Fats: structure, chemical composition, functions and applications. Fats: structure, functions, properties, sources for the body

Under general term lipids (fats) in science combine all fat-like substances. Fats are organic compounds that have different internal structure, but with similar properties. These substances are insoluble in water. But at the same time, they dissolve well in other substances - chloroform, gasoline. Fats are very widespread in living nature.

Fat Research

The structure of fats makes them an indispensable material for any living organism. The assumption that these substances have one hidden acid was made back in the 17th century by the French scientist Claude Joseph Jaurois. He discovered that the process of soap decomposition by acid is accompanied by the release of a fatty mass. The scientist emphasized that this mass is not the original fat, since it differs from it in some properties.

The fact that the structure of lipids also includes glycerol was first discovered by the Swedish scientist Karl Scheele. The full composition of fats was determined by the French scientist Michel Chevrel.

Classification

It is very difficult to classify fats based on their composition and structure, since this category includes a large number of substances that differ in their structure. They are united by only one characteristic - hydrophobicity. In relation to the process of hydrolysis, biologists divide lipids into two categories - saponified and unsaponifiable.

The first category includes a large number of steroid fats, which include cholesterol, as well as its derivatives: steroid vitamins, hormones, and bile acids. The category of saponified fats includes lipids called simple and complex. Simple ones are those that consist of alcohol, as well as fatty acids. This group includes Various types waxes, cholesterol esters and other substances. Complex fats contain, in addition to alcohol and fatty acids, other substances. This category includes phospholipids, sphingolipids and others.

There is another classification. According to it, the first group of fats includes neutral fats, the second - fat-like substances (lipoids). Neutral fats include complex fats with trihydric alcohol, such as glycerol, or a number of other fatty acids with a similar structure.

Diversity in nature

Lipoids include those substances that are found in living organisms, regardless of their internal structure. Fat-like substances can dissolve in ether, chloroform, benzene, and hot alcohol. In total, more than 200 different fatty acids are found in nature. However, no more than 20 types are widespread. They are found both in animal organisms and in plants. Fats are one of the main groups of substances. They have very high energy value- 37.7 kJ of energy is released from one gram of fat.

Functions

In many ways, the functions performed by fats depend on their type:

• Reserve energy. Substances of subcutaneous fat are the main source of nutrition for living beings during fasting. They also provide a power source for striated muscles, liver, kidneys.
• Structural. Fats are part of the cell membranes. Their main components are cholesterol and glycolipids.
• Signal. Lipids perform various receptor functions and participate in interactions between cells.
• Protective. Subcutaneous fat It is also a good thermal insulating substance for living organisms. It also provides protection to internal organs.

Structure of fats

One molecule of any lipid consists of an alcohol residue - glycerol, as well as three residues of various fatty acids. Therefore, fats are otherwise called triglycerides. Glycerin is a colorless and viscous liquid that has no odor. It is heavier than water and therefore mixes easily with it. The melting point of glycerol is +17.9 o C. Almost all categories of lipids include fatty acids. By chemical structure fats are complex compounds that include triatomic glycerol, as well as high molecular weight fatty acids.

Properties

Lipids undergo any reactions that are characteristic of esters. However they also have some characteristics, associated with their internal structure, as well as the presence of glycerol. According to their structure, fats are also divided into two categories - saturated and unsaturated. Saturated ones do not contain double atomic bonds, unsaturated ones do. The first include substances such as stearic and palmitic acid. Unsaturated acids include, for example, oleic acid. Besides various acids, the structure of fats also includes some fat-like substances - phosphatides and sterols. They are also more important for living organisms, as they participate in the synthesis of hormones.

Most fats are fusible - in other words, they remain liquid at room temperature. Animal fats, on the other hand, remain solid at room temperature because they contain large amounts of saturated fatty acids. For example, beef lard contains the following substances - glycerin, palmitic and stearic acids. Palmitic acid melts at a temperature of 43 o C, and stearic acid - at 60 o C.

The main subject in which schoolchildren study the structure of fats is chemistry. Therefore, it is advisable for the student to know not only the set of substances that are part of various lipids, but also to have an understanding of their properties. For example, fatty acids are the basis of vegetable fats. These are substances that get their name from the process of their isolation from lipids.

Lipids in the body

The chemical structure of fats consists of glycerol residues, which are highly soluble in water, as well as fatty acid residues, which, on the contrary, are insoluble in water. If you apply a drop of fat to the surface of water, the glycerol part will face it, and the fatty acids will be located on top. This orientation is very important. A layer of fat, which is part of the cell membranes of any living organism, prevents the cell from dissolving in water. Particularly important are substances called phospholipids.

