What is the best fat? Choose a healthy source of fat.

Today, the role of fats in living organisms is abundantly overgrown with misconceptions. A clear explanation of the purpose of this, undoubtedly, an important component of food, remains a mystery to many. The article will describe in an accessible language the properties of these organic compounds, their role in the construction of our body, and the functions of body fat. Let's also talk about a common myth about the energy value of fats, their true purpose and eating fatty foods.

Fats - a source of energy?

There is such a very common misconception that fats are not only the best source of energy, but also a form of its supply. A long time ago, German scientists using a calorimeter calculated that when oxidized (burned), a fat molecule releases almost 2 times more energy than proteins and carbohydrates. Hence the myth was born that fats are very valuable for the body in terms of their energy content. And the logic was attached that a layer of fat is the result of the actions of a thrifty organism, which is preparing for unforeseen hunger strikes. Today these postulates are one of the main ones in the system rational nutrition, which is emphasized by doctors and nutritionists.

The theory is beautiful. But even at the slightest attempt to put it into practice, “bummers” occur. If fat were such a great source, then fat people would be the most "prepared for stress" in terms of nature? They are so “charged with energy” that they would run for hours without fatigue, well, except that they would lose weight a little towards the finish line, losing calorie reserves. In reality, as you know, everything is not so rosy. And do we feel briskly after eating fatty foods? You can pay attention to the sensations, or try to feed pet mostly fat and you will not see "miracles of mobility", but laziness and slowness. Is it always more fat man more comfortable with hunger? Of course not! And the more his “reserves”, the more often it is harder for him without food.

It turns out that the theory of the nutritional value of fats fails miserably if applied to practice.

Think about it, because in nature there are many substances that, when burned, will release much more energy than from fat: the same gasoline, gunpowder, methane. But no one would think to eat them, - we are simply not adapted to receive energy from them. It seems obvious! Fats, including - they are not a source of energy for us. We are simply not adapted to them! Then why are they in our diet, and is it worth using them at all?

Why are fats needed?

Only as a building material for our cells.

The use of fats as an energy source is unprofitable. In practice, when splitting fats, only glycerin is suitable for replenishing energy needs. The remaining fatty acids for the body are the first on the list for output to the outside, i.e. useless and even harmful ballast! For this there is

In nature, the fat layer serves primarily as a heat insulator, and therefore prevails in marine mammals and in short-haired inhabitants of a variable climate. It is also used not only to deposit nutrients for a "rainy day", but as buffer. Those. "Utility" is not once put into the "bank", but goes ongoing process exchange of vitamins, hormones, toxins, depending on the situation, between deposits and internal organs. Also, adipose tissues allow you to “preserve” tasks for later, for example, by putting aside food leftovers that this moment difficult to remove from the body. Kind of a waste dump.

It should be understood that stored animal or vegetable fats are unable to perform their direct functions - to be a heat insulator or a quality nutrient buffer. These are "canned problems"! This is what the body is trying to remove, but it simply does not have enough “strength” due to the endless stream of similar food. Animal fats practically do not change and “lie down” unchanged, while vegetable fats are deposited in liquid form. This is what most of us live with for years.

But we, humans, need fats of our own production, which will perform the function assigned to them! Not from pigs, not from fish or poultry, not even from bananas and nuts, and even more so from creams and oils. Only fats synthesized by our body will work as they should!

The use of fat is ideal only as part of the cells of raw plant foods in terms of the amount needed to build your own tissues. Other vegetable oils, even if first cold pressed, are simply unable to perform these tasks. These are "dead" elements with a destroyed structure.

What happens when there is too much fat in the diet?

All Live nature uses carbohydrates as its main source of energy. Protein and fats- only building material, "bricks" for the cells of our body. perestroika internal processes for the use of building materials as an energy source is possible, and this is achieved, first of all, by changing a number of functions.

Predominantly protein nutrition will necessarily lead to unwanted body odors, skin problems, diseases and violations of many internal processes. Putrefactive processes will begin to predominate in the gastrointestinal tract. Fats “break” the body much faster. The body tries to get rid of fatty acids in the first place in all possible ways. And the fats that have passed heat treatment, especially oils and fat - the strongest poisons. With them frequent use guaranteed skin problems, a terrible smell of sweat, the manifestation of many abnormalities, such as dandruff, fungi, psoriasis, tonsillitis. Also, their systematic use in food pretty quickly destroys the metabolism in the body.

If your diet is rich in oils and fats, then almost all incoming carbohydrates are converted from an energy source into "fuel" for the utilization of fats. Restructuring to a similar scheme takes a rather long period, as well as back.

Part of the fats broken down by the body is undoubtedly energetically valuable. But only for serious physical activity they are able to "melt" into glycerol and fatty acids. The first goes to energy, the second goes to the blood. This gives a serious overheating of the whole organism. But this is how many of us warm up, and not due to quality native heat insulator material. Therefore, people with abundant body fat have serious problems s in hot weather. In the cold, as you know, the situation is no better.

Our body is very strong and a person is able to eat proteins and fats, but carbohydrates are his native food.

Increasing the "right fat"

The first step is to get rid of old deposits, with all its contents. I repeat that with an abundance fat in the diet, the body redirects the energy of carbohydrates for their utilization. You just need to increase their influx and remove fats from the diet. contain complete, structured fats, in the composition of cells and their amounts more than enough for construction work. They are also rich in live carbohydrates. The next component will be physical activity, preferably aerobic, which will make it better to burn fat and use its parts to replenish energy needs. Remember the saying “fats burn in the fire of carbohydrates”?

Only when everything unnecessary is reset and carbohydrate metabolism is released (which will not happen soon), the body will be able to build high-quality, “own” adipose tissue.

If a course is taken for specific nutrition, then in the first months of perestroika, fat burning occurs at a Stakhanovite pace. Not a trace remains of him, and the new one is still a long period does not increase, which is also not the norm. This is due to the fact that the body simply has nothing to put into it. No toxins or excess nutrients. But as soon as there is a restructuring on a raw diet and there is no shortage of substances, the body will begin to intensively “storage” part of the excess, creating a high-quality fat layer. Which, despite its moderate volumes, will perfectly cope with its tasks: to warm and nourish when necessary. Its quality will be incomparable with previous "versions". It can never be too much.

I would also like to note that often at the stage of restructuring, people manage to gain weight due to the abundant consumption of concentrated protein and fatty foods: nuts, legumes, avocados, etc. As a result, the emerging layer is nothing more than a deposition of unutilized vegetable fats. And it is worth removing these products from the diet, as the body pretty quickly eliminates all this. Remember that this is an unhealthy body weight, although given the possible excessive weight loss, sometimes desirable. For the environment.

Total comments: 27

• From your story, I get the impression that you are seriously limiting yourself. It is difficult to judge such things from what is written and I could be wrong.
  But what if you try to take a “step to the left”: change something in your diet, get addicted to sports (how about it?). No need to self-torture yourself and understand literally what is written: drop everything and eat only beetroot with cabbage, chaining yourself to the battery from disruptions to fruit

  Can slowly shift your diet, based on feelings would be more reasonable? Maybe you should look for more "favorite" products, or include vegetable salads ... etc.

