LIPIDS - This is a heterogeneous group of natural compounds, completely or almost completely insoluble in water, but soluble in organic solvents and in each other, giving high molecular weight fatty acids during hydrolysis.
In a living organism, lipids perform a variety of functions.
Biological functions of lipids:
1) Structural
Structural lipids form complex complexes with proteins and carbohydrates, of which the membranes of the cell and cellular structures are built, and participate in a variety of processes in the cell.
2) Spare (energy)
Reserve lipids (mainly fats) are the body's energy reserve and are involved in metabolic processes. In plants, they accumulate mainly in fruits and seeds, in animals and fish - in subcutaneous adipose tissues and tissues surrounding internal organs, as well as in the liver, brain and nervous tissues. Their content depends on many factors (species, age, nutrition, etc.) and in some cases accounts for 95-97% of all lipids released.
Caloric content of carbohydrates and proteins: ~ 4 kcal / gram.
Caloric content of fat: ~ 9 kcal / gram.
The advantage of fat as an energy reserve, in contrast to carbohydrates, is hydrophobicity - it is not associated with water. This ensures the compactness of fat reserves - they are stored in anhydrous form, taking up a small volume. On average, a person's supply of pure triacylglycerols is approximately 13 kg. These reserves could be enough for 40 days of fasting in conditions of moderate physical activity. For comparison: the total reserves of glycogen in the body is about 400 grams; when starving, this amount is not enough even for one day.
3) Protective
Subcutaneous adipose tissue protects animals from cooling, and internal organs from mechanical damage.
The accumulation of fat in the body of humans and some animals is seen as an adaptation to irregular diets and to living in a cold environment. Especially large reserves of fat are found in animals that hibernate (bears, marmots) and are adapted to living in cold conditions (walruses, seals). The fetus has practically no fat, and appears only before birth.
Protective lipids of plants - waxes and their derivatives, covering the surface of leaves, seeds and fruits - constitute a special group in terms of their functions in a living organism.
4) An important component of food raw materials
Lipids are an important component of food, largely determining its nutritional value and taste. The role of lipids in various processes of food technology is extremely important. Spoilage of grain and its processing products during storage (rancidity) is primarily associated with a change in its lipid complex. Lipids isolated from a number of plants and animals are the main raw material for obtaining the most important food and industrial products (vegetable oil, animal fats, including butter, margarine, glycerin, fatty acids, etc.).
2 Classification of lipids
There is no generally accepted classification of lipids.
It is most expedient to classify lipids depending on their chemical nature, biological functions, as well as in relation to some reagents, for example, to alkalis.
According to their chemical composition, lipids are usually divided into two groups: simple and complex.
Simple lipids - esters of fatty acids and alcohols. These include fats , waxes and steroids .
Fats - esters of glycerol and higher fatty acids.
Waxes - esters of higher aliphatic alcohols (with a long carbohydrate chain of 16-30 C atoms) and higher fatty acids.
Steroids - esters of polycyclic alcohols and higher fatty acids.
Complex lipids - in addition to fatty acids and alcohols, they contain other components of various chemical nature. These include phospholipids and glycolipids .
Phospholipids Are complex lipids, in which one of the alcohol groups is associated not with FA, but with phosphoric acid (phosphoric acid can be combined with an additional compound). Depending on what kind of alcohol is included in the phospholipids, they are divided into glycerophospholipids (contain alcohol glycerin) and sphingophospholipids (contain sphingosine alcohol).
Glycolipids - these are complex lipids, in which one of the alcohol groups is associated not with FA, but with a carbohydrate component. Depending on which carbohydrate component is included in the glycolipids, they are subdivided into cerebrosides (contain a monosaccharide, disaccharide or a small neutral homooligosaccharide as a carbohydrate component) and gangliosides (contain an acidic hetero-oligosaccharide as a carbohydrate component).
Sometimes in an independent group of lipids ( minor lipids ) secrete fat-soluble pigments, sterols, fat-soluble vitamins. Some of these compounds can be classified as simple (neutral) lipids, while others are complex.