Phospholipids in cells

They also contain fatty acids and glycerol. Phospholipids differ from other groups of fats in that they also contain phosphoric acid residues. Phospholipids are one of the most important components of cell membranes. Glycolipids, substances containing fats and carbohydrates, are also of great importance for a living organism. The structure and functions of these substances allow them to carry out various functions in nervous tissue. In particular, a large number of them are found in brain tissue. Glycolipids are located on the outer part of the plasma membranes of cells.

The structure of proteins, fats and carbohydrates

ATP, nucleic acids, as well as proteins, fats and carbohydrates belong to organic matter cells. They consist of macromolecules - large and complex molecules in their structure, which, in turn, contain smaller and simpler particles. There are three types of nutrients found in nature: proteins, fats and carbohydrates. They have different structures. Although each of these three types of substances belongs to carbon compounds, the same carbon atom can form different intraatomic compounds. Carbohydrates are organic compounds that consist of carbon, hydrogen, and also oxygen.

Feature Differences

Not only the structure of carbohydrates and fats differs, but also their functions. Carbohydrates are broken down faster than other substances - and therefore they can produce more energy. When present in the body in large quantities, carbohydrates can be transformed into fats. Proteins do not lend themselves to such transformation. Their structure is much more complex than that of carbohydrates. The structure of carbohydrates and fats makes them the main source of energy for living organisms. Proteins are those substances that are consumed as building material For damaged cells in organism. It’s not for nothing that they are called “proteins” - the word “protos” comes from the ancient Greek language and is translated as “the one who comes first.”

Proteins are linear polymers containing amino acids linked by covalent bonds. To date, they are divided into two categories: fibrillar and globular. In the structure of a protein, a primary structure and a secondary structure are distinguished.

The composition and structure of fats make them indispensable for the health of any living organism. In case of illness and loss of appetite, stored fat acts as an additional source of nutrition. It is one of the main sources of energy. However, excessive consumption fatty foods may impair the absorption of protein, magnesium, and calcium.

Application of fats

People have long learned to use these substances not only for food, but also in everyday life. Fats were used for lamps back in the days prehistoric era, they lubricated the runners with the help of which ships were launched into the water.

These substances are widely used in modern industry. About a third of all fats produced have a technical purpose. The rest are intended for consumption. Lipids are used in large quantities in the perfume industry, cosmetics, and soap making. Vegetable oils are mainly used for food - they are usually included in various products foods such as mayonnaise, chocolate, canned food. In the industrial sector, lipids are used to produce various types paints, medicines. Also fish fat added to drying oil.

Technical fat is usually obtained from waste food raw materials and is used for the production of soap and household products. It is also extracted from the subcutaneous fat of various marine animals. In pharmaceuticals, it is used to produce vitamin A. It is especially abundant in the liver cod fish, apricot and peach oils.

Fats are usually called a group of simple lipids that can be utilized by the human body and have common structural features. Fats, some lipids, and their components are responsible for many processes of normal human life. The functions of fats in the human body are very important

Functions of fats in the human body

Physiology, medicine, and biochemistry are intensively developing in parallel with the emergence of new instrumental research capabilities. Additional scientific data is constantly emerging, taking into account which the main functions of fats in the body can be presented in the proposed set.

• Energy. As a result of oxidative breakdown, 9 kcal of energy is indirectly formed from 1 g of fat, which significantly exceeds similar figures for proteins and carbohydrates.

• Regulatory. It has been established that as a result of metabolic reactions, 1 gram of fat in the body synthesizes 10 grams of “internal” water, which is more correctly called endogenous. The water we get from food and drinks is called “external”, exogenous. Water is an interesting substance that tends to form groups – associates. This is the difference between the characteristics of water that has undergone melting, purification, and boiling. The qualities of water synthesized in the body and supplied from outside differ similarly. Endogenous water must be synthesized, although its role has not yet been definitively established.

• Structural-plastic. Fats, alone or in combination with proteins and carbohydrates, participate in the formation of tissues. Essential has a layer of cell membranes consisting of lipoproteins - structural formations of lipids and proteins. Normal condition The lipid layer of the cell membrane ensures metabolism and energy. Thus, the structural and plastic functions of fats in the cell are integrated with the transport function.

• Protective. The subcutaneous layer of fat performs a heat-preserving function and protects the body from hypothermia. This is clearly seen in the example of children swimming in the cool sea. Babies with a small layer of subcutaneous fat freeze very quickly. Children with normal body fat can take water procedures much longer. Natural fat layer on internal organs protects them to some extent from mechanical influences. A small layer of fat normally covers many organs.

