Interesting facts about lipids in the human body. Fats: Important facts that are interesting to know. Study preparation

Lipids - These are fat-like organic compounds that are insoluble in water, but readily soluble in non-polar solvents (ether, gasoline, benzene, chloroform, etc.). Lipids belong to the simplest biological molecules.

Chemically, most lipids are esters of higher carboxylic acids and a number of alcohols. The most famous among them are fats. Each fat molecule is formed by a molecule of the trihydric alcohol glycerol and ester bonds of three molecules of higher carboxylic acids attached to it. According to the accepted nomenclature, fats are called triacylglycerols.

Carbon atoms in the molecules of higher carboxylic acids can be connected to each other by both single and double bonds. Of the limiting (saturated) higher carboxylic acids, most often in the composition of fats are palmitic, stearic, arachidic; from unsaturated (unsaturated) - oleic and linoleic.

The degree of unsaturation and the chain length of higher carboxylic acids (i.e., the number of carbon atoms) determine the physical properties of a particular fat.

Fats with short and unsaturated acid chains have a low melting point. At room temperature, these are liquids (oils) or greasy substances (fats). Conversely, fats with long and saturated chains of higher carboxylic acids become solid at room temperature. That's why hydrogenation (saturation of acid chains with hydrogen atoms in double bonds) liquid peanut butter, for example, becomes greasy, and sunflower oil turns into solid margarine. Compared with the inhabitants of the southern latitudes, the body of animals living in a cold climate (for example, fish in the Arctic seas) usually contains more unsaturated triacylglycerols. For this reason, their body remains flexible even at low temperatures.

In phospholipids, one of the extreme chains of the higher carboxylic acids of triacylglycerol is replaced by a group containing phosphate. Phospholipids have polar heads and non-polar tails. The groups forming the polar head are hydrophilic, while the non-polar tail groups are hydrophobic. The dual nature of these lipids determines their key role in the organization of biological membranes.

Another group of lipids are steroids (sterols). These substances are built on the basis of cholesterol alcohol. Sterols are poorly soluble in water and do not contain higher carboxylic acids. These include bile acids, cholesterol, sex hormones, vitamin D, etc.

Terpenes also belong to lipids (growth substances of plants - gibberellins; carotenoids - photosynthetic pigments; essential oils of plants, as well as waxes).

Lipids can form complexes with other biological molecules - proteins and sugars.

The functions of lipids are as follows:

Structural. Phospholipids together with proteins form biological membranes. The membranes also contain sterols.
Energy. When fats are oxidized, a large amount of energy is released, which goes to the formation of ATP. In the form of lipids, a significant part of the body's energy reserves are stored, which are consumed when there is a lack of nutrients. Hibernating animals and plants accumulate fats and oils and use them to maintain life processes. The high content of lipids in plant seeds ensures the development of the embryo and seedling before their transition to independent nutrition. Seeds of many plants (coconut palm, castor bean, sunflower, soybean, rapeseed, etc.) serve as raw materials for industrial production of vegetable oil.
Protective and heat-insulating. Accumulating in the subcutaneous tissue and around certain organs (kidneys, intestines), the fat layer protects the animal body and its individual organs from mechanical damage. In addition, due to its low thermal conductivity, the layer of subcutaneous fat helps to retain heat, which allows, for example, many animals to live in cold climates. In whales, in addition, it plays another role - it contributes to buoyancy.
Lubricating and water repellent. Wax coats the skin, wool, feathers, makes them more elastic and protects them from moisture. Leaves and fruits of many plants have a wax coating.
Regulatory. Many hormones are derivatives of cholesterol, such as sex hormones (testosterone in men and progesterone in women) and corticosteroids (aldosterone). Derivatives of cholesterol, vitamin D play a key role in the exchange of calcium and phosphorus. Bile acids are involved in the processes of digestion (emulsification of fats) and absorption of higher carboxylic acids.

Lipids are also a source of metabolic water formation. Oxidation of 100 g of fat gives approximately 105 g of water. This water is very important for some desert dwellers, in particular for camels, which can go without water for 10-12 days: the fat stored in the hump is used for this purpose. Bears, marmots and other hibernating animals receive the water necessary for life as a result of fat oxidation.

In the myelin sheaths of axons of nerve cells, lipids are insulators during the conduction of nerve impulses.

Wax is used by bees in building honeycombs.

Determination of blood lipid profile indicators is necessary for the diagnosis, treatment and prevention of cardiovascular diseases. The most important mechanism for the development of such a pathology is the formation of atherosclerotic plaques on the inner wall of the vessels. Plaques are accumulations of fat-containing compounds (cholesterol and triglycerides) and fibrin. The higher the concentration of lipids in the blood, the more likely the appearance of atherosclerosis. Therefore, it is necessary to systematically take a blood test for lipids (lipidogram), this will help to identify deviations of fat metabolism from the norm in a timely manner.

Lipidogram - a study that determines the level of lipids of various fractions

Atherosclerosis is dangerous with a high probability of developing complications - stroke, myocardial infarction, gangrene of the lower extremities. These diseases often end in disability of the patient, and in some cases, death.

Role of lipids

Lipid functions:

Structural. Glycolipids, phospholipids, cholesterol are the most important components of cell membranes.
Thermal insulation and protective. Excess fats are deposited in the subcutaneous fat, reducing heat loss and protecting internal organs. If necessary, the lipid reserve is used by the body for energy and simple compounds.
Regulatory. Cholesterol is necessary for the synthesis of steroid hormones of the adrenal glands, sex hormones, vitamin D, bile acids, is part of the myelin sheaths of the brain, and is needed for the normal functioning of serotonin receptors.

