The role of fats in nutrition. The importance of fats in nutrition

A balanced ratio of proteins, fats, carbohydrates supplied with food is the key proper nutrition and formation of a healthy beautiful body.

Perhaps fats cause the most large quantity questions. For many, their very name is associated with something unhealthy. However, not all of them are harmful; moreover, without some types of fats, an active sports lifestyle will lead to exhaustion of the body. The attitude towards them is most often negative, but to what extent can fats be reasonably considered harmful to the body and its functioning?

What are fats and their types - harmful and healthy?

Fats are natural complex organic compounds. From a chemical point of view, these are esters of the trihydric alcohol glycerol and carboxylic acids. From point of view ordinary people fats are complex chemical substances with a large molecule that, when broken down, releases great amount energy. However, for the effective release of energy from fats, the body must be saturated not only with them, but also with carbohydrates and oxygen.

Today the following classification of natural fats is accepted:

• Saturated or animal. These are the so-called harmful fats, an excess intake of which leads to various complications from the heart, blood vessels, and liver.
• Unsaturated or vegetable fats are trivially called “healthy”. They, in turn, are divided into mono- and polyunsaturated. Monounsaturated fats have a small molecule, so they are more easily broken down into their components - water and carbon dioxide, releasing almost twice as much energy as the same amount of carbohydrates. Polyunsaturated fats are somewhat more difficult to break down, but they are practically the only source of essential acids in the body. In addition, they are resistant to heat treatment.

The importance of fats for the body

The beneficial functions of fats in the body are as follows:

• When fats are broken down, a large amount of energy is released.
• Participate in the life of epithelial cells.
• Are building material for human brain cells.
• Some vitamins, when entering the human body, are not absorbed without fat.
• They are sources of essential acids.

Fat intake standards for adults

The average rate of fat consumption by an adult is calculated based on the ratio of 1 g of fat per 1 kg of body weight, i.e. the approximate rate of their consumption per day for men is 80–100 g, for women 50–60 g. At least 80% of this quantities should be vegetable fats. Moreover, unsaturated monocompounds should account for more than half of the total daily intake of healthy fats.

Fat consumption during sports and harmful unnatural fats

Sports enthusiasts should increase the content of vegetable fats in their diet to 90% of their daily fat intake. The remaining 10% should come from animal fats.

In addition to the classification of natural fats described above, there are two more types of harmful fats, the appearance of which is due to the development of society. We are talking about oxidized (transgenic) fats and trans fatty acids. This is an integral component of fast food and high-calorie sweets:

• deep-fried dishes;
• shortbread cookies, biscuits, creams;
• sauces, including ketchup and mayonnaise.

Any person should limit the consumption of these “goodies”, because the price for loving them is too high: heart disease, obesity, diabetes, oncology. Athletes should avoid these products altogether; coupled with training, they place unnecessary stress on the body.

Fats in foods

Vegetable fats:

• Monounsaturated fats (Omega-9) reduce general level"bad" cholesterol. They contain olive, peanut, hazelnut, sesame oils, avocado, pistachios, hazelnuts, cashews, sesame seeds, and olives.
• Polyunsaturated fats. Sources of Omega-3s that are beneficial for the cardiovascular system are fatty sea fish, shrimp, oysters, lake trout, flax-seed and oil, hemp seed and oil, pine nuts and walnuts. Omega-6 is found in corn, sunflower, soybean oils, as well as seeds.

Sources of animal fats:

• Butter and milk fats.
• Animal fats, for example, beef fat, lard.
• Palm oil.

Animal fats contain “bad” cholesterol, and the liver suffers from their excessive consumption. Such fats are difficult to digest, creating a greater burden on the body. Dairy fats put less strain on the body; if it is difficult to get by with only vegetable fats, you can consume them in small quantities butter. Just remember that it cannot be stored or heated for a long time! All animal fats are unsuitable for cooking!

Fats and weight loss

Fats are high in calories, but you can’t completely stop eating them. With a deficiency of fat, first of all, brain cells will begin to suffer and deteriorate. appearance skin.

Should choose the right strategy fat consumption:

• Reduce their consumption to a physiological minimum.
• When planning your meals, remember that fats are an integral part of many other foods.
• Consume only vegetable fats.
• Buy only virgin oils.

A healthy diet is the first step towards developing healthy body and a beautiful figure. Remember that the human body is complex mechanism, in which everything is interconnected. Intake of proteins, fats, and carbohydrates with food is necessary for them to perform their beneficial functions for the body. However, an excess or deficiency of each element can lead to the development of serious complications, especially for people who have regular physical exercise. Have a balanced and healthy diet!