• Providing. Natural fats are always mixtures containing additional biological active substances. The role of fats in the body is to simultaneously provide components important for physiology: vitamins, vitamin-like compounds, sterols, and some complex lipids.

• Cosmetic and hygienic. The thin layer of fats present on the skin gives it firmness, elasticity, and protects it from cracking. The integrity of the skin, which does not contain microcracks, eliminates the entry of microbes.

Composition of fats

Fats are a group of substances consisting of one or more esters of high molecular weight carboxylic acids and alcohol - glycerol. Acids containing more than 4 carbon atoms are usually called higher fatty acids. The composition of fats varies depending on the source of excretion. In addition to these esters natural fats may contain small amounts of free high-molecular acids, flavoring substances, and pigments.

Based on the structural characteristics of acidic residues, the entire group is usually divided into saturated and unsaturated fats.

• In saturated fats, all the carbon atoms in the acid moiety are connected to each other only by single bonds. The smallest saturated acid found in fats is called butyric acid. During long-term storage, the ester bond may be destroyed, releasing acids. Free butyric acid has Strong smell, bitter taste. This is one of the reasons why the quality of fat deteriorates during long-term storage.

Important! Saturated higher carboxylic acids predominate mainly in animal fats.

The most common acids in natural fats are those with a greater number of carbon atoms and molecular weight than butyric acid, for example palmitic and stearic. Palmitic acid was first isolated from palm oil, its content reaching 50%. Stearic acid was first extracted from pig lard, which in Greek became the basis for the name of the acid. All saturated acids are poorly soluble in water, which complicates the functions of fats in the cell.

• Unsaturated fats are esters with a significant content of unsaturated high molecular weight acids: oleic, linoleic, linolenic, arachidonic. The term “unsaturated” is due to the presence of double bonds between the carbon atoms in such molecules, not single ones. In ordinary language we can say that such substances are not completely saturated with hydrogen. For ordinary consumers, it is not the structural features that are important, but the properties derived from them.

Important! All Not saturated fats found mainly in plants, they have low temperatures melting.

Under normal room conditions they are in a liquid state. Unsaturated acids are usually divided into groups: oleic acid and structurally similar, linoleic acid and the like, linolenic acid with homologues, arachidonic acid. Three latest groups have more than one double bond in a molecule. That's why they are called polyunsaturated fatty acids (PUFAs). The name of this complex of acids, vitamin F, is considered obsolete. Nowadays, linolenic acids are often called omega-3, while linoleic and arachidonic acids are called omega-6 acids.

• The structural function is to form cell membranes.

• The plastic role is performed during the formation connective tissue, surfaces of nerve fibers.

• The anti-sclerotic function comes down to the ability to remove excess cholesterol from the cavity blood vessels. Fats and cholesterol must enter the body in a strictly defined ratio. Excess cholesterol, coming from outside, in combination with those synthesized inside the body, can provoke changes in blood vessels.

• PUFAs increase the body's protective resources in relation to external influences, for example, viruses, microbes, unfavorable environmental factors.

• For normal operation In the cardiovascular system, it is important to have physiological indicators of blood clotting. PUFAs help normalize coagulation, which tends to increase with age.

• The scientific literature contains information about the ability of PUFAs to break down certain types of malignant cells.

• From arachidonic acid, with the participation of enzymes, prostaglandins are formed, which are classified as hormones and hormone-like substances. Prostaglandins have a diverse regulatory effect, in particular they indirectly improve the breakdown of fats in the body.

PUFAs are essential and should be included in the daily diet.

Sources of vegetable and animal fats

All food products obtained from animals and plants. Fats are no exception. Currently, more than 600 examples of various fats are known. The prevailing (more than 400) quantity is plant matter. 80 types are animal fats, more than 100 types are fats of water inhabitants. Sources of fats of plant and animal origin are varied, largely determined by culinary traditions, place of residence, climate, and income level of the population.

• Some fats are visible visually. These are butter and vegetable oils, lard, animal fats in meat, margarines.
• Some food fats are invisible. They are evenly distributed in meat, confectionery, dairy products, bread, fish, cereals, nuts.

How much fat do you need per day?

The need of each person should be determined taking into account many circumstances: age, type of activity, area of ​​residence, type of constitution. When playing sports, it is advisable to get advice from a specialist who can take into account everything individual characteristics. It is important to remember that animal fats and cholesterol come from food in parallel, and create a diet taking into account all components.