According to another classification, lipids, depending on their relationship to alkalis, are divided into two large groups: saponifiable and unsaponifiable.... The group of saponifiable lipids includes simple and complex lipids, which, when interacting with alkalis, hydrolyze to form salts of high molecular weight acids, called "soaps". The group of unsaponifiable lipids includes compounds that do not undergo alkaline hydrolysis (sterols, fat-soluble vitamins, ethers, etc.).
According to their functions in a living organism, lipids are divided into structural, storage and protective.
Structural lipids are mainly phospholipids.
Storage lipids are mainly fats.
Protective lipids of plants - waxes and their derivatives, covering the surface of leaves, seeds and fruits, animals - fats.
FATS
The chemical name for fats is acylglycerols. These are esters of glycerol and higher fatty acids. "Acyl-" means "fatty acid residue".
Depending on the number of acyl radicals, fats are divided into mono-, di- and triglycerides. If the molecule contains 1 fatty acid radical, then the fat is called MONOACYLGLYCERIN. If there are 2 fatty acid radicals in the molecule, then the fat is called DIACYLGLYCERIN. In humans and animals, TRIACYLGLYCERINS predominate (contain three radicals of fatty acids).
The three hydroxyls of glycerol can be esterified either with just one acid, for example palmitic or oleic, or with two or three different acids:
Natural fats contain mainly mixed triglycerides, including residues of various acids.
Since the alcohol in all natural fats is the same - glycerin, the differences observed between fats are solely due to the composition of fatty acids.
More than four hundred carboxylic acids of various structures have been found in fats. However, most of them are present only in small quantities.
The acids found in natural fats are monocarboxylic, built from unbranched carbon chains containing an even number of carbon atoms. Acids containing an odd number of carbon atoms, having a branched carbon chain or containing cyclic moieties are present in minor amounts. The exceptions are isovaleric acid and a number of cyclic acids found in some very rare fats.
The acids most common in fats contain 12 to 18 carbon atoms and are often referred to as fatty acids. Many fats contain small amounts of low molecular weight acids (C 2 -C 10). Acids with more than 24 carbon atoms are present in waxes.
The glycerides of the most common fats contain significant amounts of unsaturated acids containing 1-3 double bonds: oleic, linoleic and linolenic. Arachidonic acid containing four double bonds is present in animal fats; acids with five, six or more double bonds are found in fats of fish and marine animals. Most of the unsaturated lipid acids have a cis-configuration, their double bonds are isolated or separated by a methylene (-CH 2 -) group.
Of all the unsaturated acids found in natural fats, oleic acid is the most abundant. In very many fats, oleic acid accounts for more than half of the total mass of acids, and only a few fats contain less than 10%. Two other unsaturated acids, linoleic and linolenic, are also very widespread, although they are present in much lower amounts than oleic acid. Linoleic and linolenic acids are found in significant quantities in vegetable oils; for animal organisms, they are essential acids.
Of the saturated acids, palmitic acid is almost as widespread as oleic acid. It is present in all fats, with some containing 15-50% of the total acid content. Stearic and myristic acids are widespread. Stearic acid is found in large amounts (25% or more) only in the storage fats of some mammals (for example, in sheep fat) and in the fats of some tropical plants, for example, in cocoa butter.
It is advisable to divide the acids contained in fats into two categories: major and minor acids. The main acids of fat are acids, the content of which in fat exceeds 10%.
Physical properties of fats
As a rule, fats do not withstand distillation and decompose even when distilled under reduced pressure.
The melting point, and, accordingly, the consistency of fats depends on the structure of the acids that make up their composition. Solid fats, that is, fats that melt at a relatively high temperature, consist mainly of glycerides of saturated acids (stearic, palmitic), and oils that melt at a lower temperature and are thick liquids contain significant amounts of glycerides of unsaturated acids (oleic , linoleic, linolenic).
