There are very low density lipoproteins (VLDL), low density lipoproteins (LDL), high density lipoproteins (HDL) and chylomicrons. Each group of lipoproteins is very heterogeneous in particle size (the largest are chylomicrons) and the content of apo-lipoproteins in it. All groups of plasma lipoproteins contain polar and nonpolar lipids in different proportions.
|
Dimensions |
Function |
|
|
High density lipoproteins (HDL) |
Transport of cholesterol from peripheral tissues to the liver |
|
|
Low-density lipoproteins (LDL) | ||
|
Intermediate-density lipoproteins (DILI) |
Transport of cholesterol, triacylglycerides and phospholipids from the liver to peripheral tissues |
|
|
Very low density lipoproteins (VLDL) |
Transport of cholesterol, triacylglycerides and phospholipids from the liver to peripheral tissues |
|
|
Chylomicrons |
Transport of dietary cholesterol and fatty acids from the intestine to peripheral tissues and the liver |
12.Bile acids- monocarboxylic hydroxy acids from the class of steroids, derivatives of cholanic acid C23H39COOH. The main types of bile acids circulating in the human body are the so-called primary bile acids, which are primarily produced by the liver, cholic and chenodeoxycholic, as well as secondary ones, formed from primary bile acids in the colon under the influence of intestinal microflora: deoxycholic, lithocholic, allocholic and ursodeoxycholic . Of the secondary acids, only deoxycholic acid, which is absorbed into the blood and then secreted by the liver as part of bile, participates in noticeable quantities in the enterohepatic circulation. Structure of chendesoxycholic acid. In the bile of the human gallbladder, bile acids are found in the form of conjugates of cholic, deoxycholic and chenodeoxycholic acids with glycine and taurine: glycocholic, glycodeoxycholic, glycochenodeoxycholic, taurocholic, taurodeoxycholic and taurochenodeoxycholic acid - compounds also called paired acids. ursofalk (ursodeoxycholic acid). Different mammals have different sets of bile acids. Bile acids, chenodeoxycholic and ursodeoxycholic, are the basis of drugs used in the treatment of gallbladder diseases. Recently, ursodeoxycholic acid has been recognized as an effective treatment for bile reflux.
Metabolism of bile acids. In a healthy person with a gallbladder, primary bile acids synthesized in hepatocytes are excreted into bile conjugated with glycine or taurine and enter the gallbladder through the biliary tract, where they accumulate. A small amount of bile acids (approximately 1.3%) is absorbed in the walls of the gallbladder. Normally, the main pool of bile acids is in gallbladder and only after stimulation with food does the gallbladder contract reflexively and bile acids enter the duodenum. Secondary bile acids (deoxycholic and lithocholic) are formed from primary bile acids (cholic and chenodeoxycholic, respectively) under the influence of anaerobic bacteria of the colon. After reabsorption of secondary bile acids, they are conjugated with glycine or taurine, from which they also become components of bile. Ursodeoxycholic acid, a tertiary bile acid, is also formed under the action of microbial enzymes. From the intestine, bile acids with the portal blood flow again enter the liver, which absorbs almost all bile acids from the portal blood (approximately 99%); a very small amount (about 1%) enters the peripheral blood.