The answer to the question “How much fat should each person consume per day?” can be presented in the form of the following list:

• the total amount of all fats is 80-100 g;
• vegetable oils – 25-30 g;
• PUFA – 2-6 g;
• cholesterol – 1 g;
• phospholipids – 5 g.

The maximum amount of fat is found in refined vegetable oils(up to 99.8%), in butter - up to 92.5% fat, in margarines - up to 82%.

• It must be remembered that one of the methods for producing margarines is to saturate vegetable oils with hydrogen. The process is called hydrogenation. In this case, the product produces isomers that have a negative physiological effect - trans-isomers. IN Lately They use a different method for producing margarine - modification of vegetable oils. No harmful isomers are formed. Margarine was originally invented in France at the end of the 19th century to feed the poor and military. If possible, it is better to exclude margarine from the diet.

In dairy products the fat content can reach 30%, in cereals - 6%, in hard cheeses – 50%.

Given the importance of PUFAs, you should be aware of their sources

• The maximum amount of essential acids, primarily arachidonic acid, is found in fish fat. The ideal supplier of this acid is fish liver.
• Vegetable oils contain a lot of PUFAs. Content of linoleic acid in corn oil reaches 56%, in sunflower – 46%.
• The specific gravity of PUFAs does not exceed 22% in pork lard, chicken, goose fat. Olive oil contains 15% essential acids.
• Butter, most animal fats, and milk fats contain little PUFA, up to 6%.

In the list of mandatory components of natural fats recommended for daily nutrition, is cholesterol. We get the required amount by eating eggs, butter, offal. They should not be abused.

Phospholipids, which are classified as complex lipids, must be present in food. They promote the transportation of fat breakdown products in the body, their effective utilization, prevent fatty degeneration of liver cells, and normalize metabolism in general. Phospholipids are found in large quantities in egg yolk, liver, milk cream, and sour cream.

Excess fat in food

With excess fat in the daily diet, everything becomes deformed. metabolic processes. Excess fat in food leads to a predominance of accumulation processes over breakdown reactions. Fatty degeneration of cells occurs. They can't perform physiological functions, which provokes numerous violations.

Lack of fat in food

If there is little fat intake, the energy supply of the body is disrupted. Some part can be synthesized from the remnants of molecules formed during the utilization of proteins and carbohydrates. Essential acids cannot be formed in the body. Consequently, all the functions of these acids are not realized. This leads to loss of strength, decreased resistance, disruption of cholesterol metabolism, hormonal imbalance. An absolute lack of fat in food is rare. a lack of useful components fat may appear if the rules for combining dietary fats are not followed.

Alexey Dinulov, Elite - FPA Trainer

Fats are usually called a group of simple lipids that can be utilized by the human body and have common structural features. Fats, some lipids, and their components are responsible for many processes of normal human life.

Functions of fats in the body

Physiology, medicine, and biochemistry are intensively developing in parallel with the emergence of new instrumental research capabilities. Additional scientific data is constantly emerging, taking into account which the main functions of fats in the body can be presented in the proposed set.

• Energy. As a result of oxidative breakdown, 9 kcal of energy is indirectly formed from 1 gram of fat, which significantly exceeds similar figures for carbohydrates.

• Regulatory. It has been established that as a result of metabolic reactions, 1 gram of fat in the body synthesizes 10 grams of “internal” water, which is more correctly called endogenous. The water we get from food and drinks is called “external”, exogenous. Water is an interesting substance that tends to form groups – associates. This is the difference between the characteristics of water that has undergone melting, purification, and boiling. The qualities of water synthesized in the body and supplied from outside differ similarly. Endogenous water must be synthesized, although its role has not yet been definitively established.

• Structural-plastic. Fats, alone or in combination with proteins and carbohydrates, participate in the formation of tissues. Of utmost importance is the layer of cell membranes, consisting of lipoproteins - structural formations of lipids and proteins. The normal state of the lipid layer of the cell membrane ensures metabolism and energy. Thus, the structural and plastic functions of fats in the cell are integrated with the transport function.

• Protective. The subcutaneous layer of fat performs a heat-preserving function and protects the body from hypothermia. This is clearly seen in the example of children swimming in the cool sea. Babies with a small layer of subcutaneous fat freeze very quickly. Children with normal body fat can take water procedures much longer. The natural fatty layer on the internal organs protects them to some extent from mechanical stress. A small layer of fat normally covers many organs.

• Providing. Natural fats are always mixtures containing additional biologically active substances. The role of fats in the body is to simultaneously provide components important for physiology: vitamins, vitamin-like compounds, sterols, and some complex lipids.