Healthy eating and watching your figure have been fetishes of recent decades. People who want to be healthy and beautiful spend hours in gyms and carefully calculate the caloric content of their food, sometimes, in order to quickly achieve results, rushing to extremes.

We will not talk now about dubious strict diets with the complete exclusion of certain substances from the diet (for example, a diet without fat or a diet with low content fats), which a sane person is unlikely to consume. Let's talk about nutritious nutrition, proper nutrition, including fats, proteins, carbohydrates, and in a rational ratio. Let's start, perhaps, with fats, which are often terribly afraid of everyone who is fighting for a slim figure.

There is no need to be afraid, you need to have information! If you sincerely still believe that butter is evil, from vegetable oils you only need to use expensive olive oil, and a low-fat diet is a direct path to healthy weight loss, our series of articles is just for you. So, meet fats and oils

The main thing you must understand is that fats in the diet are necessary for the normal functioning of the body. Problems with them arise from those who either consume the wrong fats, or in the wrong quantities, or (as in a popular joke) do not know how to cook them.

Yes, fats are more than twice as caloric as carbohydrates, but this does not mean that those losing weight should give them up altogether!

Why does the body need fats in general? Their main functions are energetic and structural. Simply put, fats are definitely included in the composition cell membranes and are the most important source of energy(if one gram of carbohydrates is equivalent to 4 kcal, then one gram of fat is already 9 kcal). In addition, they contain important fat-soluble vitamins (A, D, E, K), promote better absorption of many substances and are directly involved in many processes occurring in our body. The right oils can even perform healing functions! And we are not yet considering the “side” properties of fats, such as thermal insulation of the body, “storing” water, improving the taste of food, etc.

Why does the body need external fats? Because the body itself is not able to fully provide itself with them and simply must receive them from food. There is even a very telling scientific term - “essential fatty acids”, that is, there is nothing to replace them in the diet, period.

Fatty acids and their properties

What types of fats are there and are they all equally important and beneficial for the body? As you know, dietary fats can be vegetable(sunflower, olive, linseed oil etc.) and animal(lard, butter, fish oil, etc.) origin. We will talk about each of them in more detail in separate articles, but now it is important for us to learn basic general information.

The quality composition of the fats consumed is of great importance. Any fats consist of special organic “building blocks” - fatty acids. Those in their own way chemical structure are divided into saturated (in them the bonds between carbon atoms are extremely saturated, so they are little active in the biological sense) and unsaturated (they contain one or more unsaturated (double) bonds in the molecule, at the place of which hydrogen can attach - they react more easily with other substances in body at the site of their fragile double bond). The latter, in turn, are divided into mono- and polyunsaturated according to the number of double bonds.

Saturated acids(for example, stearic and palmitic) for the most part are easily synthesized in the human body and are difficult to digest, so their excess intake from the outside is undesirable and leads to the accumulation of calories. Unsaturated acids are absorbed much easier and perform more important functions. For a full-fledged existence, the body needs both.

Several acids from the unsaturated group are the most important essential (omega fatty acids) that the body cannot synthesize itself, but needs them. These are polyunsaturated omega-3(linolenic acid) and omega-6(linoleic acid). The value of omega-3 is difficult to exaggerate - the health of the cardiovascular and nervous systems, brain function and condition directly depend on it. mental sphere, normal development fetus in pregnant women. In the vast majority of cases, unfortunately, today the average “Western” diet is desperately lacking omega-3. Omega-6 is also extremely important, indirectly strengthening immune system, participating in the formation of prostaglandins, regulating the functioning of the gastrointestinal tract and cardiovascular system, allergic reactions.

It is interesting that derivatives of these two acids have opposite directions of action: some narrow the lumen blood vessels and bronchi, increase inflammation and thrombus formation, while others dilate the bronchi and blood vessels, suppress inflammation, and reduce thrombus formation.

(There is an assumption that a sharp shift in the ratio of polyunsaturated fatty acids towards omega-6 last decades caused an increase in the risk of occurrence and widespread inflammatory diseases and allergies.)

So, fats of animal origin (meat and lard, fish, poultry, dairy products) contain mainly saturated acids, while vegetable fats (oils, nuts, cereals) are mostly unsaturated. But don’t think that this means that in pursuit of health you should only consume vegetable fats! Only a balanced diet can be considered optimal, including all the main types of fatty acids, without “biases” in one direction or another.