Lipidogram

A lipidogram can be prescribed by a doctor both if an existing pathology is suspected, or for preventive purposes, for example, during a medical examination. It includes several indicators that allow you to fully assess the state of fat metabolism in the body.

Lipidogram indicators:

Total cholesterol (OH). This is the most important indicator of the lipid spectrum of the blood, it includes free cholesterol, as well as cholesterol contained in lipoproteins and associated with fatty acids. A significant part of cholesterol is synthesized by the liver, intestines, gonads, only 1/5 of the OH comes from food. With normally functioning mechanisms of lipid metabolism, a small deficiency or excess of cholesterol from food is compensated by an increase or decrease in its synthesis in the body. Therefore, hypercholesterolemia is most often caused not by excessive intake of cholesterol from foods, but by a failure of the fat metabolism process.
High density lipoproteins (HDL). This indicator has an inverse relationship with the likelihood of developing atherosclerosis - an elevated HDL level is considered an anti-atherogenic factor. HDL transport cholesterol to the liver, where it is utilized. Women have higher HDL levels than men.
Low density lipoproteins (LDL). LDL carries cholesterol from the liver to the tissues, otherwise known as "bad" cholesterol. This is due to the fact that LDL can form atherosclerotic plaques that narrow the lumen of blood vessels.

This is what an LDL particle looks like

Very low density lipoproteins (VLDL). The main function of this group of particles, heterogeneous in size and composition, is the transport of triglycerides from the liver to tissues. A high concentration of VLDL in the blood leads to clouding of the serum (chylosis), and the possibility of atherosclerotic plaques also increases, especially in patients with diabetes mellitus and kidney pathologies.
Triglycerides (TG). Like cholesterol, triglycerides are transported through the bloodstream as part of lipoproteins. Therefore, an increase in the concentration of TG in the blood is always accompanied by an increase in cholesterol levels. Triglycerides are considered the main source of energy for cells.
Atherogenic coefficient. It allows you to assess the risk of developing vascular pathology and is a kind of outcome of the lipid profile. To determine the indicator, you need to know the value of OH and HDL.

Atherogenic coefficient \u003d (OH - HDL) / HDL

Optimal blood lipid profile values

Floor	Index, mmol/l
Floor	OH	HDL	LDL	VLDL	TG	KA
Male	3,21 — 6,32	0,78 — 1,63	1,71 — 4,27	0,26 — 1,4	0,5 — 2,81	2,2 — 3,5
Female	3,16 — 5,75	0,85 — 2,15	1,48 — 4,25	0,26 — 1,4	0,41 — 1,63	2,2 — 3,5

It should be borne in mind that the value of the measured indicators may vary depending on the units of measurement, the methodology for conducting the analysis. Normal values also vary depending on the age of the patient, the above figures are averaged for persons 20-30 years old. The norm of cholesterol and LDL in men after 30 years tends to increase. In women, the indicators increase sharply with the onset of menopause, this is due to the cessation of the anti-atherogenic activity of the ovaries. Deciphering the lipidogram must be carried out by a specialist, taking into account the individual characteristics of a person.

The study of blood lipid levels may be prescribed by a doctor to diagnose dyslipidemia, assess the likelihood of developing atherosclerosis, in some chronic diseases (diabetes mellitus, kidney and liver diseases, thyroid gland), and also as a screening study for early detection of individuals with abnormal lipid profiles from the norm .

The doctor gives the patient a referral for a lipidogram

Study preparation

Lipidogram values can fluctuate not only depending on the gender and age of the subject, but also on the impact on the body of various external and internal factors. To minimize the likelihood of an unreliable result, you must adhere to several rules:

Donate blood should be strictly in the morning on an empty stomach, in the evening of the previous day, a light dietary dinner is recommended.
Do not smoke or drink alcohol on the eve of the study.
2-3 days before donating blood, avoid stressful situations and intense physical exertion.
Refuse to use all medications and dietary supplements, except for vital ones.

Methodology

There are several methods for laboratory assessment of the lipid profile. In medical laboratories, analysis can be carried out manually or using automatic analyzers. The advantage of an automated measurement system is the minimum risk of erroneous results, the speed of obtaining an analysis, and the high accuracy of the study.

The analysis requires the patient's venous blood serum. Blood is taken into a vacuum tube using a syringe or vacutainer. To avoid the formation of a clot, the blood tube should be inverted several times, then centrifuged to obtain serum. The sample can be stored in the refrigerator for 5 days.

Taking blood for lipid profile

Currently, blood lipids can be measured without leaving home. To do this, you need to purchase a portable biochemical analyzer that allows you to assess the level of total cholesterol in the blood or several indicators at once in a matter of minutes. For research, you need a drop of capillary blood, it is applied to the test strip. The test strip is impregnated with a special composition, for each indicator it has its own. The results are read automatically after inserting the strip into the device. Due to the small size of the analyzer, the ability to operate on batteries, it is convenient to use it at home and take it with you on a trip. Therefore, persons with a predisposition to cardiovascular diseases are advised to have it at home.

Interpretation of results

The most ideal result of the analysis for the patient will be a laboratory conclusion that there are no deviations from the norm. In this case, a person can not be afraid for the state of his circulatory system - the risk of atherosclerosis is practically absent.

Unfortunately, this is not always the case. Sometimes the doctor, after reviewing the laboratory data, makes a conclusion about the presence of hypercholesterolemia. What it is? Hypercholesterolemia - an increase in the concentration of total cholesterol in the blood above normal values, while there is a high risk of developing atherosclerosis and related diseases. This condition may be due to a number of reasons:

Heredity. Science knows cases of familial hypercholesterolemia (FH), in such a situation, a defective gene responsible for lipid metabolism is inherited. In patients, a constantly elevated level of TC and LDL is observed, the disease is especially severe in the homozygous form of FH. In such patients, early onset of coronary artery disease (at the age of 5-10 years) is noted, in the absence of proper treatment, the prognosis is unfavorable and in most cases ends in death before reaching 30 years of age.
Chronic diseases. Elevated cholesterol levels are observed in diabetes mellitus, hypothyroidism, kidney and liver pathology, due to lipid metabolism disorders due to these diseases.