  Understand, it won’t be like “right now I’ll suffer for a month, and then you can eat everything in a row.” What works systematically works! Sport will only work if it is part of your life, like a vegetable diet, like giving up nuts, etc. Throwing only leads to nervous tension. Any drastic physiological changes provoke a restructuring of the psyche. Remember at least women's hormonal changes and associated irritability.

  Maybe take a closer look at other "tracks"? Take it not as a deviation from direct advice in the style of “eat this!”, But as an impetus to independent action. You are more than capable of them.

  • Yuri, hello!
    On the day of your answer, I wrote a long response comment, but it has not been preserved and is not

    went, and I decided that it means it’s not necessary, which means he should have reached you in

    that form. But now I decided to answer anyway.
    Yes, I understand that from my writings one can draw a conclusion about a very unstable

    state of mind, which is partly true, hehe ...))) But still I want to note that

    it was written in a hurry, at work, without editing and as concisely as possible. Here

    and it turned out so chaotically and almost desperately.))) Although, of course, given that more

    I have been doing this groping for the optimal diet for a year, this is normal,

    that I'm tired of this and I want some kind of stabilization.) And most importantly, I want to

    so that food occupies a smaller part of the brain.))
    And about the restrictions, I want to say that I decided to sit on vegetables temporarily before

    how to change your diet. It's like, for example, before switching to CE, they advise

    get ready, get ready. I also decided to prepare for a protein-free diet.

    nutrition, move from ineffective CME to nutrition, albeit mixed, with

    salads, but without concentrated protein. So the restrictions were temporary

    measure, and at the moment I see that they have been successful. Almost a month without nuts

    And I must say that the body likes it along the way. Only now there was a stupid

    the habit of eating at night. Rather, I start eating in the evening, as soon as I arrive, and then

    sometimes I can't stop. And I start eating at 8-9, and finish at 10-11, or even at

    12. And I feel overeated.)) This is despite the fact that there is no this zhor when

    you shove everything into yourself with tears in your eyes - I say this for sure, this is not it. Those.

    I can easily not eat. It's all in the head. At some point, I just taught myself

    come, plan a salad (how I missed salads, it turns out, on CME) and

    play a video on your computer. And the salad is followed by fruits, then

    more, more .. This does not happen every evening, but often. And go to bed because of it

    became late. And sleep more. It's still a work in progress. If I finish late, then

    still "young". In short, I understand that if you remove overeating and overeating on

    night, then the diet is correct. Yesterday I didn’t eat at night, went to bed early, and

    today I feel lightness and abundance of energy.))) In fact, you see, it’s not even

    asked you about the effect of certain products on the body, because you are in this

    the issue is much more savvy than I am. And may your opinion not be the truth in

    of the last resort, it would still be interesting to get acquainted with it within the framework of that

    information that you consider most relevant. Oh how. %R

    About sports. More precisely, I would say, physical education. She has long been firmly

    settled in my life, and without it I'm no longer a tenant. =) In the morning I definitely do

    at least a small charge, and if time permits, then a more complete one. Summer

    started running. I am slowly starting to go to yoga. So that's it with this

    okay. Physical education has become a natural need of the body. A contrast

    a shower in the morning is an almost daily procedure.
    Anyway, Yuri. One question worries me. Period. Do you think they are gone?

    because of the wrong approach to CE? Now something on the fruit they return? I understand,

    that you cannot know this, but it is still interesting from the point of view of physiology that

    happened. Where did the estrogen go? :)) After all, everything is in order with the rest of the analyzes. At

    MRI. Well, everything is in order and everything is here. (the truth was found a cyst of the corpus luteum, and the gynecologist

    said what could be corpus luteum if there is no ovulation. Like, it's something

    other. What do not you understand). And while the state reproductive system, So

    say, almost like in women of age during menopause .. Maybe someday

    will there be an article on this topic? o:-) Still, she excites many girls. Thank you for

    live response and participation!

For every dieter, the number one enemy is probably fat. And not only the one that was deposited on the tummy, but also the fat that comes with food. However, in fact, fats (not all) are needed by the body and are no less useful than proteins and carbohydrates.

Proper nutrition and fats

Proper nutrition involves the use of the amount of calories, proteins, fats and carbohydrates necessary for the body.

A sufficient amount of healthy fats "threatens":

• good functioning endocrine systems s, which means that the nails will be strong, the hair will be thick, and the skin will be beautiful and healthy;
• proper functioning of the reproductive system;
• improving metabolism.

Why can you lose weight with proper nutrition by eating both fats and carbohydrates, without eating only apples?

One of the main provisions proper nutrition is to increase the number of meals. It is best to eat 5-6 times a day: 3 main meals (breakfast, lunch, dinner) and 2-3 snacks in between. It is due to this that the body stops storing fat for a rainy day (which happens on the contrary during diets) and begins to actively digest incoming food.

Types of fats

All fats are divided into:

• saturated,
• unsaturated.

Saturated fats

Such fats are easily deposited in the fat layer, which is completely inappropriate for the body and figure. They are more harmful to health and beauty than not. saturated fat.

Foods containing saturated fats:

• animal fats (e.g. butter, lard, cheese),
• foods fried in saturated fats (such as lard)
• coconut and palm oils
• fatty pork,
• dairy.

However, this does not mean that saturated fats should be eliminated from the diet once and for all. Only an increased interest in such products can lead to diseases and problems with weight. But moderate consumption of saturated fats will only bring benefits.

For example, butter, although a source of saturated fat, is still healthy to consume. You can put a small piece of butter in the morning in porridge or make a couple of sandwiches with it.

Pork and dairy have also been shown to contain saturated fats, but that's okay. Just choose foods with less fat.

trans fats

trans fats obtained by converting unsaturated fats into saturated fats. Products from this category are very harmful and high in calories, so it is best to limit them to the maximum.

Products containing trans fats:

• confectionery,
• margarine, spread,
• fast food (hamburgers, chips, crackers, etc.).

Of course, everything is good in moderation, and a couple of hamburgers every six months will not hurt. But it's better not to get carried away.

unsaturated fats

unsaturated fats more beneficial to humans than saturated ones. For the normal functioning of the body, it is necessary and sufficient to consume 1 gram of fat per 1 kg of body weight.

Foods containing unsaturated fats:

• Fish and seafood,
• vegetable oils,
• avocado,
• nuts.

Sources of healthy fats

Fish and seafood

Both fish and seafood are a source of omega-3 unsaturated fatty acids necessary for humans. Omega 3 fatty acids needed for normal operation cardiovascular, nervous and endocrine systems, musculoskeletal system.

In addition, fish and seafood are high in protein and are considered low-calorie foods.

Vegetable oils

Almost all vegetable oils are a source of healthy omega-3 and omega-6 fats: linseed, sunflower, olive, corn, mustard, soybean, etc. Omega-6 unsaturated fatty acids help reduce blood cholesterol levels, strengthen immunity, increase brain activity, etc.

Avocado

Despite the fact that avocado is a fairly high-calorie fruit, it can and should be eaten. Avocado contains unsaturated fatty acids, which help the body to function normally and maintain the condition of the skin, hair, and nails.

In 100 gr. avocado contains:

• 2 gr. squirrel;
• 21 gr. fats;
• 7.3 gr. carbohydrates;
• 208 kcal.