Yes, almost everything animal fats contain the most important phosphatides and sterols that are actively involved in various processes vital activity (we will talk about their importance for the body a little later in a separate article), some are very significant unsaturated arachidonic and oleic (omega-9) acids. Animal fats are also sources of essential fat-soluble vitamins A and D.

Sea fish and animals (especially from northern latitudes), and fish oil are rich in unsaturated linolenic acid. Lard and butter are the champions in the content of saturated fatty acids among animal fats, slightly less than in pork, fatty sausages and cheeses. There are many phospholipids in poultry and fish, cheese, and eggs. Arachidonic acid is found in eggs and offal, oleic acid is found in pork and beef fat. Eggs, cheeses, and butter are rich in cholesterol.

Vegetable fats in turn, they are the most important sources of essential unsaturated fatty acids; they are rich in phosphatides, that is, they also supply the body with valuable substances that are involved in a number of significant processes. Some vegetable oils also contain saturated fatty acids (palm and coconut, for example).

The leaders in the content of well-absorbed vitamin E are walnut seed oil and wheat germ oil. Flaxseed and flaxseed oil, as well as camelina oil, are rich in omega-3 acid; the main source of omega-6 in a normal diet is sunflower oil. Not essential, but also very important is the unsaturated fatty acid omega-9, which is abundant in olive oil.

An intermediate place between animal and vegetable fats is occupied by margarine, whose composition includes vegetable and animal fats, milk, salt and egg yolk, as well as all kinds of additives “to the taste” of the manufacturer - dyes, preservatives, flavorings Margarines are very different in production technology and composition, so in general it is impossible to speak unambiguously about their nutritional value and benefits in principle.

(Now you can appreciate, for example, the healthy Mediterranean diet that everyone hears about, with an abundance of fish and olive oil, and the diet of the average Belarusian with a clear bias towards meat and sunflower oil, that is, with a clear excess of omega-6 compared to omega-3.)

Part 2. Fats: too little or too much? How to eat fats?

What happens if you get too little fat from your diet? No, not the desired quick weight loss, but a lot of problems in the body. For example, lethargy and apathy, metabolic disorders of certain substances, a slowdown in detoxification processes, a sharp decrease in the amount of certain enzymes and hormones, deterioration of the condition of the skin and hair, an increased risk of all kinds of inflammation With a lack of fat intake, the body rearranges its work, trying to make up for the deficiency through its own synthesis, in vain spending additional strength and energy, and also getting a result that is not quite of the same quality. In very advanced cases, we can already talk about the development of atherosclerosis, diseases of the musculoskeletal system and nervous system, about disruption of blood supply.

What happens if you eat too much fat in your diet? First of all, a violation digestive processes(bile does not have time to emulsify all the incoming fat). Also, deterioration in the absorption of protein and some macroelements, increased need for vitamins, disorders fat metabolism. This leads to an increase in body weight with all that it entails, sharp increase risk of developing atherosclerosis, diabetes mellitus, cholelithiasis

That is, any extreme is unacceptable. From all of the above, it becomes clear that the body needs fats, but fats must be of high quality and consumed in moderation.

How much fat should you consume? But here there will be no general answer, since the amount of fat that should come from food depends on many factors: your age, health status, amount of physical and mental activity, even those around climatic conditions! The more energy the body expends, the more fat is needed to replenish it. Very average daily norm fat consumption by a healthy adult ranges from 1-1.5 g per kilogram of weight (about 30% of a person’s daily caloric intake) - and taking into account the body’s need for polyunsaturated fatty acids, a third of these approximately seventy to one hundred grams should be vegetable oils and two thirds are animal fats. With age, it is worth reducing the total amount of fat consumed plus changing the ratio of vegetable and animal fats in the diet to approximately 50/50.

How much fat does the body need? There are several methods for determining this amount, but none of them can be considered ideally correct. Most nutritionists agree that a woman's body fat should be 18-25%.

The simplest, although approximate, result is obtained by measuring body volume: the waist volume should be divided by the chest volume and separately by the hip volume. If both figures obtained exceed 0.8, then the amount of fat in the body is too high.

How to properly consume fats? The nutritional value of different fats varies and largely depends on the digestibility of fat by the body. It, in turn, depends on the melting temperature of a particular fat - the higher this temperature, the worse the fat is digested and absorbed. To fats with high temperature melting properties include, for example, lamb and beef fat; low melting properties include many vegetable fats liquid fats, butter, lard, margarines.