Since natural fats are complex mixtures of mixed glycerides, they melt not at a certain temperature, but in a certain temperature range, and they are preliminarily softened. For the characterization of fats, as a rule, is used solidification temperature, which does not coincide with the melting point - it is slightly lower. Some natural fats are solids; others are liquids (oils). The solidification temperature varies within wide limits: -27 ° C for linseed oil, -18 ° C for sunflower oil, 19-24 ° C for cow and 30-38 ° C for beef lard.
The solidification temperature of fat is due to the nature of its constituent acids: it is the higher, the higher the content of saturated acids.
Fats dissolve in ether, polyhalogenated derivatives, carbon disulfide, aromatic hydrocarbons (benzene, toluene) and gasoline. Solid fats are difficult to dissolve in petroleum ether; insoluble in cold alcohol. Fats are insoluble in water, but they can form emulsions, which are stabilized in the presence of surfactants (emulsifiers) such as proteins, soaps and some sulfonic acids, mainly in a slightly alkaline environment. Milk is a natural emulsion of protein-stabilized fat.
Chemical properties of fats
Fats enter into all chemical reactions characteristic of esters, but their chemical behavior has a number of features associated with the structure of fatty acids and glycerol.
Among the chemical reactions involving fats, several types of transformations are distinguished.
Lipids (Fats).Lipids- called a complex mixture of organic compounds (compounds with carbon C), with similar physical and chemical properties:
- insolubility in water.
- good solubility in organic solvents (gasoline, chloroform)Lipids are widespread in nature. Together with proteins and carbohydrates, they constitute the bulk of the organic matter of all living organisms, being an indispensable component of every cell. Lipids - the most important component of food, largely determines its nutritional value and taste.
In plants, they accumulate mainly in seeds and fruits. In animals and fish, lipids are concentrated in the subcutaneous fatty tissues, in the abdominal cavity and tissues surrounding many important organs (heart, kidneys), as well as in the brain and nervous tissues. There are especially many lipids in the subcutaneous adipose tissue of whales (25-30% of their mass), seals and other marine animals. In humans, the lipid content ranges from 10-20% on average.Types of lipids.
There are many types of fat classifications, we will analyze the simplest one, it divides them into three large groups:
- Simple lipids
- Complex lipids
- Derivatives of lipids.Let's analyze each group of lipids separately, what they include, and what they are for.
Simple Lipids.
1) Neutral fats (or just fats).
Neutral fats are made up of triglycerides.
Triglyceride - lipid or neutral fat, which contains glycerin combined with three fatty acid molecules.
Glycerol- chemical compound with the formula C3H5 (OH) 3, (colorless, viscous, odorless sweetish liquid.)
Fatty acid– natural or created compounds with one or more groups - COOH (carboxyl) that do not create cyclic bonds (aromatic), with the number of carbon atoms (C) in the chain at least 6.Triglycerides are made from the breakdown of dietary fats and are a form of fat storage in the human body. The majority of dietary fats (98%) are triglycerides. Fat is also stored in the body as triglycerides.
Types of fatty acids:
- Saturated fatty acids- contain only single bonds between carbon atoms with all other bonds attached to hydrogen atoms. The molecule combines with the maximum possible number of hydrogen atoms, therefore this acid is called saturated. They differ from unsaturated ones in that they remain solid at room temperature.
Foods that contain the most saturated fat are lard and fat, chicken, beef and lamb fat, butter and margarine. Foods rich in such fats include sausage, small sausages and other sausages, bacon, ordinary lean beef; sorts of meat called "marble"; chicken skin, bacon; ice cream, creams, cheeses; most of the flour and other confectionery products.- unsaturated fatty acids - contain one or more double bonds along the main carbon chain. Each double bond reduces the number of hydrogen atoms that can bind to the fatty acid. Double bonds also lead to a "bend" in fatty acids, which prevents bonding between them.