For patients with diabetes, it is important to constantly monitor cholesterol levels.

Wrong nutrition. Prolonged abuse of fast food, fatty, salty foods leads to obesity, while, as a rule, there is a deviation in lipid levels from the norm.
Bad habits. Alcoholism and smoking lead to malfunctions in the mechanism of fat metabolism, as a result of which the lipid profile increases.

With hypercholesterolemia, it is necessary to follow a diet with a restriction of fat and salt, but in no case should you completely refuse all foods rich in cholesterol. Only mayonnaise, fast food and all foods containing trans fats should be excluded from the diet. But eggs, cheese, meat, sour cream must be present on the table, you just need to choose products with a lower percentage of fat. Also in the diet it is important to have greens, vegetables, cereals, nuts, seafood. The vitamins and minerals contained in them perfectly help to stabilize lipid metabolism.

An important condition for the normalization of cholesterol is also the rejection of bad habits. Good for the body and constant physical activity.

In the event that a healthy lifestyle in combination with a diet has not led to a decrease in cholesterol, it is necessary to prescribe an appropriate drug treatment.

Drug treatment of hypercholesterolemia includes the appointment of statins

Sometimes specialists are faced with a decrease in cholesterol levels - hypocholesterolemia. Most often, this condition is due to insufficient intake of cholesterol from food. Fat deficiency is especially dangerous for children, in such a situation there will be a lag in physical and mental development, cholesterol is vital for a growing body. In adults, hypocholesteremia leads to a violation of the emotional state due to malfunctions of the nervous system, problems with reproductive function, decreased immunity, etc.

A change in the blood lipid profile inevitably affects the work of the whole organism as a whole, therefore it is important to systematically monitor the indicators of fat metabolism for timely treatment and prevention.

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The site provides reference information for informational purposes only. Diagnosis and treatment of diseases should be carried out under the supervision of a specialist. All drugs have contraindications. Expert advice is required!

lipids in nutrition

Along with proteins and carbohydrates, lipids are the main food elements that make up a significant part of food. The intake of lipids in the body with food has a significant impact on human health in general. Insufficient or excessive consumption of these substances can lead to the development of various pathologies.

Most people eat a fairly varied diet, and all the necessary lipids enter their body. It should be noted that some of these substances are synthesized by the liver, which partly compensates for their lack in food. However, there are also essential lipids, or rather their components - polyunsaturated fatty acids. If they do not enter the body with food, over time this will inevitably lead to certain disorders.

Most of the lipids in food are used by the body to produce energy. That is why when fasting a person loses weight and weakens. Deprived of energy, the body begins to consume lipid reserves from subcutaneous adipose tissue.

Thus, lipids play a very important role in a healthy human diet. However, for certain diseases or disorders, their number should be strictly limited. Patients usually learn about this from the attending physician ( usually a gastroenterologist or nutritionist).

The energy value of lipids and their role in the diet

The energy value of any food is calculated in calories. A food product can be decomposed according to its composition into proteins, carbohydrates and lipids, which together make up the bulk. Each of these substances in the body breaks down with the release of a certain amount of energy. Proteins and carbohydrates are easier to digest, but the breakdown of 1 g of these substances releases about 4 Kcal ( kilocalories) energy. Fats are more difficult to digest, but the breakdown of 1 g releases about 9 kcal. Thus, the energy value of lipids is the highest.

In terms of energy release, triglycerides play the largest role. Saturated acids, which are part of these substances, are absorbed by the body by 30 - 40%. Monounsaturated and polyunsaturated fatty acids are completely absorbed by a healthy body. Sufficient lipid intake allows carbohydrates and proteins to be used for other purposes.

Plant and animal lipids

All lipids that enter the body with food can be divided into substances of animal and vegetable origin. From a chemical point of view, the lipids that make up these two groups differ in their composition and structure. This is due to differences in the functioning of cells in plants and animals.

Examples of plant and animal lipid sources

Each source of lipids has certain advantages and disadvantages. For example, animal fats contain cholesterol, which is not found in plant foods. In addition, animal products contain more lipids and are more beneficial from an energy point of view. At the same time, an excess of animal fats increases the risk of developing a number of diseases associated with lipid metabolism in the body ( atherosclerosis, cholelithiasis, etc.). There are fewer lipids in plant products, but the body cannot synthesize them on its own. Even a small amount of seafood, citrus fruits or nuts provides enough polyunsaturated fatty acids that are vital for a person. At the same time, a small proportion of lipids in plants cannot fully cover the energy costs of the body. That is why, to maintain health, it is recommended to make the diet as varied as possible.

What is the daily requirement of the body for lipids?

Lipids are the body's main source of energy, but too much of them can be detrimental to health. First of all, this applies to saturated fatty acids, most of which are deposited in the body and often leads to obesity. The optimal solution is to maintain the necessary proportions between proteins, fats and carbohydrates. The body should receive the same number of calories that it spends during the day. That is why lipid intake rates can be different.