Improper storage, high-temperature cooking, as well as deep technical processing can “spoil” even the most valuable fats. When exposed to light or stored for too long, fats become rancid and oxidize; consuming such a product has an adverse effect on the body. Intensive heat treatment leads to the destruction and oxidation of fats and their beneficial components(the fat in the frying pan is “smoking,” which means it is already being destroyed) with the parallel formation and release of unhealthy substances like carcinogens, the neutralization of which requires a huge amount of effort and resources of the body. Strong technological processing with the aim of increasing shelf life, neutralizing the color or strong natural smell of the oil often transforms the structure of the product so much that it is no longer necessary to talk about any of its benefits at all.

For example, unrefined vegetable oil and butter are low-processed fats and are much more healthy than, for example, margarine, obtained by hydrogenation with the formation of harmful trans-isomers of fatty acids, or refined vegetable oil (we will also talk about this in more detail in the relevant articles) .

Caloric content of animal fats and plant origin approximately the same. Do not forget also that when mentioning the daily value, we are not talking about fats in pure form- spoons of vegetable oil or cubes of butter. So-called “hidden” fats are found in many foods, especially confectionery and fast food, and can greatly disrupt your calorie balance if ignored. In addition, we should not forget that factors such as overuse alcohol and “highly processed” fats can impair the activity of enzymes responsible for fat metabolism.

So, we hope that from the first article in the series you understood that fats are in complete healthy diet are extremely necessary. You just need to learn how to choose and use them correctly.

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January 14, 2018 Now the world is experiencing a boom in “superfoods” - hyper-healthy foods, a pinch of which can cover almost daily norm necessary for the body nutrients. The editors of the portal site decided to conduct their own research on the popularity and usefulness of chia, including in it real experience readers of the portal and Facebook friends, including Maria Sanfirova, the author of this review and part-time vegetarian with decent experience...

January 09, 2018

Fats (lipids) - these are complex organic compounds consisting of triglycerides and lipoid substances (phospholipids and sterols). Triglycerides contain glycerol and fatty acids (FAs) connected by ester bonds. Fatty acids are the main components of lipids (about 90%), it is their structure and characteristics that determine the properties of various types of dietary fats. Fatty acids that make up dietary fats are divided into three large groups:

Saturated FA (SFA) - all carbon atoms are connected by single covalent bonds (palmitic, stearic, butyric, caproic acids, etc.);

Monounsaturated FAs (MUFAs) have one double bond (oleic, palmitooleic, erucic acids);

Polyunsaturated FAs (PUFAs) have several double bonds and differ in the location of the first double bond from the terminal methyl group:

Omega 3 (ω-3) - double bond at the 3rd carbon atom (linolenic and arachidonic acids)

Omega 6 (ω-6) - double bond at the 6th carbon atom ( linoleic acid).

By their nature, dietary fats can be animal or vegetable. Vegetable oils (sunflower, corn, cottonseed, flaxseed, soybean, hemp, etc.) contain mainly unsaturated fatty acids, and animal fats (lamb, beef, etc.) contain mainly saturated ones. High content in vegetable oils, unsaturated fatty acids give them liquid state of aggregation(with the exception of palm oil) and determines their nutritional value.

Fats play a significant role in the functioning of the body and perform many functions.

Energy function - lipids are the second most important sources of total energy coming from food after carbohydrates, while having the maximum caloric coefficient among energy-carrying nutrients (1 g of fat gives the body 9 kcal).

Plastic function - lipids are part of cell membranes and cellular structures.

Protective function- adipose tissue, enveloping human organs, actually protects them from mechanical shocks and injuries, softening and cushioning the results external influences. Adipose tissue fixes internal organs and neurovascular bundles. Fat is part of the secretion sebaceous glands, protecting the skin from drying out;

Thermoregulatory function - due to extremely low thermal conductivity, fat deposited in subcutaneous fatty tissue serves as a heat insulator, protecting the body from heat loss. When the body cools, lipids are used to generate heat.

Dietary fats are direct sources or precursors for the formation of steroid hormones, calciferol (vitamin D3) and regulatory cellular compounds in the body.

With dietary fats, other compounds of lipid nature or lipophilic structure also enter the body: phosphatides, sterols, fat-soluble vitamins.

Unsaturated fatty acids. The main representative of monounsaturated fatty acids in the diet is oleic acid. Its main food sources are olive and peanut oil, pork fat.