Unsaturated fatty acids are found in plant sources.They can be divided into two types:
1) monounsaturated - unsaturated fatty acids with one double bond. (for example, olive oil)
2) polyunsaturated - unsaturated fatty acids with two or more double bonds. (for example - linseed oil)There will be a separate big topic about edible fats, which examines in detail all their properties.
2) Waxes.
Waxes are fat-like substances of animal or vegetable origin, consisting of esters of monohydric alcohols and fatty acids.
Esters– compounds - COOH (carboxyl), in which the hydrogen atom in the HO group is replaced by an organic group.
Alcohols– –OH compounds bonded to the carbon atom.
In simple words, waxes are shapeless, plastic, easily softened when heated, melting in the temperature range from 40 to 90 degrees Celsius.
Beeswax is secreted by special glands of honey bees, from which bees build honeycombs.Complex lipids.
A complex lipid is a combination of a triglyceride with other chemicals.
There are three types of them.Phospholipids- glycerin combined with one or two fatty acids as well as phosphoric acid.
The cell membrane is composed of phospholipids. The most popular in food is lecithin.Glycolipids - compounds of fat and carbohydrate components. (Contained in all tissues, mainly in the outer lipid layer of plasma membranes.)
Lipoproteins- complexes of fats and proteins. (Blood plasma)
Derivatives of lipids.
Cholesterol is a wax-like fatty substance found in every cell of the body and in many foods. Some blood cholesterol is needed, but high levels can lead to heart disease.
A lot of cholesterol is found in eggs, fatty meats, sausages, fatty dairy products.With the general classification figured out, what functions do lipids perform?
Functions.
- Structural function.
Phospholipids are involved in the construction of cell membranes in all organs and tissues. They are involved in the formation of many biologically important compounds.
- Energy function.
When fat is oxidized, a large amount of energy is released, which goes into the formation of ATP. A significant part of the body's energy reserves is stored in the form of lipids, which are consumed when there is a lack of nutrients. Hibernating animals and plants accumulate fats and oils and use them to maintain vital processes. The high content of lipids in plant seeds ensures the development of the embryo and seedling before their transition to independent feeding. The seeds of many plants (coconut palm, castor oil plant, sunflower, soybean, rapeseed, etc.) are used as raw materials for the production of vegetable oil in an industrial way. carbohydrates and proteins.
- Protective and heat-insulating
Accumulating in the subcutaneous tissue and around some 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.
Lubricating and water repellent.
The wax covers the skin, wool, feathers, makes them more elastic and protects them from moisture. Leaves and fruits of many plants have a waxy coating.- Regulatory.
Many hormones are derived from cholesterol, such as sex hormones (testosterone at men and progesterone in women) and corticosteroids. Derivatives of cholesterol, vitamin D play a key role in the metabolism of calcium and phosphorus. Bile acids are involved in digestion processes. In the myelinated (non-conductive charge) sheaths of the axons of nerve cells, lipids are insulators during the conduction of nerve impulses.
- Source of metabolic water.
Oxidation of 100 g of fat gives approximately 105-107 g of water. This water is very important for some desert inhabitants, in particular for camels, which can go without water for 10-12 days: the fat stored in the hump is used for this very purpose. Bears, marmots and other hibernating animals receive the water necessary for life as a result of fat oxidation.
The main rule for maintaining health is an even distribution of the proportion of fat when serving food. In fact, a person needs fat, but he must control the amount of fat consumed. A person must himself determine the amount of fat that will be useful, and not harm health. Fat must be on the right track to avoid the unpleasant consequences associated with weight gain, leading to heart problems, hypertension, stroke, or even death. Therefore, it is worth paying attention to foods that help burn fat. Today we will consider 10 unknown facts about fat.
On average, the average person gains 1 g of excess fat every day.... In reality, people gain more body fat. More attention should be paid to nutrition and exercise. Draw conclusions: the more fat you consume, the sooner health problems begin.