The following factors can influence the body's need for lipids:

Body weight. Overweight people have to expend more energy. If they are not going to lose weight, then the need for calories and, accordingly, lipids will be slightly higher. If they are trying to lose weight, then limit, in the first place, you need exactly fatty foods.
Loads during the day. People doing heavy physical work or athletes need a lot of energy. If the average person has 1500 - 2500 calories, then for miners or loaders the norm can reach up to 4500 - 5000 calories per day. Of course, the need for lipids also increases.
The nature of nutrition. Every country and every nation has its own food traditions. When calculating the optimal diet, one must take into account which foods a person usually consumes. In some peoples, fatty foods are a kind of tradition, while others, on the contrary, are vegetarians, and their lipid intake is minimized.
The presence of comorbidities. In a number of disorders, lipid intake should be limited. First of all, we are talking about diseases of the liver and gallbladder, since these organs are responsible for the digestion and absorption of lipids.
The age of the person. In childhood, the metabolism is faster and the body requires more energy for normal growth and development. In addition, children usually do not have serious problems with the gastrointestinal tract, and they digest any food well. It should also be borne in mind that infants receive an optimal set of lipids from breast milk. Thus, age strongly influences the rate of fat intake.
Floor. It is believed that on average a man consumes more energy than a woman, so the rate of fat in the diet of men is somewhat higher. However, in pregnant women, the need for lipids increases.

It is estimated that a healthy adult male working 7 to 8 hours a day and maintaining an active lifestyle should consume about 2,500 calories per day. Fats provide approximately 25 - 30% of this energy, which corresponds to 70 - 80 g of lipids. Of these, saturated fatty acids should be about 20%, and polyunsaturated and monounsaturated fatty acids should be about 40% each. It is also recommended to give preference to lipids of plant origin ( about 60% of the total).

It is difficult for a person to independently make the necessary calculations and take into account all the factors for choosing the optimal diet. To do this, it is better to consult a dietitian or food hygienist. After a short survey and clarification of the nature of nutrition, they will be able to draw up the optimal daily diet, which the patient will adhere to in the future. They can also recommend specific foods that contain essential lipids.

What foods contain the most lipids? milk, meat, etc.)?

Lipids are found in some amount in almost all foods. However, in general, animal products are richer in these substances. In plants, the mass fraction of lipids is minimal, but the fatty acids included in such lipids are most important for the body.

The amount of lipids in a particular product is usually indicated on the packaging of the product in the "nutrition value" section. Most manufacturers are required to inform consumers about the mass fraction of proteins, carbohydrates and fats. In self-cooked food, the amount of lipids can be calculated using special tables for nutritionists, which list all the main foods and dishes.

Mass fraction of lipids in staple foods

In most plant products ( vegetables, fruits, herbs, root crops) mass fraction of fats is not more than 1 - 2%. The exceptions are citrus fruits, where the proportion of lipids is somewhat higher, and vegetable oils, which are a lipid concentrate.

Are there essential lipids, and what are their most important sources?

The structural unit of lipids are fatty acids. Most of these acids can be synthesized by the body ( mostly in liver cells) from other substances. However, there are a number of fatty acids that the body cannot produce on its own. Thus, lipids containing these acids are essential.

Most of the essential lipids are found in foods of plant origin. These are monounsaturated and polyunsaturated fatty acids. The cells of the body cannot synthesize these compounds, since the metabolism of animals is very different from that of plants.

Essential fatty acids and their main dietary sources

For a long time, the above fatty acids were equal in importance to the body to vitamins. Sufficient consumption of these substances strengthens the immune system, accelerates cell regeneration, reduces inflammation, and promotes the conduction of nerve impulses.

What does a lack or excess of lipids in the diet lead to?

Both deficiency and excess of lipids in the diet can seriously affect the health of the body. In this case, we are not talking about a one-time intake of a large amount of fat ( although this may have some consequences.), but about the systematic abuse of fatty foods or prolonged fasting. At first, the body is quite capable of successfully adapting to a new diet. For example, with a lack of lipids in food, the most important substances for the body will still be synthesized by its own cells, and energy needs will be covered by the breakdown of fat reserves. With an excess of lipids in the diet, a significant part will not be absorbed in the intestines and will leave the body with fecal matter, and some of the lipids that enter the bloodstream are transformed into adipose tissue. However, these adaptation mechanisms are temporary. In addition, they work well only in a healthy body.

Possible Consequences of Dietary Lipid Imbalance

Blood and plasma lipids

A significant part of lipids is present in the blood in various forms. Most often, these are compounds of lipids with other chemicals. For example, triglycerides and cholesterol are transported primarily as lipoproteins. The levels of various lipids in the blood can be determined using biochemical blood tests. This allows you to identify a number of violations and suspect the corresponding pathology.

Triglycerides

Triglycerides perform mainly an energy function. They enter the body with food, are absorbed in the intestines and are carried throughout the body with the blood in the form of various compounds. The normal content is considered to be the level of 0.41 - 1.8 mmol / l, but it can fluctuate significantly. For example, after eating a large amount of fatty foods, the level of triglycerides in the blood can increase by 2 to 3 times.

Free fatty acids

Free fatty acids enter the bloodstream as a result of the breakdown of triglycerides. Normally, they are deposited in adipose tissue. Modern studies have shown the relationship between the level of free fatty acids in the blood and some pathological processes. For example, in people with a high concentration of fatty acids ( on an empty stomach) insulin is produced worse, so the risk of developing diabetes is higher. The normal content of fatty acids in the blood of an adult is 0.28 - 0.89 mmol / l. In children, the limits of the norm are wider ( up to 1.10 mmol/l).

Cholesterol

Cholesterol is one of the most important lipids in the human body. It is part of many cellular components and other substances, affecting a variety of processes. An excess or deficiency of this substance or a violation of its absorption by the body can lead to the development of serious diseases.

Cholesterol performs the following functions in the human body:

gives rigidity to cell membranes;
takes part in the synthesis of steroid hormones;
is part of bile;
participates in the absorption of vitamin D;
regulates the permeability of the walls of some cells.