Polyunsaturated fatty acids (PUFAs) are divided into two classes: omega-3 and omega-6. They cannot be synthesized in the body, they belong to irreplaceable (essential) substances and must be supplied with food.

The most important PUFAs of the ω-3 class are alpha-linolenic acid, from which long-chain ω-3PUFAs: eicosapentaenoic acid and docosahexaenoic acid can be synthesized in cells. With aging of the body and some diseases, the ability to synthesize DHA and EPA is completely lost.

ω-6 polyunsaturated fatty acids include linoleic acid, which can be converted into arachidonic acid in the body. Arachidonic acid is essential in the body only when there is a deficiency of linoleic acid.

In the body, PUFAs perform a number of important functions, namely:

Bioregulatory - are the basis for hormone-like substances - eicosanoids, which regulate numerous biochemical processes in cells and tissues, reduce the activity of inflammation, and have an immunomodulatory effect (prostaglandins, leukotrienes and thromboxanes).

Plastic - they are part of the membranes of body cells (brain, blood vessels, heart, retina and sperm).

They affect blood clotting by reducing platelet aggregation, reducing the risk of thrombosis and increasing the flow of oxygen and nutrients to tissues and cells.

Reduce general content cholesterol in the blood (omega-3), primarily due to its most atherogenic (affecting atherosclerosis) fraction - low-density lipoproteins (LDL) and increase the content of lipoproteins high density(HDL). They also have cardioprotective and antiarrhythmic effect. All these factors reduce the risk of atherosclerosis, coronary disease heart, myocardial infarction, stroke.

IN Lately There have been studies showing that omega-3 fatty acids can block tumor growth, have implications for normal height children, regulate the metabolism of serotonin - the “hormone Have a good mood", reducing the risk of depression.

Omega-3 fatty acids are found in fatty rocks sea ​​fish, such as salmon, tuna, anchovies and sardines, in seafood, as well as in vegetable oils such as flaxseed, soybean and canola, and walnuts.

Omega-6 fatty acids are synthesized in most plants that grow on land, so their main source is vegetable oils - from wheat ovary, flax seed, soybeans, peanuts, camelina oil, mustard oil, sunflower oil, as well as walnuts, almonds, sunflower seeds.

Currently, the following is considered the optimal nutritional ratio of PUFAs of various families: ω-6: ω-3 = 6-10: 1.

In addition, there are many food additives containing omega-3 fatty acids (based on fish oil or seaweed) and omega-6 fatty acids (based on borage oil or evening primrose oil).

Many experts believe that approximately 80% of our country's population does not consume enough essential fatty acids. The daily need for them is 10-20% of the total calories received. Deficiencies in these nutrients pose a serious health threat.

Phospholipids and sterols. Phospholipids consist of glycerol esterified with polyunsaturated fatty acids and phosphoric acid, which is combined with a nitrogenous base.

Their main purpose is that they, along with cholesterol, are the structural basis of cell membranes and organelle membranes. Phospholipids are important components of surfactant in the alveoli of the lungs, lipoproteins in blood plasma and bile. They take part in the functioning of the nervous system - without them the function of excitability and transmission of nerve impulses is impossible. Phospholipids in platelet membranes are essential in the blood clotting process to stop bleeding.

Phospholipids are completely broken down in intestinal cells, so their endogenous synthesis in the liver and kidneys is crucial for the body.

The most important phospholipid is lecithin, consisting of glycerol, fatty acids, phosphoric acid and choline. It is a cholesterol antagonist and plays important role in protecting the body from atherosclerosis. Lecithin accelerates oxidative processes, growth and development processes, increases the body's resistance to the effects of toxic substances(poisons), stimulates bile secretion, takes part in water metabolism, promotes the absorption of fat in the intestines, stimulates the formation of red blood cells and hemoglobin, has great importance in regulating fat metabolism in the liver, preventing its fatty infiltration.

Lecithin is rich in egg yolk, liver, milk fat and mainly products of plant origin - soybeans, beans, buckwheat, green pea, unrefined vegetable oils.

Lecithin is synthesized in the body itself, but if it is absent from food for a long time, a deficiency may occur. Daily requirement human lecithin is 0.5 g.

The main animal sterol is cholesterol. In conditions balanced nutrition its endogenous synthesis (biosynthesis) from EFA in the liver is at least 80%, the rest of cholesterol comes from food.