It is best to consume avocados in the morning for breakfast.

nuts

The use can reduce the concentration of cholesterol in the blood, has a beneficial effect on the work of the heart in particular and the body as a whole. Nuts, like avocados, are high in calories. For example, in 100 gr. walnuts contains:

• 15, 1 gr. squirrel;
• 65.2 gr. fats;
• 7 gr. carbohydrates;
• 653 kcal.

Even for those who want to lose weight, it is very useful to eat nuts. Daily rate a weight-bearing person is about 10 nuts. If you're trying to lose weight and you're confused by the high calorie content of nuts, cut back to 5 nuts and get the fats you need from other foods (such as fish or oils).

By the way, the optimal ratio of omega-3 to omega-6 is approximately 1:4. An excess of omega-6 in relation to omega-3 increases the risk of certain diseases. Eating right, it is not enough to use only a spoonful of oil on an empty stomach as healthy fats, for example. Try to diversify your diet by eating fish, seafood, avocados, and nuts.

Outcome

As you can see, fats should not be afraid. At right approach fat is one of the main companions on the way to a healthy body and a beautiful body.

Be healthy and happy!

I think you are well aware that completely eliminating fat from the menu is a bad way to get a slim figure. But some people still can't resist low-calorie, low-fat foods. Then, especially for you, I will remind you once again: fats are essential for the body!

Fats, like other nutrients, must be ingested in enough, as they perform a number of specific functions, namely:

• Participate in the formation of body cells. This means that the skin will be elastic, the nerves and blood vessels will be strong, and the brain will be efficient.
• Important for maintaining immunity. Pay attention to whether you start to catch a cold more often when you are on a diet.
• Needed for normal digestion. The assimilation of many vitamins and microelements is impossible without fats.
• With a lack of fat in the diet, reproductive functions organism.

Of course, if you are on a diet, the temptation to cut down on fat is very strong. After all, you can eat a lot more other foods that way. However, according to the recommendations of nutritionists, the daily diet should consist of 20-30% fat. True, given the high calorie content of fats (9 kcal / g), this is not so much: about 25 grams for every thousand kilocalories (a little more than a tablespoon of vegetable oil or a couple of slices of bacon). Therefore, this small amount of calories is best obtained from healthy sources of fat.

Let's remember the lessons of chemistry

Fats are organic compounds that break down to form fatty acids. The part of the fatty acid molecule that interests us is the carbon chain, the structure of which differs in acids. Between carbon atoms there can be single bonds (then fats are saturated) or double / triple (monounsaturated or polyunsaturated - for one or more double / triple bonds in the carbon chain).

However, all of the above does not mean that there is some kind of oil or fat in which we will find fatty acids of only one structure. Natural products are mixtures of chemical compounds of very different structures. Sources of saturated fatty acids - products of animal origin: dairy, pork, beef, mutton fat. Sources of unsaturated fatty acids are usually oils plant origin. But there are exceptions:

• fish and chicken fat, liquid at room temperature, is a source of unsaturated fatty acids,
• butter, palm, coconut and cocoa butter, solid at room temperature, are sources of saturated fatty acids.

To classify a product as a source of saturated or unsaturated acids, it is worth focusing not on its generally accepted name (oil or fat), but on whether it is liquid at room temperature or not.

What fatty acids do we need

To date, most nutritionists are inclined to believe that it is more beneficial for our body. unsaturated fats. They help to normalize the level of cholesterol, insulin and blood sugar.

For advertising purposes, special emphasis is placed on polyunsaturated acids omega-3 and omega-6. The main feature of these acids is that the human body cannot produce them on its own, so they must be supplied in sufficient quantities with food. Moreover, in a certain ratio, namely 1:4 (ω-3:ω-6).

Useful polyunsaturated acids omega-3 and omega-6 should be supplied to the body in a ratio of approximately 1:4.

However, monounsaturated fats are also good for the body, especially for the heart.

As for saturated fats, they take part in such biologically important processes as building cell membranes, assimilation of vitamins and microelements, synthesis of hormones (ladies, this is especially important for you!). True, they require less than unsaturated ones.

Most health organizations around the world agree that saturated fat should make up no more than 10% of the daily diet. This means that the average male who spends most life in an armchair (office, car, warm in front of the TV), about 30 grams of butter are put per day. And if you take into account those saturated fats that come with other products (meat, fast food, dairy products), you can safely divide this amount in two.

A pack of butter is usually 180 grams. We divide it into 12 parts - we get the "allowed" 15 grams. Women can safely divide a pack into 18 parts.

However, it doesn't make sense to cut out saturated fat altogether. They are the best option for frying food, since the double bonds of unsaturated fats during heat treatment are actively oxidized directly into carcinogens.

You can also try using coconut and palm oils for this purpose, which are closest to butter in chemical composition. However, it should be remembered that the price of such oils must be quite high in order to guarantee their high quality.

For cooking products, it is better to use saturated fats (butter, lard, coconut and high-quality palm oil), since the oxidation of unsaturated fats leads to the formation of carcinogens.

What should definitely be avoided are trans fats (margarine, spreads, cheap confectionery, mayonnaise, fast food). Trans fats are the "bad" isomers of healthy unsaturated fats. They are formed during the hydrogenation of vegetable oils. Usually, during this process, liquid vegetable oils become thick and opaque. The harm of trans fats has already been confirmed, and health organizations around the world advise to reduce their amount in food as much as possible.

So, let's make an intermediate conclusion:

1. Fats are essential for the human body. But their number should not be too high.
2. Animal fats (lard, fatty meat, butter) are good for cooking food.
3. Trans fats should be eliminated from the diet as much as possible.
4. Most of the incoming fats should be a source of unsaturated fatty acids.

Choosing sources of unsaturated fats

Healthy fats, as well as almost all vitamins, are found in fish. Most of them in the following types: sea ​​bass, chum salmon, mackerel, carp, salmon. Naturally, fresh fish should be preferred over canned and smoked fish.

But the main source of unsaturated fatty acids are vegetable oils. Their choice is wide: sunflower, olive, linseed, camelina, pumpkin, sesame, mustard, corn, rapeseed, grape seeds, wheat germ, walnuts ... The list is endless, because if you want to squeeze oil, you can squeeze a lot of what products.

Almost every vegetable oil is a source of omega-3 and omega-6 essential polyunsaturated fatty acids. Let me remind you once again that the proportion of omega-3 in the incoming food should not be too high.

There is absolutely no omega-3 in sunflower and coconut oil, as well as in more exotic varieties - saffron, macadamia oil.

There is a lot of omega-6 in grape seed oil, as well as in cottonseed and sesame. The closest ratio of ω-3:ω-6 to the optimal 1:4 in linseed (1:0.2), rapeseed (1:1.8), mustard (1:2.6) and walnut oils (1:0.2) 5).

The record holders for the content of monounsaturated fats are olive and canola oils.

Sunflower and rapeseed oils contain the most vitamin E. Olive, sesame and linseed contain less.

AT mustard oil also contains a significant amount of vitamin A and beta-carotene.