Lipoproteins ( lipoproteins) and their fractions ( low density, high density, etc.)

The term lipoproteins or lipoproteins refers to a group of complex protein compounds that carry out the transport of lipids in the blood. Some lipoproteins are fixed in cell membranes and perform a number of functions related to cell metabolism.

All blood lipoproteins are divided into several classes, each of which has its own characteristics. The main criterion by which lipoproteins are distinguished is their density. According to this indicator, all these substances are divided into 5 groups.

There are following classes ( factions) lipoproteins:

high density. HDL) are involved in the transfer of lipids from body tissues to the liver. From a medical point of view, they are considered useful, because due to their small size they can pass through the walls of blood vessels and “cleanse” them of lipid deposits. Thus, a high level of HDL reduces the risk of atherosclerosis.
Low density. LDL) transport cholesterol and other lipids from the liver ( places of their synthesis) to tissues. From a medical point of view, this fraction of lipoproteins is harmful, since it is LDL that contributes to the deposition of lipids on the walls of blood vessels with the formation of atherosclerotic plaques. High LDL levels greatly increase the risk of atherosclerosis.
Medium ( intermediate) density. Intermediate density lipoproteins ( LPPP) have no significant diagnostic value, as they are an intermediate product of lipid metabolism in the liver. They also carry lipids from the liver to other tissues.
Very low density. VLDL) transport lipids from the liver to tissues. They also increase the risk of atherosclerosis, but play a minor role in this process ( after LDL).
Chylomicrons. Chylomicrons are much larger than other lipoproteins. They are formed in the walls of the small intestine and carry lipids from food to other organs and tissues. These substances do not play a significant role in the development of various pathological processes.

Currently, the biological role and diagnostic value of most lipoproteins has been disclosed, but there are still some questions. For example, the mechanisms that increase or decrease the level of one or another fraction of lipoproteins are not fully understood.

Lipid analysis

Currently, there are many laboratory tests that can determine various lipids in the blood. Usually venous blood is taken for this. The attending physician sends the patient for analysis. The most important lipids ( total cholesterol, triglycerides) is determined in a biochemical blood test. If the patient needs a more detailed examination, the doctor indicates which lipids need to be determined. The analysis itself usually takes several hours. Most labs provide results the next day.

What is a lipid profile?

Lipidogram is a set of laboratory blood tests aimed at determining the level of lipids in the blood. This is the most useful study for patients with various lipid disorders, as well as for patients with atherosclerosis. Some indicators included in the lipid profile are also determined in a biochemical blood test, but in some cases this may not be enough to make an accurate diagnosis. The lipid profile is prescribed by the attending physician, based on the symptoms and complaints of the patient. This analysis is carried out by almost any biochemical laboratory.

Lipidogram includes tests to determine the following blood lipids:

Cholesterol. This indicator does not always depend on lifestyle and nutrition. A significant part of cholesterol in the blood is the so-called endogenous cholesterol, which is produced by the body itself.
Triglycerides. Triglyceride levels usually rise or fall in proportion to cholesterol levels. It can also rise after eating.
Low density lipoproteins ( LDL). The accumulation of these compounds in the blood greatly increases the risk of atherosclerosis.
High density lipoproteins ( HDL). These compounds are able to "cleanse" the vessels from excess cholesterol and are beneficial to the body. A low HDL level indicates that the body is not absorbing fats well.
Very low density lipoproteins ( VLDL). They are of secondary diagnostic value, but their increase, along with an increase in LDL levels, usually indicates atherosclerosis.

If necessary, other indicators can be added to the lipidogram. Based on the results, the laboratory can issue, for example, an atherogenic index, which reflects the risk of developing atherosclerosis.

Before donating blood for a lipid profile, you should follow a few simple rules. They will help to avoid significant fluctuations in blood lipid levels and make the results more reliable.

Before testing, patients should consider the following recommendations:

In the evening before the test, you can eat, but you should not abuse fatty foods. It is better to stick to the usual diet.
The day before the test, it is necessary to exclude various kinds of loads ( both physical and emotional), as they can lead to the breakdown of adipose tissue stores in the body and an increase in blood lipid levels.
In the morning, immediately before donating blood, you should not smoke.
Regular intake of a number of drugs also affects the level of lipids in the blood ( contraceptives, hormonal drugs, etc.). It is not necessary to cancel them, but this fact must be taken into account when interpreting the results.

Based on the lipid profile, doctors can make the correct diagnosis and prescribe the necessary treatment.

Normal blood lipid levels

The boundaries of the norm for all people are somewhat different. It depends on gender, age, the presence of chronic pathologies and a number of other indicators. However, there are certain limits, the excess of which clearly indicates the presence of problems. The table below shows the generally accepted limits of the norm for various blood lipids.
The limits of the norm are relative, and the patient himself cannot always draw the right conclusions when interpreting the results of the analysis. When reviewing the results, the attending physician will definitely take into account that during pregnancy, the limits of the norm expand, as with fasting. Therefore, you should not panic with some deviations from the norm. In any case, the final conclusion should be made by the attending physician.

Diseases associated with lipid metabolism

There are quite a few diseases that are to some extent associated with the metabolism of lipids in the body. Some of these pathologies cause an increase or decrease in various lipids in the blood, which is reflected in the tests. Other pathologies are the result of lipid imbalance.

lipid metabolism disorders ( dyslipidemia)

Excess or lack of lipids in the diet can lead to a variety of pathologies. In a healthy body, normally assimilating all incoming substances, this imbalance does not affect metabolic processes so much. For example, an excess of lipids does not always lead to obesity. To do this, a person must also have a genetic predisposition, endocrine disorders, or he must lead a sedentary lifestyle. In other words, the amount of lipids in the diet in most cases is only one of many factors influencing the appearance of pathology.