Functions of cholesterol that play important physiological roles in the body:

Is provitamin D3;

Serves as a starting product for the synthesis of sex hormones and adrenal hormones;

Participates in the formation of bile acids.

The optimal level of its intake in the diet is considered to be 0.3 g/day. Products of animal origin are rich in cholesterol: fish caviar, brains, internal organs of animals (liver, kidneys, etc.); animal fats (lamb, beef, pork, etc.); fatty varieties meat (pork, goose, duck, etc.), fish (sturgeon, stellate sturgeon, etc.); chicken yolk; butter, cheese, sour cream, cream. There is almost no cholesterol in foods of plant origin.

In blood and bile cholesterol is found in the form colloidal solution due to binding to phosphatides, PUFAs and proteins. When the metabolism of these substances is disturbed or their deficiency occurs, cholesterol falls out in the form of small crystals that settle on the walls of blood vessels and bile ducts, which contributes to the appearance of atherosclerotic plaques and gallstones.

Fat should account for an average of 30% energy value daily diet, and the share of animal fats should account for 70%, the share of vegetable fats - 30%

Consequences of excess intake of fats from food. In the gastrointestinal tract healthy person at a normal level of fat intake, about 95% of their total amount is absorbed. In food, fats are presented in the form of actual fatty products (oil, lard, etc.) and so-called hidden fats, which are included in many products. It is foods containing hidden fat that are the main suppliers of dietary fats to the human body.

High dietary intake of EFAs and cholesterol itself is accompanied by an increase in the total concentration of triglycerides and fatty acids in the blood and an increase in the amount of lipoproteins circulating in the blood. All this leads to hyperlipidemia, and subsequently to the development of dyslipoproteinemia - a basic violation of nutritional status that underlies the development of atherosclerosis, diabetes mellitus and overweight and obesity.

Most lipid compounds in the human body can, if necessary, be synthesized in metabolic processes from carbohydrates. The exception is the essential polyunsaturated fatty acids linoleic and linolenic, which are included in the ω-6 and ω-3 families, respectively.

Fats are absolutely necessary in healthy eating, they play a huge role in ensuring the life of our body . They are involved in the absorption of vitamins and the production of cell membranes, hormones and prostaglandins. They improve the taste of food and also control satiety levels with two different ways. When fats enter the stomach, they stimulate the secretion of the hormone esterogastrone, which prevents food from passing through the gastrointestinal tract. Thus, fatty foods stay in the stomach longer, slowing down digestion. At the same time, fatty foods stimulate the secretion of the hormone CCK, which lets the brain know that a person's stomach is full, thereby controlling hunger levels. Without fat in the diet, the production of estrogen, which is necessary for bone repair, decreases, i.e. for the process that goes into normal body continuously. This causes premature osteoporosis, a disease in which bones become thinner and more fragile. Therefore, you should not reduce fat content below the physiological norm.

Fats are the only source of fat-soluble vitamins, which play a very important role in the body's vital processes. Therefore, a lack of fat in food can cause serious metabolic disorders. Depending on the total calorie content of food, it is recommended for an adult to consume from 75 to 110 g of fat per day, and at least one third should be animal fat, mainly milk fat.

In addition to fats of animal origin, the diet must also include vegetable fats, since they contain very valuable substances for the body, the so-called unsaturated fatty acids (oleic, linoleic, arachidonic, etc.).

Due to the fact that fats have a higher calorie content than proteins and carbohydrates, the presence of fat makes it possible to regulate the amount of food. When replacing fats with carbohydrates, the volume of food increases, because to maintain the calorie content of food, you have to take more than twice as much carbohydrates as fats. In northern conditions, fats play a particularly important role - they make it possible to increase the calorie content of food without significantly increasing its volume.

All fats and oils - butter, lard, sunflower and other vegetable oils - are almost 100% fat. Fats and oils are almost pure food substances and at the same time food products. Other fats are found in many animal and plant foods and are invisible to the eye.

In developed countries of Europe and America, fats in the diet account for 30-45% of energy, in developing countries of Asia and Africa - 15-25%. The recommended energy intake from fat is 15-30%. To meet the need for essential fatty acids, 2 tablespoons of vegetable oil is sufficient.