Fat cells live for another ten years after the death of a person. However, they die from physical exertion. The problem is that brain cells are constantly dying and renewing, but if fat cells take their place, memory problems occur, especially in the elderly.
8. Source of calories
In fact, fat is an irreplaceable source of calories for the body. It is vital for the maintenance of all vital processes in the body. It is worth remembering that being overweight leads to health problems.... The main rule is to choose the right foods with enough calories for the body to function.
7. Fat enhances flavor
Most preservatives and flavor enhancers are fat-based... When you mix them with food, they have a pleasant and inviting aroma and taste. If you like to cook, try adding meat or animal fat to the dish, the smell and taste of the dish will immediately change.
Fat is a kind of absorbent for vitamins. People who constantly take vitamins notice that the effect of vitamins is weaker after eating. Especially if the vitamins are in a soluble form.
5. Women need fat more than men
First of all, the great need for fats in women is associated with nature. A woman is a mother, in order to conceive a child, the body needs strength to carry a child and raise him in the womb, the body burns calories and fats, and, finally, after the birth of a child, a woman breastfeeds, and the basis of milk is lactose and fat. Fat reserves in a woman's body are explained by the fact that the body stores energy for the expectant mother. Therefore, many women lose weight after breastfeeding.
There are two types of fat. Figuratively they are called good and bad. Good fat is referred to as unsaturated fat, such fats are necessary for the human body. They are found in lean white meats and steamed foods such as fish. Bad fats are fatty meats, chicken skin, or dairy products. The consumption of these foods leads to high cholesterol and heart problems.
Since fat contains a high level of calories, they are stored for energy.... Consuming 1 gram of fat equals 9 calories.
2. Fat storage
Fat, which is essential for health, is stored in the muscles, bone marrow and organs of the nervous system. It is essential for the production of hormones and boosting immunity. Subcutaneous fat is an indicator that it's time to lose weight. Fat is found in foods that increase muscle mass.
Women should maintain 13 to 17% body fat which are usually stored in the thighs, chest, thighs, and abdomen. In men, fat is stored in the belly. They must maintain a body fat percentage of 3 to 5%, which is significantly less than that of women.
What are lipids?
Lipids are a series of organic substances that are part of all living cells. It also includes fats and fat-like substances contained in the cells and tissues of animals as part of adipose tissue, which plays an important physiological role.
The human body itself is able to synthesize all the main lipids. Only fat-soluble vitamins and essential polyunsaturated fatty acids cannot be synthesized in the body of animals and humans. Basically, lipid synthesis occurs in the liver and epithelial cells of the small intestine. A number of lipids are characteristic of certain organs and tissues, the rest of the lipids are present in the cells of all tissues. The amount of lipids contained in organs and tissues is different. Most lipids are found in adipose and nervous tissue.
The lipid content in the human liver varies from 7 to 14% (dry weight). In the case of liver diseases, such as fatty degeneration of the liver, the lipid content in the liver tissue reaches 45%, mainly due to an increase in the amount of triglycerides. Plasma lipids are contained in combination with proteins, and in this composition they are transported to other organs and tissues.
Lipids perform the following biological functions:
1. Structural. In combination, phospholipids with proteins form biological membranes.
2. Energy. In the process of fat oxidation, a large amount of energy is released, and it is this energy that goes into the formation of ATP. Most of the body's energy reserves are stored precisely in the form of lipids, and are consumed in the event of a lack of nutrients. So, for example, animals go into hibernation, and previously accumulated fats and oils are used to maintain vital functions. Due to the high lipid content in plant seeds, the embryo and seedling develop until they feed on their own. The seeds of such plants as coconut palm, castor oil plant, sunflower, soybean, rapeseed are the raw materials from which vegetable oil is made industrially.
3. Heat insulating and protective. It is deposited in the subcutaneous tissue and around organs such as the intestines and kidneys. The resulting layer of fat protects the animal's body and its organs from mechanical damage. Since subcutaneous fat has low thermal conductivity, it perfectly retains heat, this allows animals to live in cold climates. For whales, for example, this fat contributes to buoyancy.