Summarize

1. Oils and fats are very high in calories, so you need to add them to food in in large numbers.
2. There is no point in avoiding fats: without them, you will not be able to absorb vitamins, and the body will not be able to function normally. Salad without oil will only be a source of fiber, and most useful substances so they won't get it.
3. Focus on oils / fats not by their name, but by their state of aggregation at room temperature: liquid ones contain more unsaturated fatty acids, and solid ones contain saturated ones.
4. The best option would be a more or less balanced diet, in which vegetable oils will be the main sources of fat. Add them to prepared meals. But frying with vegetable oils should not be.
5. For frying, the most ordinary butter is better.
6. Try to exclude as much as possible from the menu products containing trans fats (fast food, low-quality confectionery, semi-finished products and prepared food unknown composition). Avoid spreads, in other words - butter with the addition of vegetable hydrogenated.
7. Try to listen to body signals: try different healthy oils and adjust to your taste.

2.3. Fats and their importance in nutrition

Fats (lipids) - These are complex organic compounds consisting of triglycerides and lipoid substances (phospholipids, sterols). The composition of triglycerides includes glycerol and fatty acids 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. Dietary fats can be animal or vegetable in nature. According to the chemical structure, vegetable oils differ from animal fat in fatty acid composition. The high content of unsaturated fatty acids in vegetable oils gives them a liquid state of aggregation and defines them nutritional value. Vegetable fats (oils) are normal conditions in a liquid aggregate state with the exception of palm oil.

Fats play significant role in the life of an organism. They are the second most important source of total energy from food after carbohydrates. At the same time, having the highest caloric coefficient among energy-bearing nutrients (1 g of fat gives the body 9 kcal), fats, even in a small amount, can give a product containing them a high energy value. This circumstance is not only positive value, but it is also a prerequisite for the formation of a rapid and relatively unrelated to large volumes of food intake of excess fat and, accordingly, energy.

The physiological role of fats, however, is not limited to their energy function. Dietary fats are direct sources or precursors of formation in the body

In the gastrointestinal tract of a healthy person, at a normal level of fat intake, about 95% of them are absorbed. total.

In the composition of food, fats are presented in the form of proper fatty products (butter, lard, etc.) and the so-called hidden fats that are part of many products (Table 2.6).

Table 2.6

Major Sources of Dietary Fats

It is products containing hidden fat that are the main suppliers of dietary fats to the human body.

Fatty acids that make up dietary fats are divided into three large groups: saturated, monounsaturated and polyunsaturated (Table 2.7).

Table 2.7Essential fatty acids of food and their physiological significance

Saturated fatty acids. Saturated fatty acids (SFAs), most represented in food, are divided into short-chain (4 ... 10 carbon atoms - butyric, caproic, caprylic, capric), medium-chain (12 ... 16 carbon atoms - lauric, myristic , palmitic) and long-chain (18 carbon atoms or more - stearic, arachidine).

fatty acids with short length carbon chains practically do not bind to albumins in the blood, are not deposited in tissues and are not included in lipoproteins - they are able to quickly oxidize with the formation of energy and ketone bodies. In addition, they perform a number of biological functions, for example, butyric acid serves as a modulator of genetic regulation, immune response and inflammation at the level of the intestinal mucosa, and also provides cell differentiation and apoptosis. Capric acid is the precursor of monocaprin, a compound with antiviral activity. Excess intake

Short-chain fatty acids can lead to the development of metabolic acidosis.

Fatty acids with medium and long carbon chains, on the contrary, are included in the composition of lipoproteins, circulate in the blood, are stored in fat depots and used to synthesize other lipoid compounds in the body, such as cholesterol. In addition, lauric acid has been shown to be able to inactivate a number of microorganisms, in particular Helicobacter pylori, as well as fungi and viruses, by breaking the lipid layer of their biomembranes.

Lauric and myristic fatty acids increase serum cholesterol levels the most and are therefore associated with the highest risk of atherosclerosis.

Palmitic acid also leads to increased lipoprotein synthesis. It is the main fatty acid that binds calcium (in the composition of fatty dairy products) into an indigestible complex, saponifying it.

Stearic acid, as well as short-chain fatty acids, practically does not affect the level of cholesterol in the blood, moreover, it is able to reduce the digestibility of cholesterol in the intestine by reducing its solubility.

unsaturated fatty acids. Unsaturated fatty acids are subdivided according to the degree of unsaturation into monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA).

Monounsaturated fatty acids have one double bond. Their main representative in the diet is oleic acid (18:1 p-9 - double bond at the 9th carbon atom). Its main food sources are olive and peanut oil, pork fat. MUFAs also include erucic acid (22:1 and -9), which is "/ 3 of the composition of fatty acids in rapeseed oil, and palmitoleic acid (18:1 "-9), present in fish oil.

PUFAs include fatty acids that have several double bonds: linoleic (18:2 and-6), linolenic (18:3 p-3), arachidonic (20:4 p-6), eicosapentaenoic (20:5 l-3) , docosa-hexaenoic (22:6 p-U). In nutrition, their main sources are vegetable oils, fish oil, nuts, seeds, legumes (Table 2.8). Sunflower, soybean, corn and cottonseed oils are the main dietary sources of linoleic acid. Rapeseed, soybean, mustard, sesame oil contains significant amounts of linoleic and linolenic acids, and their ratio is different - from 2:1 in rapeseed to 5:1 in soybean.

In the human body, PUFAs perform biologically important functions related to the organization and functioning of

Polyunsaturated fatty acids are composed of two main families: linoleic acid derivatives, related to (o-6 fatty acids, and derivatives of linolenic acid - to co-3 fatty acids. It is the ratio of these families, subject to the overall balance of fat intake, that becomes dominant from the standpoint of optimizing lipid metabolism in the body due to fatty acid modification]

food composition.

Linolenic acid in the human body is converted into long-chain i-3 PUFAs - eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Eicosapentaenoic acid is determined along with arachidonic acid in the structure of biomembranes in an amount proportional to its content in food. With a high level of dietary intake of linoleic acid relative to linolenic (or EPA), the total amount of arachidonic acid included in biomembranes increases, which changes the functional properties.

As a result of the use of EPA by the body for the synthesis of biologically active compounds, eicosanoids are formed, the physiological effects of which (for example, a decrease in the rate of thrombus formation) can be directly opposite! eicosanoids synthesized from arachidonic acid. It has also been shown that, in response to inflammation, EPA is transformed into eicosanoids, providing a finer regulation of phases of inflammation and vascular tone compared to eicosanoids - derivatives of arachidonic acid.

Docosahexaenoic acid is found in high concentrations in the membranes of retinal cells, which are maintained at this level regardless of dietary intake of co-3 PUFAs. It plays an important role in the regeneration of the visual pigment rhodopsin. High concentrations of DHA are also found in the brain and nervous system. This acid is used by neurons to modify the physical characteristics of their own biomembranes (such as fluidity) depending on functional needs.

Recent advances in nutritional genomics confirm the involvement of co-3 PUFAs in the regulation of r

new, involved in the metabolism of fats and inflammation, due to the activation of transcription factors.

In recent years, attempts have been made to determine adequate levels of dietary intake of u-3 PUFAs. In particular, it has been shown that for an adult healthy person the use of 1.1 ... 1.6 g / day of linolenic acid in food completely covers the physiological needs of this family of fatty acids.

The main food sources of PUFAs of the u-3 family are linseed oil, walnuts (Table 2.9) and marine fish oil (Table 2.10).