Lipid imbalance can lead to the following pathologies:

atherosclerosis ( as a result - aneurysms, coronary heart disease, hypertension or other problems with the cardiovascular system);
skin problems;
problems with the nervous system;
a number of pathologies of the gastrointestinal tract ( pancreatitis, cholelithiasis, etc.).

Lack of dietary lipids in young children can affect weight gain and developmental speed.

Causes of high and low lipid levels

The most common cause of elevated lipid levels in a blood test is a mistake made when donating blood. Patients do not donate blood on an empty stomach, which is why the lipid content does not have time to normalize, and the doctor may mistakenly suspect some problems. However, there are many pathologies that cause lipid disorders in the blood, regardless of nutrition.

Pathological conditions associated with changes in the amount of lipids in the blood are called dyslipidemias. They are also divided into several types. If the level of triglycerides in the blood is elevated, they speak of hypertriglyceridemia ( synonym - hyperlipemia). If the level of cholesterol rises, they speak of hypercholesterolemia.

Also, all dyslipidemias by origin are divided into the following groups:

Primary. Primary dyslipidemias are mainly genetic diseases and abnormalities. As a rule, they are manifested by an excess or deficiency of any enzymes, which disrupts lipid metabolism. As a result, the amount of these substances in the blood decreases or increases.
Secondary. Secondary dyslipidemias are pathological conditions in which an increase in blood lipids is a consequence of some other pathology. Thus, it is necessary to treat, first of all, this particular pathology, then the lipid level will gradually stabilize.

The main task of the attending physician is the correct diagnosis, based on the results of the tests and the symptoms of the patient. Secondary dyslipidemias are more common and are usually the first to be ruled out. Primary dyslipidemias are much less common, but they are much more difficult to diagnose and treat.

There are five main types of primary hyperlipoproteinemias ( elevated lipoprotein levels):

Hyperchylomicronemia. With this disease, the level of triglycerides in the blood rises, while the level of other lipids usually remains within the normal range. Patients may experience paroxysmal abdominal pain, but without tension in the abdominal muscles. Xanthomas may appear on the skin ( brown or yellowish formations). The disease does not lead to the development of atherosclerosis.
Familial hyper-beta-lipoproteinemia. With this pathology, the number of beta-lipoproteins increases, and sometimes pre-beta lipoproteins. The analysis significantly exceeded the level of cholesterol. Triglycerides may be normal or slightly elevated. Patients also develop xanthomatosis ( xanthomas on the skin). Significantly increases the risk of atherosclerosis. With this disease, myocardial infarction is possible even at a young age.
Familial hypercholesterolemia with hyperlipemia. In the blood, the level of both cholesterol and triglycerides is significantly increased. Xanthomas are large and appear after 20-25 years. Increased risk of developing atherosclerosis.
Hyper-pre-beta-lipoproteinemia. In this case, the level of triglycerides rises, and the level of cholesterol remains within the normal range. The disease is often combined with diabetes, gout or obesity.

Occasionally, essential hyperlipemia also occurs ( Buerger-Grutz disease). The above diseases are diagnosed on the basis of electrophoresis data. You can suspect one of these pathologies as follows. In healthy people, after a meal with an abundance of fatty foods, lipemia is observed ( mainly due to the level of chylomicrons and beta-lipoproteins), which disappears after 5-6 hours. If the level of triglycerides in the blood does not subside, tests should be performed to identify primary hyperlipoproteinemias.

There are also secondary symptomatic) hyperlipoproteinemia in the following diseases:

Diabetes. In this case, the excess of lipids in the blood is explained by the transformation of excess carbohydrates.
Acute pancreatitis. With this disease, the absorption of lipids is impaired, and their level in the blood increases due to the breakdown of adipose tissue.
Hypothyroidism. The disease is caused by a lack of thyroid hormones, which regulate, among other things, lipid metabolism in the body.
Intrahepatic cholestasis and other pathologies of the liver. The liver is involved in the synthesis of most lipids needed by the body. With various hepatitis, disorders of the outflow of bile and other pathologies of the liver and bile ducts, the level of lipids in the blood may increase.
nephrotic syndrome. This syndrome develops when the glomerular apparatus of the kidneys is damaged. Patients present with severe renal edema. In the blood, the level of proteins decreases, and the level of cholesterol rises significantly.
Porfiry. Porphyria is a disease with a hereditary predisposition. In patients, the metabolism of a number of substances is disturbed, as a result of which porphyrins accumulate in the blood. In parallel, lipid levels may increase ( sometimes significantly).
Some autoimmune diseases. In autoimmune diseases, antibodies produced by the body attack their own cells. In most cases, chronic inflammatory processes develop, which are associated with an increase in lipid levels.
Gout. With gout, the metabolism of uric acid is disturbed in the body, and it accumulates in the form of salts. This is partly reflected in lipid metabolism, although their level in this case is slightly increased.
Alcohol abuse. Alcohol abuse leads to pathologies of the liver and gastrointestinal tract. A number of enzymes that increase blood lipid levels can be activated.
Taking certain medications. An increase in lipid levels can be caused, for example, by long-term use of oral contraceptives ( contraceptives). Most often, this side effect is mentioned in the instructions for the corresponding drug. Before taking the test, such drugs should not be taken, or the radiation doctor should be warned about this so that he correctly interprets the results of the analysis.

In the vast majority of cases, the cause of persistently elevated blood lipids is one of the above problems. It should also be noted that elevated lipid levels can be observed for quite a long time after serious injuries or myocardial infarction.

