Fats: structure, functions, properties, sources for the body

The main components of all living cells are proteins, fats, carbohydrates. The structure, functions and properties of these compounds ensure the vital activity of organisms living on our planet.

Fats are natural organic compounds , complete glycerol esters of fatty acids with a single base. They belong to the lipid group. These compounds perform a number of important functions of the body and are an indispensable component in the human diet.

Classification

Fats, whose structure and properties allow them to be used for food, are inherently divided into animal and vegetable. The latter are called oils. Due to the high content of unsaturated fatty acids in them, they are in a liquid aggregate state. Exception - palm oil.

By the presence of certain acids, fats are divided into saturated (stearic, palmitic) and unsaturated (oleic, arachidonic, linolenic, palmitoleic, linoleic).

Structure

The structure of fats is a complex of triglycerides and lipoid substances. The latter are phospholipid compounds and sterols. Triglyceride is an ester compound of glycerol and fatty acid, the structure and characteristics of which determine the properties of fat.

The structure of the fat molecule in general form is represented by the formula:

CH2-OˉCO-R & apos;

I

CHˉO-CO-R "

I

CH2-OˉCO-R '",

In which R is a fatty acid radical.

The composition and structure of fats have in their structure three unbranched radicals with an even number of carbon atoms. Saturated fatty acids are most often represented by stearic and palmitic acids , unsaturated fatty acids are linoleic, oleic and linolenic.

Properties

Fats, the structure and properties of which are determined by the presence of saturated and unsaturated fatty acids, have physical and chemical characteristics. They do not interact with water, but completely decompose in organic solvents. Saponified (hydrolyzed) if they are treated with steam, mineral acid or alkalis. During this reaction, fatty acids or their salts and glycerin are formed. Form the emulsion after intensive shaking with water, an example of this is milk.

Fats have an energy value of approximately 9.1 kcal / g or 38 kJ / g. If you translate these values into physical indicators, then the energy released at a consumption of 1 g of fat would be enough to raise 1 meter of cargo weighing 3900 kg.

Fats, the structure of their molecules determine their basic properties, have a high energy intensity when compared with carbohydrates or proteins. Complete oxidation of 1 g of fat by the release of water and carbon dioxide is accompanied by the production of energy twice the combustion of sugars. To break down fats, carbohydrates and oxygen are needed in a certain amount.

In the human body and other mammals, fats are one of the most significant energy suppliers. In order for them to be sucked in the intestine, it is necessary to emulsify them with the help of bile salts.

Functions

Fats play an important role in the mammalian organism, the structure and functions of these compounds in organs and systems have different meanings:

1. Supply of energy. This function is the main one for fats. Due to their high energy value, they are the best supplier of "fuel". Reserves are created through deposition in the form of deposits.
2. Protection. Fatty tissues envelop the organs and thus prevent their injury and shaking, soften and amortize external influences.
3. Thermal insulation. Fats have a low thermal conductivity and therefore preserve the body heat well and protect it from hypothermia.

In addition to these three basic functions, fats perform several private ones. These compounds support the vital activity of cells, for example, provide elasticity and a healthy appearance of the skin, improve the functioning of the brain. Membrane cell formations and subcellular organelles retain their structure and function through the participation of fats. Vitamins A, D, E and K can only be absorbed in their presence. Growth, development and reproductive function also largely depend on the availability of fats.

Need of an organism

About a third of the energy costs of the body are replenished by fats, the structure of which allows to solve this problem with a properly organized diet. The calculation of the daily requirement takes into account the type of activity and the age of the person. Therefore, most of the fats are needed for young people who lead an active lifestyle, for example, athletes or men engaged in heavy physical labor. With a sedentary lifestyle or a tendency to fullness, their quantity should be reduced in order to avoid obesity and accompanying problems.

It is also important to take into account the structure of fats. Essential is the ratio of unsaturated and saturated acids. The latter, if over-consumed, disrupt fat metabolism, the functioning of the gastrointestinal tract, increase the possibility of the appearance of atherosclerosis. Unsaturated acids have the opposite effect: they restore normal metabolism, remove cholesterol. But the abuse of them leads to a disorder of digestion, the appearance of stones in the gallbladder and the excretory pathways.

Sources

Almost all foods contain fats, their structure can be different. The exception is vegetables, fruits, alcoholic beverages, honey and some others. Products are divided into:

• Oily (40 grams and more in 100 g of product). This group includes oil, margarine, lard, fat meats, some types of sausages, nuts, etc.
• Average fat content (from 20 to 40 g in 100 g of product). The group is represented by cream, fatty sour cream, homemade cottage cheese, some kinds of cheeses, sausages and sausages, goose meat, chocolate, cakes, halva and other sweets.
• Low fat content (20 grams or less per 100 g of product). Rice, buckwheat, beans, beans, bread, chicken meat, eggs, fish, mushrooms, most of dairy products, etc. are included.

Also important is the chemical structure of fats, which determines the presence of this or that acid. On this basis, they can be saturated, unsaturated and polyunsaturated. The former are found in meat products, fat, chocolate, melted fat, palm, coconut and butter. Unsaturated acids are present in poultry meat, olives, cashews, peanuts, olive oil. Polyunsaturated - in walnuts, almonds, pecans, seeds, fish, as well as in sunflower, linseed, rapeseed, corn, cottonseed and soybean oil.

Rationing

The peculiarities of the structure of fats require that a number of rules be observed when compiling a diet. Nutritionists recommend adhering to the following ratio:

• Monounsaturated - up to half the total amount of fats;
• Polyunsaturated - a quarter;
• Saturated - a quarter.

In this case, vegetable fats should account for about 40% of the diet, and the animal - 60-70%. Elderly people need to increase the number of the first to 60%.

The maximum limit or completely exclude from the diet is trans fats. They are widely used in the production of sauces, mayonnaise, confectionery. Fat is subjected to intense heating and oxidation. They can be found in french fries, chips, donuts, pies, etc. Of this list are the most dangerous products, the preparation of which occurred on rancid or repeatedly used oil.

Useful qualities

Fats, the structure of which provides about half of the body's energy, has many useful qualities:

• Cholesterol promotes a better carbohydrate metabolism and ensures the synthesis of vital compounds - under its influence, steroid hormones of the adrenal glands are produced;
• About 30% of all heat in the human body is produced by brown fat, a tissue located in the neck and back of the back;
• Badgers and canola lard refractory, are cured of respiratory diseases, including tuberculosis of the lungs;
• Phospholipid and glucolipid compounds are included in all tissues, synthesized in the digestive organs and counteract the formation of cholesterol plaques, support the functioning of the liver;
• Thanks to phosphatides and sterols, the constant composition of the cytoplasmic base of the cells of the nervous system is maintained and vitamin D is synthesized.

Thus, fats are an indispensable component in the human diet.

Excess and Deficiency

The fats, structure and functions of these compounds benefit only with moderate consumption. Their excess contributes to the development of obesity - a problem that is relevant for all developed countries. This disease leads to an increase in body weight, decreased mobility and deterioration of well-being. Increased risk of atherosclerosis, cardiac ischemia, hypertension. Obesity and its consequences are more likely than other diseases to lead to death.

Deficiency of fats in the diet contributes to the deterioration of the skin, slows the growth and development of the child's body, disrupts the functioning of the reproductive system, prevents the normal exchange of cholesterol, provokes atherosclerosis, worsens the brain and nervous system in general.

Proper planning of the diet, taking into account the body's needs for fats, will help to avoid many diseases and improve the quality of life. Essential is the moderate consumption, without excess and deficiency.