Important information about fats

• 1. Fat consumption standards are individual. It is recommended to eat 1 - 1.3 grams of fat per 1 kilogram of weight per day. For example, if your body weight is 60 kilograms, then you need to eat 60 - 70 grams of fat per day. 2. Try to avoid foods containing a lot of saturated fat: fatty meat, sausages, fatty dairy products.3. Reduce the amount of vegetable oils containing Omega-6: sunflower, corn, peanut.4. Add oils containing Omega-6 to your diet: canola, flaxseed, hemp, soybean and mustard.5. Try to eat less fried food. For frying, use only refined oils. Give preference to olive oil.6. Avoid trans fatty acids.7. Be careful when buying sweets for children. Almost all confectionery products (chocolate bars, waffles, cookies, ice cream, etc.) contain margarine (hydrogenated vegetable oil), which negatively affects children's health.
• 3. The role of carbohydrates in nutrition

Despite the fact that fats provide the most calories during oxidation, the main source of energy is carbohydrates, the combustion of which requires less oxygen than the combustion of fats and, especially, proteins. In addition, when carbohydrates are oxidized, energy is released 4 times faster than when fat is burned.

The daily requirement for carbohydrates is 300-400 g.

Food includes simple and complex, digestible and indigestible carbohydrates. Main simple carbohydrates are glucose, galactose and fructose (monosaccharides), sucrose, lactose and maltose (disaccharides). Complex carbohydrates (polysaccharides) include starch, glycogen, fiber, pectin, and hemicellulose.

Carbohydrates are necessary for normal exchange proteins and fats in the human body. In combination with proteins, they form some hormones and enzymes, secretions of the salivary and other mucus-forming glands, as well as other important compounds.

Of particular importance are fiber, pectins, and hemicellulose, which are only partially digested in the intestines and are an insignificant source of energy. However, these polysaccharides form the basis of dietary fiber and play an important role in nutrition. Carbohydrates are found mainly in foods of plant origin.

Glucose is the main supplier of energy for the brain. It is found in fruits and berries and is necessary for energy supply and the formation of glycogen in the liver.

Fructose almost does not require the hormone insulin for its absorption, which makes it possible to recommend its sources for diabetes mellitus, but in limited quantities. The main suppliers of sucrose are: sugar, confectionery, jam, ice cream, sweet drinks, as well as some vegetables and fruits: beets, carrots, apricots, peaches, sweet plums and others.

Lactose is found in dairy products. With congenital or acquired (most often as a result of intestinal diseases) deficiency of the lactose enzyme in the intestines, the breakdown of lactose into glucose and galactose is disrupted and intolerance to dairy products occurs.

Starch makes up 80% or more of all carbohydrates in the human diet. Its sources include flour, cereals, pasta, bread, legumes and potatoes.

Pectins stimulate digestion and promote the elimination of harmful substances. There are especially many of them in apples, plums, gooseberries, and cranberries.

Lack of carbohydrates leads to disruption of fat and protein metabolism, consumption of food proteins and tissue proteins. accumulate in the blood harmful products incomplete oxidation of fatty acids and some amino acids, the acid-base state of the body shifts to the acidic side. With a severe deficiency of carbohydrates, weakness, drowsiness, dizziness, headaches, hunger, nausea, sweating, and trembling in the hands occur. These phenomena quickly disappear after taking sugar. With long-term restriction of carbohydrates in the diet, their amount should still not be below 100 g.

Excess carbohydrates can lead to obesity. Systematic excessive consumption of sugar and other easily digestible carbohydrates contributes to the manifestation of latent diabetes mellitus due to overload and then depletion of pancreatic cells that produce insulin necessary for the absorption of glucose.

Fats are substances that primarily perform an energy function in the body, since when they are burned, 2 times more energy is released (1 g of fat produces 9.3 kcal, while 1 g of protein and the corresponding amount of carbohydrates only 4.3 kcal ).

Fats are involved in plastic functions, being a structural part of cells and their membrane systems. Lack Accurate fat intake can lead to:

Disturbance of the central nervous system due to disruption of the direction of nerve signal flows;

Weakening of immunological mechanisms;

Changes in the skin, where they play a protective role, protecting against hypothermia, increasing elasticity and preventing drying and cracking;

Violation of internal organs, in particular the kidneys, which protect from mechanical damage.

Fat improves the taste of food and increases its nutritional value. Only together with food fats does the body receive: fat-soluble vitamins, phosphatides (lecithin), polyunsaturated fatty acids, sterols, tocopherols, etc.

In the human body, fat is found in two forms: structural (protoplasmic) and reserve (in fat depots).

The amount of protoplasmic fat is maintained in organs and tissues at a constant level and does not change even during fasting.