Also, an increased level of lipoproteins in the blood can be observed during pregnancy. This increase is usually small. With an increase in lipid levels 2 to 3 times higher than normal, the likelihood of pregnancy should be considered in combination with other pathologies that cause an increase in lipid levels.

What diseases of the digestive system are associated with lipid metabolism?

A healthy digestive system is essential for good absorption of lipids and other nutrients. A significant imbalance of lipids in food for a long time can lead to the development of some pathologies of the stomach. One of the most common problems in cardiology is atherosclerosis. This disease occurs due to the deposition of lipids in the vessels ( predominantly in arteries). As a result of this process, the lumen of the vessel narrows and blood flow becomes more difficult. Depending on which arteries are affected by atherosclerotic plaques, patients may experience different symptoms. The most characteristic are high blood pressure, coronary heart disease ( sometimes myocardial infarction), the appearance of aneurysms.

Atherogenic lipids are those substances that lead to the development of atherosclerosis. It should be noted that the division of lipids into atherogenic and non-atherogenic is very conditional. In addition to the chemical nature of substances, many other factors contribute to the development of this disease.

Atherogenic lipids more often lead to the development of atherosclerosis in the following cases:

heavy smoking;
heredity;
diabetes;
overweight ( obesity);
sedentary lifestyle ( hypodynamia) and etc.

In addition, it is not so much the substances consumed that are important in assessing the risk of atherosclerosis ( triglycerides, cholesterol, etc.), but rather the process of assimilation of these lipids by the body. In the blood, a significant part of lipids is present in the form of lipoproteins - compounds of lipid and protein. Low-density lipoproteins are characterized by "settlement" of fats on the walls of blood vessels with the formation of plaques. High-density lipoproteins are considered "anti-atherogenic", as they help cleanse blood vessels. Thus, with the same diet, some people develop atherosclerosis, while others do not. Both triglycerides and saturated and unsaturated fatty acids can transform into atherosclerotic plaques. But it depends on the metabolism in the body. In general, however, it is believed that a significant excess of any lipid in the diet predisposes to the development of atherosclerosis. Before use, you should consult with a specialist.

Lipids - what is it? Translated from Greek, the word "lipids" means "small particles of fat." They are a group of compounds of natural organics of an extensive nature, including directly fats, as well as fat-like substances. They are part of all living cells without exception and are divided into simple and complex categories. The composition of simple lipids includes alcohol and fatty acids, and complex ones contain high-molecular components. Both are associated with biological membranes, have an effect on active enzymes, and also participate in the formation of nerve impulses that stimulate muscle contractions.

Fats and hydrophobia

One of them is the creation of an energy reserve of the body and the provision of water-repellent properties of the skin, coupled with thermal insulation protection. Some fat-containing substances that do not have fatty acids are also classified as lipids, for example, terpenes. Lipids are not affected by the aquatic environment, but are easily soluble in organic liquids such as chloroform, benzene, acetone.

Lipids, which are periodically presented at international seminars in connection with new discoveries, are an inexhaustible topic for research and scientific research. The question "Lipids - what is it?" never loses its relevance. However, scientific progress does not stand still. Recently, several new fatty acids have been identified that are biosynthetically related to lipids. The classification of organic compounds can be difficult due to the similarity in certain characteristics, but with a significant difference in other parameters. Most often, a separate group is created, after which the overall picture of the harmonious interaction of related substances is restored.

Cell membranes

Lipids - what is it in terms of functional purpose? First of all, they are the most important component of living cells and tissues of vertebrates. Most of the processes in the body occur with the participation of lipids, the formation of cell membranes, the relationship and exchange of signals in the intercellular environment cannot do without fatty acids.

Lipids - what are they, if we consider them from the standpoint of spontaneously occurring steroid hormones, phosphoinositides and prostaglandins? This is, first of all, the presence in the blood plasma which, by definition, are separate components of lipid structures. Because of the latter, the body is forced to develop the most complex systems for their transportation. Fatty acids of lipids are mainly transported in complex with albumins, and water-soluble lipoproteins are transported in the usual way.

Lipid classification

The categorization of biological compounds is a process that involves some controversial issues. Lipids in connection with biochemical and structural properties can be attributed equally to different categories. The main classes of lipids include simple and complex compounds.

The simple ones are:

Glycerides are esters of glycerol alcohol and fatty acids of the highest category.
Waxes are an ester of a higher fatty acid and a 2-alcohol.

Complex lipids:

Phospholipid compounds - with the inclusion of nitrogenous components, glycerophospholipids, ofphingolipids.
Glycolipids - located in the outer biological layers of the body.
Steroids are highly active substances of the animal spectrum.
Complex fats - sterols, lipoproteins, sulfolipids, aminolipids, glycerol, hydrocarbons.

Functioning

Lipid fats act as material for cell membranes. Participate in the transport of various substances around the periphery of the body. Fat layers based on lipid structures help protect the body from hypothermia. They have the function of energy accumulation "in reserve".

Fat reserves are concentrated in the cytoplasm of cells in the form of droplets. Vertebrate animals, including humans, have special cells - adipocytes, which are able to contain quite a lot of fat. The placement of fat accumulations in adipocytes occurs due to lipoid enzymes.

biological functions

Fat is not only a reliable source of energy, it also has thermal insulating properties, which is facilitated by biology. Lipids at the same time allow you to achieve several useful functions, such as the natural cooling of the body or, conversely, its thermal insulation. In the northern regions, which are characterized by low temperatures, all animals accumulate fat, which is deposited evenly throughout the body, and thus a natural protective layer is created that performs the function of heat protection. This is especially important for large marine animals: whales, walruses, seals.

Animals living in hot countries also accumulate fat deposits, but they are not distributed throughout the body, but are concentrated in certain places. For example, in camels, fat is collected in humps, in desert animals - in thick, short tails. Nature carefully monitors the correct placement of both fat and water in living organisms.