• Cosmetic and hygienic. The thin layer of fats present on the skin gives it firmness, elasticity, and protects it from cracking. The integrity of the skin, which does not contain microcracks, eliminates the entry of microbes.

Composition of fats

Fats are a group of substances consisting of one or more esters of high molecular weight carboxylic acids and alcohol - glycerol. Acids containing more than 4 carbon atoms are usually called higher fatty acids. The composition of fats varies depending on the source of excretion. In addition to these esters, natural fats may contain small amounts of free high-molecular acids, flavoring agents, and pigments.

Based on the structural characteristics of acidic residues, the entire group is usually divided into saturated and unsaturated fats.

• In saturated fats, all the carbon atoms in the acid moiety are connected to each other only by single bonds. The smallest saturated acid found in fats is called butyric acid. During long-term storage, the ester bond may be destroyed, releasing acids. Free butyric acid has a pungent odor and bitter taste. This is one of the reasons why the quality of fat deteriorates during long-term storage.

Important! Saturated higher carboxylic acids predominate mainly in animal fats.

The most common acids in natural fats are those with a greater number of carbon atoms and molecular weight than butyric acid, for example palmitic and stearic. Palmitic acid was first isolated from palm oil, its content reaching 50%. Stearic acid was first extracted from pig lard, which in Greek became the basis for the name of the acid. All saturated acids are poorly soluble in water, which complicates the functions of fats in the cell.

• Unsaturated fats are esters with a significant content of unsaturated high molecular weight acids: oleic, linoleic, linolenic, arachidonic. The term “unsaturated” is due to the presence of double bonds between the carbon atoms in such molecules, not single ones. In ordinary language we can say that such substances are not completely saturated with hydrogen. For ordinary consumers, it is not the structural features that are important, but the properties derived from them.

Important! All unsaturated fats are found mainly in plants and have low melting points.

Under normal room conditions they are in a liquid state. Unsaturated acids are usually divided into groups: oleic acid and structurally similar ones, linoleic acid and the like, linolenic acid with homologues, arachidonic acid. The last three groups have more than one double bond in the molecule. That's why they are called polyunsaturated fatty acids (PUFAs). The name of this complex of acids, vitamin F, is considered obsolete. Nowadays, linolenic acids are often called omega-3, while linoleic and arachidonic acids are called omega-6 acids.

Physiological role of polyunsaturated fatty acids

• The structural function is to form cell membranes.

• The plastic role is performed during the formation of connective tissue, the surface of nerve fibers.

• The anti-sclerotic function comes down to the ability to remove excess cholesterol from the cavity of blood vessels. Fats and cholesterol must enter the body in a strictly defined ratio. Excess cholesterol coming from outside, in combination with that synthesized inside the body, can provoke changes in blood vessels.

• PUFAs increase the body's protective resources in relation to external influences, for example, viruses, microbes, and adverse environmental factors.

• For the normal functioning of the cardiovascular system, it is important to have physiological indicators of blood clotting. PUFAs help normalize coagulation, which tends to increase with age.

• The scientific literature contains information about the ability of PUFAs to break down certain types of malignant cells.

• From arachidonic acid, with the participation of enzymes, prostaglandins are formed, which are classified as hormones and hormone-like substances. Prostaglandins have a diverse regulatory effect, in particular they indirectly improve the breakdown of fats in the body.

PUFAs are essential and should be included in the daily diet.

Sources of vegetable and animal fats

All food products are obtained from animals and plants. Fats are no exception. Currently, more than 600 examples of various fats are known. The predominant (more than 400) amount is plant substances. 80 types are animal fats, more than 100 types are fats of water inhabitants. Sources of fats of plant and animal origin are varied, largely determined by culinary traditions, place of residence, climate, and income level of the population.

• Some fats are visible visually. These are butter and vegetable oils, lard, animal fats in meat, margarines.
• Some food fats are invisible. They are evenly distributed in meat, confectionery, dairy products, bread, fish, cereals, and nuts.

How much fat do you need per day?

The need of each person should be determined taking into account many circumstances: age, type of activity, area of ​​residence, type of constitution. When playing sports, it is advisable to get advice from a specialist who can take into account all individual characteristics. It is important to remember that animal fats and cholesterol come from food in parallel, and create a diet taking into account all components.

The answer to the question “How much fat should each person consume per day?” can be presented in the form of the following list:

• the total amount of all fats is 80-100 g;
• vegetable oils – 25-30 g;
• PUFA – 2-6 g;
• cholesterol – 1 g;
• phospholipids – 5 g.

In general, the fat content in daily ration should be about 30%. Residents of northern regions can increase the fat content in their daily diet to 40%.

