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, full esters of glycerol and single base fatty acids. They belong to the group of lipids. These compounds perform a number of important bodily functions and are an indispensable component in the human diet.
Classification
Fats, the structure and properties of which allow them to be used as food, are by nature 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 state of aggregation. The exception is palm oil.
By the presence of certain acids, fats are divided into saturated (stearic, palmitic) and unsaturated (oleic, arachidonic, linolenic, palmitoleic, linoleic).
Building
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 a fatty acid, the structure and characteristics of whichproperties of fat are determined.
The structure of a fat molecule in general is displayed by the formula:
CH2-OˉCO-R’
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, unsaturated - 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 features. They do not interact with water, but completely decompose in organic solvents. They are saponified (hydrolyzed) if they are treated with steam, mineral acid or alkalis. During this reaction, fatty acids or their s alts and glycerol are formed. Forms an emulsion after vigorous shaking with water, milk is an example.
Fats have an energy value of approximately 9.1 kcal/g or 38 kJ/g. If we translate these values into physical indicators, then the energy released at the expense of 1 g of fat would be enough to lift a load weighing 3900 kg by 1 meter.
Fats, the structure of their molecules determines their basic properties, have a high energy intensity when compared with carbohydrates or proteins. Complete oxidation of 1 g of fat with the release of water and carbon dioxide is accompanied by energy production twice as high ascombustion of sugars. For the breakdown of fats, carbohydrates and oxygen are needed in a certain amount.
In humans and other mammals, fats are one of the most important energy providers. In order for them to be absorbed in the intestines, they must be emulsified with bile s alts.
Functions
In the body of mammals, fats play an important role, the structure and functions of these compounds in organs and systems have different meanings:
- Energy supply. This function is the main one for fats. Due to their high energy value, they are the best supplier of "fuel". Reserves are created by depositing in the form of deposits.
- Protection. Adipose tissue envelops the organs and thus prevents them from injury and shaking, softens and absorbs external influences.
- Thermal insulation. Fats have low thermal conductivity and therefore retain body heat well and protect it from hypothermia.
In addition to these three main functions, fats perform several private ones. These compounds support the vital activity of cells, for example, provide elasticity and a he althy appearance of the skin, improve brain function. Membrane cell formations and subcellular organelles retain their structure and functioning due to the participation of fats. Vitamins A, D, E and K can only be absorbed in their presence. Growth, development and reproductive function are also largely dependent on the presence of fats.
Body needs
About a thirdThe energy consumption of the body is replenished by fats, the structure of which allows solving this problem with a properly organized diet. The calculation of the daily requirement takes into account the type of activity and age of the person. Therefore, most fats are necessary for young people who lead an active lifestyle, for example, athletes or men engaged in hard physical labor. With a sedentary lifestyle or a tendency to be overweight, their number should be reduced to avoid obesity and related problems.
It is also important to consider the structure of fats. The ratio of unsaturated and saturated acids is essential. The latter, when consumed excessively, disrupt fat metabolism, the functioning of the gastrointestinal tract, and increase the possibility of atherosclerosis. Unsaturated acids have the opposite effect: they restore normal metabolism, remove cholesterol. But their abuse leads to indigestion, the appearance of stones in the gallbladder and excretory tract.
Sources
Almost all products contain fats, while their structure may be different. The exceptions are vegetables, fruits, alcoholic beverages, honey and some others. Products are divided into:
- Fatty (40 grams or more per 100 g of product). This group includes butter, margarine, lard, fatty meats, some types of sausages, nuts, etc.
- Medium fat (from 20 to 40 g per 100 g of product). The group is represented by cream, fat sour cream, cottage cheese, some types of cheese, sausages and sausages, meatgoose, chocolate, cakes, halva and other sweets.
- Low fat (20 grams or less per 100g of product). These include: rice, buckwheat, beans, beans, bread, chicken meat, eggs, fish, mushrooms, most dairy products, etc.
Also important is the chemical structure of fats, which determines the presence of a particular acid. On this basis, they can be saturated, unsaturated and polyunsaturated. The former are found in meat products, lard, chocolate, lard, 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 oils.
Meeting
Features of the structure of fats require you to follow a number of rules when compiling a diet. Nutritionists recommend following their ratio:
- Monounsaturated - up to half of total fat;
- Polyunsaturated - a quarter;
- Rich - a quarter.
In this case, vegetable fats should be about 40% of the diet, animal - 60-70%. Older people need to increase the number of the first to 60%.
It is worth limiting or completely eliminating trans fats from the diet. They are widely used in the production of sauces, mayonnaise, confectionery. Fats subjected to intensive heating and oxidation are harmful. They can be found in french fries, chips, donuts,pies, etc. Of this list, the most dangerous products are those cooked in rancid or reused oil.
Useful qualities
Fats, whose structure provides about half of the body's energy, have many useful qualities:
- cholesterol promotes 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, tissue located in the neck and upper back;
- badger and dog fat are refractory, cure respiratory diseases, including tuberculosis of the lungs;
- phospholipid and glucolipid compounds are found 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 unchanged composition of the cytoplasmic basis of the cells of the nervous system is maintained and vitamin D is synthesized.
Thus, fats are an indispensable component in the human diet.
Surplus and deficit
Fats, the structure and function of these compounds are only beneficial when consumed in moderation. 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, a decrease in mobility and a deterioration in well-being. An increased risk of developingatherosclerosis, cardiac ischemia, hypertension. Obesity and its consequences lead to death more often than other diseases.
Fat deficiency in the diet contributes to the deterioration of the skin, slows down the growth and development of the child's body, disrupts the functioning of the reproductive system, interferes with the normal metabolism of cholesterol, provoking atherosclerosis, impairs the functioning of the brain and nervous system as a whole.
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. It is their moderate consumption, without excess and deficiency, that is essential.