The degree of accumulation of reserve fat depends on the nature of nutrition, the level of energy expenditure, age, gender, and the activity of the endocrine glands.

Heavy physical work, some diseases, and poor nutrition help reduce the amount of stored fat. And, conversely, excess nutrition, physical inactivity, decreased function of the gonads, thyroid gland lead to an increase in reserve fat.

FOOD FATS - from esters of glycerol and higher fatty acids.

The most important component that determines the properties of fats are fatty acids. They are divided into saturated (marginal) and unsaturated (unsaturated). The most important in terms of their distribution in food products and their properties are saturated acids (butyric, stearic, palmitic), which are found in animal fat and make up up to 50% of the fatty acids of lamb and beef fat, causing a high melting point and poorer digestibility.

Of the unsaturated fatty acids, the most important are linoleic, linolenic and arachidonic acids, collectively known as vitamin-like factor F. The first two are common in liquid fats (oils) and in marine fish oil. Vegetable oils (sunflower, corn, olive, flaxseed) contain up to 80-90% of the total fatty acids.

Of great importance is arachidonic PUFA, which is found in small quantities in some animal fats; it is absent in vegetable oils. So, pork fat contains 500 mg% arachidonic acid 5 times more than beef and lamb fat, and it contains 20% less saturated acids.

Thus, the nutritional and biological properties of pork fat are higher than those of beef and lamb.

An indicator of the biological value of fats is also the presence of vitamins A, D, E. Therefore, butter containing these vitamins, despite the low level of PUFAs, is a product of high biological value.

II. Biological role of phosphatides. ( lecithin, cephalin, sphingomyelin.)

In combination with proteins, they are part of the nervous tissue, liver, heart muscle, and gonads.

They participate in the construction of cell membranes and determine the degree of their permeability to fat-soluble substances.

They participate in the active transport of complex substances and individual ions into and out of cells.

Phospholipids are involved in the process of blood clotting.

Promotes better utilization of protein and fat in tissues.

Prevent fatty infiltration of the liver.

They play a role in the prevention of atherosclerosis - they prevent the accumulation of olesterol in the walls of blood vessels, promote its breakdown and removal from the body.

Due to these properties, phosphatides are classified as lipotropic factors.

(65) is contained in squirrels treski, eggs, meat, i.e. In proteins of animal products.

Nature has the highest content of sulfur-containing amino acids (methionine + cystine) in grainssunflower.

2. Lysine- closely related to bloodcreation. With a deficiency, the number of red blood cells and the number of HB decreases.

With its deficiency, there is a violation of bone calcification and muscle wasting. Lysine is essential for the growth of young organisms. Main source - milknary protein. Cottage cheese contains 1.5% of it. Availablealso in animal meat.

3. Tryptophan is an amino acid necessary for the synthesis in the body of nicotinic acid, hemoglobin, the formation of whey proteins, and growth factor. The younger the age, the higher the need for tryptophan (1.0).

But tryptophan is quite difficult to collect in sufficient quantities, because 100 g of meat and eggs contain only 0.2 g.

In milk, tryptophan is found in albumin, which, when heated above 70 ° C, is denatured and precipitates on the wall of the dish, therefore, tryptophan is also lost. It is best to consume raw milk from a healthy cow.

Products - sources of complete protein (%)

Meat - 16-22 fish - 14-20

poultry - 6-24 eggs - 12.5

egg powder - 52 milk - 3.4

skinny cottage cheese - 17.5 fatty cottage cheese - 13

different cheeses - 18-25

Proteins from plant products are less complete in amino acid composition.

But the inferiority of the amino acid composition of plant proteins is compensated by eating mixed foods and especially through the rational selection of various products of plant and animal origin.

In addition, among plant foods there are legumes containing large amounts of complete proteins:

Peas - 19.8%

Beans - 19.6%

Lentils - 20.4%

pea flour - 22%

5) low-fat soy flour - 41.4%

The proteins of these products have sufficient quantities of especially valuable amino acids, such as tryptophan, lysine, methionine, and soy contains even more of these amino acids than meat, and it contains as much methionine as cottage cheese.

(66) The need for phosphatides is 5-10 g/dayki.

Among plant products, unrefined oils are characterized by significant content.

Abroad, soy lecithin is used as a source of phosphatides.

Our country produces phosphatide concentrates - sunflower and soybean, used for refined vegetable oils and margarine. Obstacles to the use of these concentrates are their unsatisfactory taste properties, rapid oxidation and rancidity.