Currently, the optimal ratio in the diet of PUFAs of various families is the following: u-6:co-3 = = 6 ... 10:1.

Table 2.9Major Dietary Sources of Linolenic Acid

Table 2.10The main food sources of PUFAs of the u-3 family

Phospholipids and sterols. The composition of dietary lipids includes such significant groups of substances as phospholipids and sterols. Phospholipids include lecithin (phosphatidylcholine), cephalin and sphingomyelin. Phospholipids are composed of glycerol esterified with polyunsaturated fatty acids and phosphoric acid, which is combined with a nitrogenous base. Dietary phospholipids promote the absorption of dietary triglycerides through micelle formation. They are completely broken down in the intestinal cells, so their endogenous synthesis in the liver and kidneys is of decisive importance for the body. Endogenous synthesis of lecithin, in particular, is limited by intake with PUFA diet and choline.

Lecithin has great importance in regulation fat metabolism in the liver - it refers to lipotropic nutritional factors that prevent fatty infiltration of the liver by activating the transport of neutral fats from hepatocytes. Food products containing the maximum amount of precursors for the synthesis of lecithin and itself include unrefined vegetable oils, eggs, sea fish, liver, butter, poultry, as well as phosphatide concentrates obtained as secondary raw materials during oil refining and used to enrich food products.

Sterols have a complex organic structure: they are hydroaromatic neutral alcohols. Animal fats contain cholesterol, and vegetable fats contain phytosterol. P-sitosterol has the highest biological activity among phytosterols. It is able to have a hypocholesterolemic effect, reducing the absorption of cholesterol as a result of the formation of indigestible complexes with the latter in the intestine. The participation of sitosterols in the organization of biomembranes has also been shown. Vegetable oils contain the following amount of p-sitosterol per 100 g of product:

The main animal sterol is cholesterol. Under conditions of a balanced diet, its endogenous synthesis (biosynthesis) from SFA in the liver is at least 80%, the rest of cholesterol comes from food. The optimal level of its intake With the diet is considered to be 0.3 g / day. Vitamins play an important role in cholesterol metabolism: ascorbic acid, B 6 , B, 2, folic acid, bioflavonoids. Cholesterol is key

importance in the organization and normal functioning of biomembranes, the synthesis of steroid hormones, calciferols, bile acids.

Consequences of excess intake of fats from food. A high dietary intake of SFAs and cholesterol itself is accompanied by an increase in the total concentration of triglycerides and fatty acids in the blood, an increase in the amount of lipoproteins circulating in the blood.

All this leads to hyperlipidemia, and further to the development of dyslipoproteinemia - a basic violation of the nutritional status underlying the development of atherosclerosis, diabetes mellitus and overweight and obesity. Dyslipoproteinemia is a violation of the ratio of various fractions of lipoproteins and triglycerides circulating in the blood, leading in various ratios to an increase in both the absolute and relative amounts of low and very low density lipoproteins (LDL and VLDL) and triglycerides while reducing the amount of HDL. The latter are components that reduce the atherogenicity of cholesterol.

From a biochemical standpoint, it is very important that it is the excessive intake of lauric, myristic and palmitic fatty acids with food that leads to the development of hypercholesterolemia and an increase in the concentration of the most atherogenic LDL in the blood. Stearic acid is not involved in the construction of LDL and does not have a hypercholesterolemic effect.

Simultaneously with the growth of LDL, a decrease in the concentration of HDL was noted with excessive consumption of trans-fatty acids with food. They are practically absent in natural fats, with the exception of a small content in the meat and milk of cows and sheep - in these animals, natural fatty acids are partially isomerized in the stomach. The main mass of trans-isomers is formed during the hydrogenation of PUFAs - the breaking of double bonds by hydrogen atoms in the production of margarine or the so-called soft oils (consisting of a combination of vegetable and animal fats). Long-chain fatty acids in food that enter the body in the form of trans isomers, for example trance-lS: one; cannot be included in the biosynthesis of biologically active cellular regulators (prostaglandins and leukotrienes), but are used only as an energy substrate.

With the intake of fat in an excess amount compared to the body's need, gluconeogenesis is also stimulated. The latter circumstance leads to a decrease in the degree of utilization of "carbohydrate" glucose from the blood, an increase in the load on the insular apparatus and manifests itself in a healthy person in an increase in the concentration of glycosylated hemoglobin ai c .

From a hygienic point of view, given that a person ms eats individual fatty acids, hyperlipidemia and dyslipoproteinemia, as well as metabolic hyperglycemia, should be considered as the result of an excessive intake of the entire volume of fatty foods and products containing hidden fat with food, regardless of their nature and fatty acids. acid composition.

In nature, there is no "ideal" source of fat in terms of optimal nutrition. The fatty acid composition of all used vegetable oils, along with a significant content of MUFAs and PUFAs, also includes significant amounts of medium-chain SFAs (10 ... 15% or more).

Marine fish is currently the only source of fat, an adequate increase in the consumption of which in place of animal fat and vegetable oil can be considered as an evolutionarily justified step. In this case, however, one should take into account the real possibility of intensifying the prooxidant load on the body, associated with the action of two factors:

the presence of a relatively large amount of PUFAs with a high degree of unsaturation (five and six double bonds), which therefore have a high ability to oxidize;

the absence of the main antioxidant, vitamin E, in fish fat.

An important issue is the safety of fish raw materials in terms of control over residual amounts of toxic elements, polychlorinated biphenyls and other contaminants, as well as natural toxins (this is especially true when non-traditional species of marine fish and other seafood are likely to be used).

Another way to optimize the fatty acid composition of food products is related to the possibilities of selection and genetic engineering within the framework of modern biotechnology. So, as a result of conventional breeding work, high-oleic sunflower oil and low-erucic rapeseed oil have already been obtained. Currently, scientific and practical developments are underway to create oilseeds and grain crops (primarily soybeans, rapeseed and corn) based on genetic modification with a given composition of fatty acids.

Given the possible individual characteristics of metabolism, the optimal level of fat is in the range of 20 ... 30% of the energy value of the diet, that is, it should not exceed 35 g per 1000 kcal of the diet. For a person with an average level of energy consumption, this corresponds to approximately 70 ... 100 g of fat per day.

Most of the lipid compounds of the human body can be synthesized if necessary. metabolic processes from carbohydrates. The exception is the essential polyunsaturated

fatty acids linoleic and linolenic, which are respectively in the co-6 and co-3 families. In this regard, both the total intake of PUFAs is normalized: it should be in the range of 3 ... 7% of the energy value of the diet, and the need for linoleic acid: 6 ... 10 r / day (this amount is contained in 1 tablespoon of vegetable oil). The standard for linolenic acid has not been established, but it must come at least 10% of the content of linoleic acid in food.

2-4. Carbohydrates and their importance in nutrition

Carbohydrates are the main energy-bearing macronutrients in human nutrition, providing 50...70% of the total energy value of the diet. They are capable of metabolizing to form high-energy compounds, both under aerobic and anaerobic conditions. As a result of the metabolism of 1 g of carbohydrates, the body receives energy equivalent to 4 kcal. The metabolism of carbohydrates is closely related to the metabolism of fats and proteins, which ensures their mutual transformations. With a moderate lack of carbohydrates in the diet, deposited fats, and with a deep deficiency (less than 50 r / day) and amino acids (both free and from the composition of muscle proteins) are involved in the process of gluconeogenesis, leading to obtaining the energy necessary for the body. In the opposite situation, liponeogenesis is activated and fatty acids are synthesized from excess carbohydrates, which are deposited in the depot.