The maximum amount of fat is contained in refined vegetable oils (up to 99.8%), in butter - up to 92.5% fat, in margarines - up to 82%.

• It must be remembered that one of the methods for producing margarines is to saturate vegetable oils with hydrogen. The process is called hydrogenation. In this case, the product produces isomers that have a negative physiological effect - trans-isomers. Recently, another method of producing margarine has been used - modification of vegetable oils. No harmful isomers are formed. Margarine was originally invented in France at the end of the 19th century to feed the poor and military. If possible, it is better to exclude margarine from the diet.

In dairy products, the fat content can reach 30%, in cereals - 6%, in hard cheeses - 50%.

Given the importance of PUFAs, you should be aware of their sources

• The maximum amount of essential acids, primarily arachidonic acid, is found in fish fat. The ideal supplier of this acid is fish liver.
• Vegetable oils contain a lot of PUFAs. The content of linoleic acid in corn oil reaches 56%, in sunflower oil – 46%.
• The specific gravity of PUFAs does not exceed 22% in lard, chicken, and goose fat. Olive oil contains 15% essential acids.
• Butter, most animal fats, and milk fats contain little PUFA, up to 6%.

The list of essential components of natural fats recommended for daily nutrition includes cholesterol. We get the required amount by eating eggs, butter, and offal. They should not be abused.

Phospholipids, which are classified as complex lipids, must be present in food. They promote the transportation of fat breakdown products in the body, their effective utilization, prevent fatty degeneration of liver cells, and normalize metabolism in general. Phospholipids are found in large quantities in egg yolk, liver, milk cream, and sour cream.

Excess fat in food

With excess fat in the daily diet, all metabolic processes are deformed. Excess fat in food leads to a predominance of accumulation processes over breakdown reactions. Fatty degeneration of cells occurs. They cannot perform physiological functions, which provokes numerous disorders.

Lack of fat in food

If there is little fat intake, the energy supply of the body is disrupted. Some part can be synthesized from the remnants of molecules formed during the utilization of proteins and carbohydrates. Essential acids cannot be formed in the body. Consequently, all the functions of these acids are not realized. This leads to loss of strength, decreased resistance, disruption of cholesterol metabolism, and hormonal imbalance. An absolute lack of fat in food is rare. A lack of beneficial fat components can occur if the rules for combining dietary fats are not followed.

Fats are one of the main nutritional components that enter our body with food. Lipids are very important for humans; without them it is impossible to imagine the normal existence of any living creature. The value of these substances is expressed in the fact that they are basic structural elements any cell membranes. In addition, these substances are universal sources of energy.

Functions of fats in a living body

They are indispensable for the human body, as they participate in several very important functions:

Plastic function. Some fats are the main component of prostaglandins, substances without which normal regulation is not possible blood pressure. White and Gray matter Almost 90 percent of nervous tissue consists of fats of various origins.

This is the second universal solvent. Those substances that are insoluble in water are successfully soluble in fats.

It should be noted that many organs of the human body are fixed in place by fat pads. When exhausted, some organs drop, which leads to various pathological situations.

Fat deposits are necessary for any body, as they are excellent heat insulators. When exhausted, the human body loses heat very quickly. This situation especially scary in childhood.

Lipids are the source of energy for our body. I note that when one gram is broken down, 9.3 kilocalories of heat are released. For comparison, one gram of carbohydrates can produce only 4.1 kilocalories.

Classification of fats

Chemists conventionally divide all fats into two categories: saturated and unsaturated. This separation is based on the amount of specific fatty acids. Let's see what are the differences between them?

Saturated fats are found primarily in foods of animal origin. Representatives of this category do not have any particular value for the body. These substances are practically not processed by our body and are the main building component of unfortunate fat deposits.

It is not for nothing that experts have dubbed such lipids the epithet “bad.” These food components contribute to an increase in blood cholesterol levels. As a result, the emergence of such dangerous diseases as atherosclerosis, ischemic disease heart, myocardial infarction. Of course, the consumption of these triglycerides should be limited to a minimum.

Unsaturated fats enter our body mainly from plant foods. This group lipids are figuratively called “good”. This epithet is not accidental, because they have a beneficial effect on most metabolic processes occurring in human body. Representatives of this group are divided into two more categories: monounsaturated and polyunsaturated.

Monounsaturated fats are the healthiest lipids. They consist of omega 9 fatty acids. positive influence difficult to overestimate. These substances participate in the processes of biosynthesis of proteins, substances without which the normal functioning of the body is unthinkable. Blood cholesterol levels are significantly reduced under their influence. The record holder for the content of representatives of this category is olive oil.