Structural function of lipids

All processes associated with the vital activity of an organism are subject to certain laws. Phospholipids are the basis of the biological layer of cell membranes, and cholesterol regulates the fluidity of these membranes. Thus, most living cells are surrounded by plasma membranes with a double layer of lipids. This concentration is necessary for normal cellular activity. One biomembrane microparticle contains more than a million lipid molecules, which have dual characteristics: they are both hydrophobic and hydrophilic. As a rule, these mutually exclusive properties are non-equilibrium in nature, and therefore their functional purpose looks quite logical. Lipids in the cell are an effective natural regulator. The hydrophobic layer usually dominates and protects the cell membrane from the penetration of harmful ions.

Glycerophospholipids, phosphatidylethanolamine, phosphatidylcholine, cholesterol also contribute to cell impermeability. Other membrane lipids are located in tissue structures, these are sphingomyelin and sphingoglycolipid. Each substance performs a specific function.

Lipids in the human diet

Triglycerides - nature, are an efficient source of energy. acids are found in meat and dairy products. And fatty acids, but unsaturated, are found in nuts, sunflower and olive oils, seeds and corn grains. So that the level of cholesterol in the body does not increase, it is recommended to limit the daily rate of animal fats to 10 percent.

Lipids and carbohydrates

Many organisms of animal origin "stack" fats at certain points, subcutaneous tissue, in the folds of the skin, and other places. The oxidation of lipids in such fatty deposits is slow, and therefore the process of their conversion into carbon dioxide and water provides a significant amount of energy, almost twice as much as carbohydrates can provide. In addition, the hydrophobic properties of fats eliminate the need to use large amounts of water to promote hydration. The transition of fats into the energy phase occurs "dry". However, fats are much slower in terms of energy release and are more suitable for hibernating animals. Lipids and carbohydrates, as it were, complement each other in the process of the life of the body.

Lipids are the most important source of energy in the body. The fact is obvious even at the nomenclature level: the Greek "lipos" is translated as fat. Accordingly, the category of lipids combines fat-like substances of biological origin. The functionality of the compounds is quite diverse, which is due to the heterogeneity of the composition of this category of bio-objects.

What are the functions of lipids

List the main functions of lipids in the body, which are the main ones. At the introductory stage, it is advisable to highlight the key roles of fat-like substances in the cells of the human body. The basic list is the five functions of lipids:

reserve energy;
structure-forming;
transport;
insulating;
signal.

The secondary tasks that lipids perform in combination with other compounds include regulatory and enzymatic roles.

The energy reserve of the body

This is not only one of the important, but the priority role of fat-like compounds. In fact, part of the lipids is the source of energy for the entire cell mass. Indeed, fat for cells is an analogue of fuel in a car tank. The energy function of lipids is realized as follows. Fats and similar substances are oxidized in the mitochondria, breaking down to the level of water and carbon dioxide. The process is accompanied by the release of a significant amount of ATP - high-energy metabolites. Their reserve allows the cell to participate in energy-dependent reactions.

Structural blocks

At the same time, lipids perform a building function: with their help, the cell membrane is formed. The following groups of fat-like substances are involved in the process:

cholesterol - lipophilic alcohol;
glycolipids - compounds of lipids with carbohydrates;
Phospholipids are esters of complex alcohols and higher carboxylic acids.

It should be noted that in the formed membrane, fats are not directly contained. The resulting wall between the cell and the external environment is two-layered. This is achieved due to biphilia. A similar characteristic of lipids indicates that one part of the molecule is hydrophobic, that is, insoluble in water, the second, on the contrary, is hydrophilic. As a result, the bilayer of the cell wall is formed due to the ordered arrangement of simple lipids. Molecules turn their hydrophobic regions towards each other, while hydrophilic tails are directed inside and outside the cell.

This determines the protective functions of membrane lipids. First, the membrane gives the cell its shape and even maintains it. Secondly, the double wall is a kind of passport control point that does not allow unwanted visitors to pass through.

Autonomous heating system

Of course, this name is rather conditional, but it is quite applicable if we consider what functions lipids perform. The compounds do not so much heat the body as they keep the heat inside. A similar role is assigned to fatty deposits that form around various organs and in the subcutaneous tissue. This class of lipids is characterized by high heat-insulating properties, which protects vital organs from hypothermia.

Have you booked a taxi?

The transport role of lipids is considered a secondary function. Indeed, the transfer of substances (mainly triglycerides and cholesterol) is carried out by separate structures. These are linked complexes of lipids and proteins called lipoproteins. As you know, fat-like substances are insoluble in water, respectively, in blood plasma. In contrast, the functions of proteins include hydrophilicity. As a result, the core of a lipoprotein is an accumulation of triglycerides and cholesterol esters, while the shell is a mixture of protein molecules and free cholesterol. In this form, lipids are delivered to the tissues or back to the liver for removal from the body.

Secondary Factors

The list of already listed 5 functions of lipids complements a number of equally important roles:

enzymatic;
signal;
regulatory

Signal function

Some complex lipids, in particular their structure, allow the transmission of nerve impulses between cells. Glycolipids act as an intermediary in this process. No less important is the ability to recognize intracellular impulses, which is also realized by fat-like structures. This allows you to select from the blood the substances necessary for the cell.

Enzymatic function

Lipids, regardless of their location in the membrane or outside it, are not part of enzymes. However, their biosynthesis occurs with the presence of fat-like compounds. Additionally, lipids are involved in protecting the intestinal wall from pancreatic enzymes. The excess of the latter is neutralized by bile, where cholesterol and phospholipids are included in significant quantities.