Along with the main energy function, carbohydrates are involved in plastic metabolism. Glucose and its metabolites (sialic acids, amino sugars) are components of glycoproteins 5, which include most of the blood protein compounds (transferrin, immunoglobulins), a number of hormones, enzymes, and blood coagulation factors. Glycoproteins, as well as glycoligides, participate together with proteins and lipids in the structural and functional organization of biomembranes and at the same time play a leading role in the processes of cellular reception of hormones and other biologically active compounds and in intercellular interaction, which is essential for normal cell growth and differentiation. and immunity. Food carbohydrates are also precursors of glycogen and triglycerides; they serve as a source of carbon bases of non-essential amino acids, are involved in the construction of coenzymes, nucleic acids, adenosine triphosphate (ATP) and other biologically important compounds. Carbohydrates have an anti-ketogenic effect by stimulating the oxidation of acetyl coenzyme A, which is formed during the oxidation of fatty acids.

Carbohydrates are polyatomic aldehyde and keto alcohols. They are formed in plants during photosynthesis and enter the body mainly with plant products. However, added carbohydrates, which are most often represented by sucrose (or mixtures of other sugars) obtained industrially and then introduced into food formulations, are becoming increasingly important in nutrition.

All carbohydrates are divided according to the degree of polymerization into simple and complex. To simple include the so-called sugars - monosaccharides: hexoses (glucose, fructose, galactose), pentoses (xylose, ribose, deoxyribose) and disaccharides (lactose, maltose, galactose, sucrose).

complex carbohydrates are oligosaccharides, consisting of several (3...9) monosaccharide residues (raffinose, stachyose, lactulose, oligofructose) and polysaccharides. Polysaccharides are high-molecular polymeric compounds formed from a large number of monomers, which are monosaccharide residues. Polysaccharides are divided into starch and non-starch, which in turn can be soluble and insoluble.

Mono- and disaccharides. They have a sweet taste and are therefore called sugars. The degree of sweetness of different sugars is not the same. If the sweetness of sucrose is taken as 100%, then the sweetness of other sugars will be,%:

Fructose 173

Glucose 81

Maltose and galactose 32

Raffinoses 23

Lactose 16

Polysaccharides do not have a sweet taste.

Natural sources of simple carbohydrates are fruits, berries, vegetables, fruits, in some of which the sugar content reaches 4 ... 17% (Table 2.11).

Glucose(aldehyde alcohol) is the main structural monomer of all the most important polysaccharides - starch, glycogen, cellulose. It comes with nutrition in isolation as part of berries, fruits, fruits and vegetables, and also as a component of the most common disaccharides: sucrose, maltose, lactose. Glucose is quickly and almost completely absorbed in the gastrointestinal tract, enters the bloodstream and is carried to all organs and tissues for oxidation associated with the formation of energy. The level of glucose in the blood, along with the level of a number of amino acids, is a signal for the corresponding brain structures that model the appetite and eating behavior of a person. Excess glucose is rapidly converted into stored triglycerides.

Table 2.11

Fructose unlike glucose, it is a ketoalcohol and has a different distribution and metabolization dynamics in the body. It is almost twice as slowly absorbed in the intestines and is more retained in the liver. Fructose passes into glucose in cellular metabolic processes, but the increase in the concentration of glucose in the blood occurs smoothly and gradually, with less stress on the insular apparatus. At the same time, fructose has a shorter metabolic pathway compared to

ion with glucose is involved in the processes of liponeogenesis and promotes the deposition of fat in the depot. This explains a number of new facts obtained in the study of the positive dynamics of body weight in individuals who regularly consume foods enriched with food components containing fructose (maltodextrin corn syrups). Excessive intake of fructose leads to an increase in the blood concentration of C-peptide, which characterizes the degree of insulin resistance in the development of type 2 diabetes mellitus. Fructose is found in foods both in free form in honey and fruits, and in the form of fructose inulin polysaccharide in Jerusalem artichoke (earth pear), chicory and artichokes.

Galactose enters the body as part of milk sugar (lactose). It can be found free in some fermented dairy products such as yogurt. Galactose is converted in the liver to glucose.

The main industrially produced disaccharide is sucrose, or table sugar. The raw materials for its production are sugar beets (14 ... 25% sugar) and sugar cane (10 ... 15% sugar). Natural sources of sucrose in the diet are melons, watermelons, some vegetables, berries and fruits. Sucrose is easily digested and quickly breaks down into glucose and fructose, which are then involved in their inherent metabolic processes.

processes.

It is the use of sucrose as an essential component of many products (confectionery, sweets, jams, desserts, ice cream, soft drinks) that has now led to an increase in the share of mono- and disaccharides in the total volume of incoming carbohydrates in developed countries up to 50% and more (with the recommended 20%. As a result, against the background of decreasing energy consumption, the alimentary load on the insular apparatus increases, the level of insulin in the blood rises, fat deposition in the depot intensifies, and the blood lipid profile is disturbed. All this contributes to an increased risk of developing diabetes mellitus, obesity, atherosclerosis and numerous diseases based on the listed pathological conditions.

states.

Lactose is the main carbohydrate in milk and dairy products (consists of galactose and glucose molecules) and is of great importance as a source of carbohydrates for children. In adults, its share in the carbohydrate composition of the diet is significantly reduced due to the widespread use of other sources. In addition, in adults, and sometimes in children, the activity of the lactase enzyme, which breaks down milk sugar, is reduced. The consequences of intolerance to whole milk and products containing it are dyspeptic disorders. Used

Dietary intake of sour-milk products (kefir, yogurt, sour cream), as well as cottage cheese and cheese, as a rule, do not cause such a clinical picture. Milk intolerance is noted in 30-35% of the adult population of Europe, while among the inhabitants of Africa - more than 75%.

Maltose, or malt sugar, found in free form in honey, malt, beer, molasses and products made with the addition of molasses (confectionery and bakery products). In the body, maltose is an intermediate product and is formed as a result of the breakdown of polysaccharides in the gastrointestinal tract. It then dissimilates to two molecules of glucose. In some fruits (apples, pears, peaches) and a number of vegetables, the alcohol form of sugars is found - sorbitol, which is a reduced form of glucose. It is able to maintain the level of glucose in the blood without causing a feeling of hunger and without straining the insular apparatus. Sorbitol and other polyhydric alcohols such as xylitol, mannitol or their mixtures, having a sweet taste (30...40% of the sweetness of glucose), are used to produce a wide range of food products, primarily for the nutrition of patients diabetes and also chewing gum. The disadvantages of polyhydric alcohols include their effect on the intestines, which is expressed in a laxative effect and increased gas formation.