Polyunsaturated fats consist of omega 3 acids. These substances are the most liquid lipids, which have a positive effect on many systems of the human body, primarily the cardiovascular and urinary systems.

Under their influence, the permeability of the cell wall improves, moreover, they are completely processed in the body, and, therefore, are not components of the notorious fatty deposits. The “champions” in terms of the content of these substances are - linseed oil, sea ​​fish, walnuts.
The group of trans fats stands out among polyunsaturated fats. These are products of exclusively artificial origin, and they are found in margarine, potato chips and some others. Harmful effects of these lipids is expressed in damage to cell walls, which cannot but affect the functioning of all organs of the human body. You should avoid using them.

Fat metabolism

They begin to ferment small intestine. Under the influence of lipase, fat is broken down into its components: glycerol and fatty acids. Bile plays an important role in this process, since it contains natural detergents that facilitate the access of fermenting substances to the lipid molecule.

Next, the above components are absorbed into the intestinal wall, where fat resynthesis processes take place. IN lymphatic system substances called chylomicrons arrive, from which other fats are subsequently formed, necessary for the normal functioning of all organs and systems. The liver, the chemical laboratory of our body, plays an important role in this.

In turn, in each organ processes of biological utilization of fats occur with the formation of final products.

Conclusion

I looked at the functions of fats in the human body, what classification of food fats exists. Of course, fats are very important component food. Without them, the body will not function properly. However, if there is an excess of the latter, for example, if the balanced diet, V human body heavy ones are launched pathological processes. Of course, one should not completely exclude fatty foods from your diet, you may just need to limit your intake of certain foods. Be moderate in your diet and you will be healthy!

Once again I want to turn to the topic of essential nutrients and their role for our health. And we’ll talk about fats - what they are, what they mean for the body, the types of fats and their nutritional value, and, of course, we won’t ignore cholesterol and find out everything about good and bad cholesterol.

Fats, or lipids, are substances that are part of all living cells in our body and play an important role in the course of all life processes. Fats are complete nutrients.

Fats - importance for the body

• The main role of fats is to provide energy. Each gram of them, when oxidized in the body, provides more than 2 times more energy than the same amount of carbohydrates and proteins. And it is fat that helps the body use proteins and carbohydrates efficiently;
• supply the body with fatty acids, some of which are essential. Entering digestive tract, fats are broken down under the influence of appropriate enzymes, mainly in the small intestine. Decay products are absorbed through the intestinal walls into the lymph and enter the blood. Already in the intestinal wall, resynthesis of neutral fat occurs: from foreign fat, fat characteristic of this species body. This reserve fat is used up when there is a lack of food and helps to endure even prolonged fasting;
• supply the body with necessary fat-soluble vitamins groups A, D and E;
• lipids are part of hormones and have a significant effect on the regulation fat metabolism, affect cell permeability and the activity of many enzymes, thanks to the resulting lipid barrier, it is protected skin covering from drying out. Lipids – an important part immunochemical processes;
• fat is low in weight and conducts heat poorly. Thanks to this, being in subcutaneous tissue, protects the body from hypothermia;
• fats also perform a plastic function. Subcutaneous fat has significant elasticity, therefore it reduces the force of pressure during mechanical impacts on our organs and tissues, helps to float on water;
• The biological significance of fats is also determined by their influence on functional state nervous system, participating in the program nerve impulses, muscle contractions;
• fats are necessary for good brain activity, concentration, memory;
• Thanks to fats, digestibility improves and taste qualities food.

From the above, the importance of fats for the body becomes clear - they perform useful and necessary work, despite the fact that people have not favored them (fat) lately, and the word “cholesterol” is simply the source of all troubles.

Of course, not all fats are equally healthy, since nutritional value different fats is not the same. But at the same time, we need all fats and there is no such thing as “bad fat,” just excessive consumption of certain fats can harm our body. Let's try to deal with these fats.

Types of fats

Dietary fats mainly consist of fat-like substances - lipids and true neutral fat - triglycerides of fatty acids, which are divided into saturated and unsaturated. There are also monounsaturated and polyunsaturated fats.