4. Lubricating and water repellent... There is a layer of wax on leather, wool and feathers that leaves them elastic and protects them from moisture. There is such a layer of wax on the leaves and fruits of various plants.
5. Regulatory. Sex hormones, testosterone, progesterone and corticosteroids, as well as others, are derivatives of cholesterol. Vitamin D, a derivative of cholesterol, plays an important role in calcium and phosphorus metabolism. Bile acids are involved in digestion (emulsification of fats), as well as in the absorption of higher carboxylic acids.
The source of metabolic water formation is lipids. So to get 105 grams of water, you need to oxidize 100 grams of fat. For the inhabitants of the deserts, such water is vital, for example, for camels, which have to do without water for 10-12 days, they have such fat deposited in the hump and consumed in order to obtain water. The fat oxidation process is very important for hibernating animals such as marmots, bears, etc.
Lipids - what are they? Translated from Greek, the word "lipids" means "small particles of fat". They are groups of natural organic compounds of an extensive nature, including fats themselves, 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, while complex lipids contain high molecular weight 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 the body's energy reserve and the provision of the water-repellent properties of the skin, coupled with thermal insulation protection. Some fatty acid-free substances are also classified as lipids, such as terpenes. Lipids are not susceptible to the action of the aquatic environment, but they easily dissolve 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 are they?" 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 general 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 an essential 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, interconnection and exchange of signals in the intercellular environment are not complete without fatty acids.
Lipids - what are they when viewed from the perspective of spontaneously emerging steroid hormones, phosphoinositides and prostaglandins? This is, first of all, the presence in 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 a complex with albumin, while lipoproteins, soluble in water, are transported in the usual manner.
Lipid classification
The categorization of biological compounds is a process that has some controversial issues. Lipids, due to their biochemical and structural properties, can be equally assigned to different categories. The main classes of lipids include simple and complex compounds.
Simple ones include:
- 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-atom alcohol.
Complex lipids:
- Phospholipid compounds - with the inclusion of nitrogenous components, glycerophospholipids, ophingolipids.
- Glycolipids are 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 a material for cell membranes. Participate in the transport of various substances along the periphery of the body. Fatty layers based on lipid structures help protect the body from hypothermia. They have the function of energy storage "in reserve".
Fat reserves are concentrated in the cytoplasm of cells in the form of droplets. Vertebrates, including humans, have special cells - adipocytes, which are capable of containing a lot of fat. The placement of fat accumulations in adipocytes is due to lipoid enzymes.
Biological functions
Fat is not only a reliable source of energy, it also has thermal insulating properties, aided by biology. At the same time, lipids allow achieving several useful functions, such as natural cooling of the body or, conversely, its thermal insulation. In the northern regions, 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 the 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 essential for normal cellular activity. One microparticle of the biomembrane contains more than a million lipid molecules that have dual characteristics: they are simultaneously hydrophobic and hydrophilic. As a rule, these mutually exclusive properties are of a non-equilibrium nature, and therefore their functional purpose looks quite logical. Cell lipids 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 has a specific function.
Lipids in the human diet
Triglycerides - nature, are an effective source of energy. acids are found in meat and dairy products. And fatty acids, but unsaturated, are found in nuts, sunflower and olive oil, seeds and corn grains. To prevent an increase in cholesterol levels in the body, it is recommended to limit the daily intake of animal fats to 10 percent.
Lipids and carbohydrates
Many organisms of animal origin "store" fats at certain points, subcutaneous tissue, folds of the skin, and other places. The oxidation of lipids of such fat deposits is slow, and therefore the process of their transition to carbon dioxide and water allows you to get a significant amount of energy, almost twice as much as carbohydrates can provide. In addition, the hydrophobic properties of fats eliminate the need for large amounts of water to stimulate hydration. The transition of fats to the energy phase occurs "dry". However, fats act much more slowly 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 body's vital activity.
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