Oligosaccharides. Oligosaccharides, which include raffinose, stachyose, verbascose, are mainly found in legumes and products of their technological processing, such as soy flour, and also in small quantities in many vegetables. Fructo-oligosaccharides are found in grains (wheat, rye), vegetables (onions, garlic, artichokes, asparagus, rhubarb, chicory), as well as bananas and honey. The group of oligosaccharides also includes maltodextrins, which are the main components of syrups and molasses industrially produced from polysaccharide raw materials. One of the representatives of oligosaccharides is lactulose, which is formed from lactose during the heat treatment of milk, for example, in the production of baked and sterilized milk.

Oligosaccharides are practically not broken down in the human small intestine due to the lack of appropriate enzymes. For this reason, they have the properties of dietary fiber. Some Oligosaccharides play an essential role in the life of the normal microflora of the large intestine, which allows them to be classified as prebiotics - substances that are partially fermented by some intestinal microorganisms and ensure the maintenance of normal intestinal microbiocenosis.

Polysaccharides. The main digestible polysaccharide is starch - food base of cereals, legumes and potatoes. 56

It is a complex polymer (as a monomer, to which glucose is located), consisting of two fractions: amylose - a linear polymer (200 ... 2000 monomers) and amylopectin - a branched polymer (10,000 ... 1,000,000 monomers ). It is the ratio of these two fractions in various raw sources of starch that determines its various physicochemical and technological characteristics, in particular, solubility in water at different temperatures.

To facilitate the absorption of starch by the body, the product containing it must be subjected to heat treatment. In this case, a starch paste is formed in an explicit form, for example jelly, or in a latent form as part of a food composition: porridge, bread, pasta, legume dishes. Starch polysaccharides that enter the body with food undergo sequential, starting from the oral cavity, fermentation to maltodextrins, maltose and glucose, followed by almost complete assimilation. Starch is dissimilated by the body for a sufficiently long period and, unlike mono- and disaccharides, does not provide such a rapid and pronounced increase in blood glucose levels. However, the main food sources of starch polysaccharides (bread, cereals, pasta, legumes, potatoes) supply the body with significant amounts of amino acids, vitamins and minerals and minimum fat. At the same time, sugar not only does not contain essential nutrients, but also requires deficient vitamins and other micronutrients for its metabolism in the body. Most sweet confectionery products are also sources of hidden fat (cakes, pastries, waffles, butter cookies, chocolate).

In the process of heat treatment (baking, boiling) and cooling, the so-called resistant(resistant to digestion) starch, the amount of which depends both on the degree of heat load and on the content of amylose in the starch. Digestion-resistant starches are also found in natural products - their maximum amount is found in legumes and potatoes. Together with oligosaccharides and non-starch polysaccharides, they form the carbohydrate group of dietary fiber.

In recent years, there has been an increase in the amount of Food Industry so-called modified starches. They differ from natural forms in their good solubility in water (regardless of temperature). This is achieved by their preliminary industrial fermentation with the formation of various dextrins in the final composition. Modified starches are used in the form food additives to achieve a number of technological goals: giving the product a desired appearance

and stable shape, achieving the required viscosity and uniformity.

The second digestible polysaccharide is glycogen. Its nutritional value is small - no more than 10 ... 15 g of glycogen in the composition of the liver, meat and fish comes from the diet. As meat matures, glycogen is converted to lactic acid.

In humans, excess glucose in the first place (before metabolic transformation into fat) is converted into glycogen, the only reserve carbohydrate in animal tissues. In the human body, the total glycogen content is about 500 g ("/ 3 in the liver, the rest in the muscles) - this is the daily supply of carbohydrates used when they are deeply deficient in nutrition. Prolonged glycogen deficiency in the liver leads to dysfunction of hepatocytes and its fatty infiltration.

The magnitude of the need for carbohydrates for a person is determined by their leading role in providing the body with energy and the undesirability of the synthesis of glucose from fats (and even more so from proteins) and is directly dependent on energy consumption. Taking into account the possible individual characteristics of metabolism and the level of fat intake, the optimal level of carbohydrates in the diet is in the range of 55 ... 65% of the energy value of the diet, i.e. averages 150 g per 1000 kcal of diet. For a person with an average level of energy consumption, this corresponds to approximately 300 ... 400 g of carbohydrates per day.

The need of a person with an energy expenditure of 2,800 kcal for carbohydrates and their optimal group balance can be mainly ensured:

1) daily consumption."

360 g of bread and bakery products;

300 g potatoes;

400 g of vegetables, herbs, legumes;

200 g of fruits, berries;

no more than 60 g of sugar (the less, the better);

2) weekly intake:

175 g of cereals;

140 g pasta.

An assessment of the adequacy of meeting the real need for carbohydrates in an adult should be carried out using indicator parameters of nutritional status: body mass index and the level of glycated hemoglobin A 1c, an increase in the concentration of which indicates prolonged excessive consumption of sugars, including in a healthy person.

From the standpoint of assessing the possible impact of the carbohydrate component of the diet on the nutritional status parameters that characterize carbohydrate metabolism, it is advisable to use data on the so-called glycemic index(GI) - percentage,

reflecting the difference in the change in the concentration of glucose in the blood serum within 2 hours after the use of any product compared to the same result after the use of the test product. Glucose (50 g) or wheat bread (serving containing 50 g of starch) is usually used as a test product.

The glycemic index of foods (Table 2.12) depends on many nutritional factors:

The chemical structure and form of carbohydrates that make up the product;

Table 2.12

Serving including 50 G carbohydrates.

Glycemic index of some foods

the presence in the food product of proteins, fats, indigestible components, organic acids;

method of culinary, including thermal, processing of the product.

Complex carbohydrates can have a GI approaching or even exceeding that of simple carbohydrates for some mono- and disaccharides. The level of glycemia after the use of starch-containing products depends, among other things, on the ratio of amylose and amylopectin in starch: the rate of digestion and assimilation of amylopectin is less than that of amylose.

Information about the GI value of a product is important not only for patients with diabetes mellitus, but is also useful to any consumer from the standpoint of preventing excessive alimentary glycemia. It is advisable to put this information on the label of products containing carbohydrates.

non-starch polysaccharides. Non-starch polysaccharides (NPS) are widely distributed plant substances. Their chemical composition includes mixtures of various polysaccharides containing pentoses (xylose and arabinose), hexoses (rhamnose, mannose, glucose, galactose) and uronic acids. A number of them are contained in cell membranes, playing a structural role, others are in the form of gums and mucus inside and on the surface of plant cells.

According to the classification, NPS are divided into several groups: cellulose, hemicellulose, pectins, p-glycans and hydrocolloids (gums, mucus).

Non-starch polysaccharides are not digested in the human small intestine due to the lack of appropriate enzyme systems, for this reason they were previously called “ballast substances”, being recognized as excess food components, the removal of which during the technological processing of food raw materials was considered quite acceptable. This misconception, along with other purely technological reasons, has contributed to the emergence of a wide range of refined (purified from NSP) foods with significantly lower nutritional values. At present, there is no doubt that NPS play a significant role in the life support of the body, both at the functional and metabolic levels, which makes it possible to classify them as indispensable factors in human nutrition.

In animals, as the only exception, only one group of indigestible carbohydrate polymers consisting of acetylated glycosamine is found - chitin and chitosan, the food sources of which are the shell of crabs and lobsters (can be used as a food fortifier).