1. Saturated fats are mainly fats of animal origin (milk fat, pork, beef, lamb, goose, ocean fish fat). From fats plant origin only palm and Coconut oil contain saturated fats.
2. Unsaturated fats are fats of vegetable origin (all types of vegetable oils, nuts, especially walnuts, avocados).
3. Monounsaturated fats are not essential fats, as our body is able to produce them. The most common is oleic, which is believed to help lower cholesterol levels. Contained in large quantities in olive oil, peanut, avocado oil.
4. Polyunsaturated fats are essential fatty acids that must be supplied with food, as they are not produced by the body on their own. The most famous are a complex of Omega-6 and Omega-3 acids. Truly “irreplaceable” - have mass beneficial properties and have a positive effect on both cardiac and mental activity, prevents the aging of the body, and eliminates depression. In some plant products These acids are available - nuts, seeds, rapeseed, soybean, flaxseed, camelina oil (by the way, these oils cannot be cooked), but the main source is sea fish and seafood.

Which fats are healthier?

As I said, there are no “bad” fats, but there is an opinion that saturated fats are not the healthiest. But you cannot completely abandon them. Just in different periods During a person’s life, their number should be different.

For example, in the first 2 years of a child's life, food should contain sufficient amounts of saturated fat. The proof of this is breast milk, in which 44% is saturated fat. In addition, it is, oddly enough, rich in cholesterol. Without enough fat, children will not develop well.

Yes and others age categories saturated fats are needed because they are a source of vitamins and stearic acid, which is involved in the synthesis of oleic monounsaturated acid, and it is very important for maintaining important vital functions body. You just need to reduce their number, since their excessive consumption increases the likelihood cardiovascular diseases, promotes the accumulation of “bad” cholesterol.

Unsaturated fats are more active, oxidize faster and are better used in energy metabolism.

Vegetable fats, being liquid, are very well absorbed. But not all animal fats, but only those with a melting point below 37 0. For example, melting point goose fat– 26-33 0, butter – 28-33 0, pork and beef fat – 36-40 0, lamb fat – 44-51 0.

If we compare the most common foods containing fat, the following facts emerge:

• the calorie content of vegetable oils is higher than that of butter and lard;
• olive oil contains almost no polyunsaturated fatty acids, but it is a record holder for the content of oleic acid, and it is not destroyed under the influence of high temperatures;
• sunflower oil contains polyunsaturated acids and quite a lot, but it contains too few omega-3 fats;
• high-quality butter contains vitamins A, E, B2, C, D, carotene and lecithin, which lowers cholesterol, protects blood vessels, stimulates the immune system, helps fight stress, and is easily digestible;
• lard - contains valuable arachidonic acid, which is generally absent in vegetable oils. This acid is part of cell membranes, is part of the heart muscle enzyme, and also participates in cholesterol metabolism;
• margarine - does not contain cholesterol, contains a large amount of unsaturated fatty acids and can completely replace butter, but provided that it does not contain trans fats (soft margarine).

We can only say unequivocally that trans fats (hydrogenated, saturated) are harmful - these are fats that are obtained as a result of converting liquid fats into solid ones. They are found in products quite often, since they are much cheaper than natural animal fats.

When talking about the importance of fats for the body, we cannot ignore the topic of cholesterol, as this question is constantly on everyone’s lips.

What is cholesterol

Cholesterol is a fat-like substance that is part of all cells and gives them hydrophilicity - the ability to retain water without losing their semi-liquid consistency.

Cholesterol is necessary for the proper functioning of the central nervous system. However, excess cholesterol in food is considered as negative factor in connection with the problem of atherosclerosis, which is based on a violation of fat metabolism. Cholesterol is deposited in the walls of blood vessels, which leads to a decrease in the lumen of blood vessels, and this can cause stroke and heart attack. Cholesterol deposition is associated with its level in the blood.

Bad and good cholesterol

But not total cholesterol threatens health, and the imbalance between two types, the so-called “good” and “bad” cholesterol. The predominance of “bad” cholesterol is mainly due to poor nutrition. But it helps a lot to increase the level of “good” cholesterol, during which the body intensively consumes cholesterol.

Yes, the benefits of fats are obvious, but how can we make them truly “friends” for our body?

We need to provide the body the right fats in the right quantity.

Fat consumption rate

• By physiological standards nutrition daily requirement in fat for an adult engaged in mental work – 84 -90 g. for men and 70-77 gr. for women.
• For those who do physical labor – 103 -145 g. for men and 81-102 gr. for women.
• In cold climates, the norm can be increased, but the limit for fat consumption is 200 grams. per day.

Not only quantity, but also quality also affects. Fats consumed in food must be fresh. Since they oxidize very easily, harmful substances quickly accumulate in them. For the same reason, they cannot be stored in the light.

I told you about the importance of fats for our body; they should be present in our diet. The main thing is to understand how much and what kind of fats we need so that they only provide benefits.

Elena Kasatova. See you by the fireplace.