Lignin, a water-insoluble compound of non-carbohydrate (polyphenolic) nature, which is part of the cell membranes of many plants and seeds, also has similar properties.

Alimentary fiber. All of the NPS listed above, lignin and chitin, together with oligosaccharides and indigestible starch, are currently combined into one common heterogeneous group of nutrients called dietary fibers (DF). In this way, alimentary fiber- These are edible food components, mainly of a plant nature, resistant to digestion and assimilation in the small intestine, but undergoing complete or partial fermentation in the large intestine.

Legumes, grains, nuts, and fruits, vegetables, and berries are good sources of HP in the diet (Table 2.13). The higher the degree of purification (refining) of food raw materials during technological processing, the less HP (as well as many micronutrients) remains in the final product. This fact is clearly illustrated by the example of grain processing products: wheat contains 2.5 g of HP (per 100 g); in wheat flour, g: wholemeal - 1.9, 2nd grade - 0.6, 1st grade - 0.2, premium - 0.1; in bread (depending on the type of flour 0.1 ... 1.7); in oats - 10.7 g; in oatmeal - 2.8, in oatmeal - 1.3.

Health food at chronic diseases Kaganov Boris Samuilovich

1.4. The biological role of fat and its most important sources

Fats are very important integral part human diet. They are divided into neutral fats and fat-like substances (phospholipids, sterols).

Neutral Fats composed of glycerol and fatty acids.

Fatty acid are saturated (palmitic, stearic, myristic, oily, caproic, etc.) and unsaturated (oleic, linoleic, arachidonic, etc.). Natural fats contain more than 60 types of fatty acids.

The physiological role of fats in the body is great. First of all, fat is a valuable source of energy. His the energy value 2.5 times higher than proteins and carbohydrates: 1 g of fat when oxidized in the body gives 9 kcal (37.7 kJ). Fatty acids (along with glucose) are a source of energy for working muscles.

Fats and fat-like substances are part of the cells of organs and tissues. With dietary fat, the body receives fat-soluble vitamins A, D, E, K, essential fatty acids, phosphatides, cholesterol, and choline. Of great importance are the culinary properties of fat: fats improve the taste of food and cause a feeling of satiety.

Fat that enters the body with food, as well as synthesized in the body itself with excessive caloric nutrition, is deposited in fat depots as energy reserves, which are consumed during malnutrition or complete starvation. Even with normal body weight, body fat reserves are 7-9 kg and can provide the energy needs of a person with complete starvation for almost a month.

Dietary fats are divided into two types that differ significantly in their properties and value: animal fats (butter, beef, pork, mutton fat, etc.) and vegetable fats (sunflower, corn, olive, soybean and other oils). Each has qualities that are useful for a person, but neither one nor the other fat, taken separately, can fully meet the needs of the body. Dairy fats are a source of vitamins A, D, vegetable oils - vitamin E. In smaller quantities, vitamins are found in other animal fats. Therefore, only a combination of various fats will help eliminate deficiencies. certain types fat and provide the body with all the necessary fatty components.

Saturated fatty acids (SFAs). Their source in food is fat, butter, milk fat, meat, sausages, Coconut oil. The more saturated fatty acids, the higher the melting point of the fat, the longer its digestion and the less absorption. Therefore, more refractory fats (mutton, beef fat, lard) are more difficult to digest and absorb worse than other types of fats. In diseases of the digestive system of adolescents, mutton, pork, beef fats are excluded from the diet.

Monounsaturated fatty acids (MUFAs). A representative of this type of fatty acid is oleic acid, found predominantly in olive oil. long time they were considered as neutral fats with little effect on cholesterol metabolism in the body. However, it was found that the prevalence cardiovascular diseases in countries whose population consumes mainly olive oil, is low despite an increase in the total amount of fat in their diet.

Polyunsaturated fatty acids (PUFAs) are indispensable nutritional factors, since they are not synthesized in the body and come only with food, mainly with vegetable oils, to a lesser extent with legumes, nuts, sea ​​fish. At one time, these fatty acids were called vitamin F. Their role in human life is great. These substances are the active part of cell membranes, regulate metabolism, in particular the exchange of cholesterol, phospholipids, and a number of vitamins. The content of polyunsaturated fatty acids in food depends on cell growth, the state of skin, fat metabolism in the liver and many other processes in the body, while the growing body is most sensitive to their deficiency.

Polyunsaturated fatty acids are divided into two subclasses: the omega-6 family and the omega-3 family. Member of the omega-6 fatty acid family is linoleic acid from which arachidonic acid is synthesized in the body.

A person's need for polyunsaturated fatty acids is 2-6 g per day (for example, this amount is contained in 10-15 g of vegetable oil). To create some excess of essential linoleic acid, it is recommended to enter into daily ration 20-25 g of vegetable oil, which is approximately one third of the total amount of fat in the diet.

The omega-3 family includes fatty acids found in large quantities in fish and marine animal oils, as well as in linseed oil, walnuts. They are essential for health various groups population, including adolescents.

An important constituent of vegetable oils are phosphatides They are part of the cell membranes and affect their permeability (the exchange of substances between the cell and the extracellular fluid depends on this). Their content is especially high in the brain, nerve cells.

The most well-known phosphatide is lecithin. It can be synthesized in the body, but with a long-term absence of phosphatides in food (especially with a simultaneous deficiency of protein in the diet), a violation of fat metabolism occurs with the accumulation of fat in the liver.

Highly important property lecithin is its ability to lower blood cholesterol and prevent its deposition in vascular wall, that is, to prevent atherosclerotic changes in blood vessels. Eggs, liver, caviar, rabbit meat, fatty herring, unrefined vegetable oils are rich in lecithin.

in natural fats and in many food products contains a certain amount of fat-like substance cholesterol which is a normal part of most cells healthy body. In the body, it is used to form a number of biologically active substances, including sex hormones, adrenal hormones, and bile acids. Especially a lot of cholesterol in the tissues of the brain - more than 2 %.

Cholesterol is found in many animal products (eggs, meat, milk and dairy products, butter) and is practically absent in plant products. It does not belong to essential food substances, as it is easily synthesized in the body from the products of oxidation of carbohydrates and fats.

The need for fats depends on gender, age, nature of work, physical activity.

Average physiological need in fats for a healthy person is about 30% of the total calorie intake, or about 1-1.5 g of fat per 1 kg of body weight. That is, for a person with a body weight of 70 kg, it is 70-105 g per day, of which two-thirds are provided by animal fats and one-third by vegetable oils rich in linoleic acid (sunflower, corn, soy). Considering that the daily energy requirement for girls on average corresponds to 2600 kcal, for boys - 2900 kcal, the need for fat for them is on average 90-100 g per day, while, as noted above, 30% of the total amount of fat should come from vegetable fats.

The chemical composition of the products used as the main sources of fat is presented in Table 2.

table 2

The chemical composition of products used as the main sources of fat (per 100 g of product) and their energy value

An analysis of statistical data characterizing the nutrition of the population in economically developed countries, including our country, shows an increase in fat consumption up to 40-45 % from the total calorie content of the diet, mainly due to an increase in the amount of animal fat. Excess consumption of fats rich in saturated fatty acids bad influence on human health, contributes to the development of cardiovascular diseases, the appearance overweight body, obesity and other diseases.