The main components of all living cells are proteins, fats, carbohydrates. The structure, functions and properties of these compounds provide the vital activity of organisms that live on our planet.
Fats are naturally occurring organic compounds full of base esters of glycerol and fatty acids. They belong to the group of lipids. These compounds perform a number of important body functions and are an indispensable component in the human diet.
Classification
Fats, the structure and properties of which allow their use in food, are inherently divided into animal and vegetable. The latter are called oils. Due to the high content of unsaturated fatty acids in them are in the 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).
Structure
The structure of fats is a complex of triglycerides and lipoid substances. The latter are phospholipid compounds and sterols. Triglyceride is an ether compound of glycerol and a fatty acid, the structure and characteristics of which determine the properties of fat.
The structure of the 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.
The properties
Fats, the structure and properties of which are determined by the presence of saturated and unsaturated fatty acids, have physicochemical features. They do not interact with water, but are completely decomposed 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. They form an emulsion after vigorous agitation with water, for example, milk.
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 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 determines their basic properties, have a high energy intensity when compared with carbohydrates or proteins. The complete oxidation of 1 g of fat by the release of water and carbon dioxide is accompanied by the generation of energy twice as high as the combustion of sugars. To break down fats, carbohydrates and oxygen are needed in a certain amount.
In humans and other mammals, fats are one of the most significant energy suppliers. In order for them to be absorbed in the intestine, they must be emulsified using bile salts.
Functions
In 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 essential for fats. Due to their high energy value, they are the best supplier of "fuel". Stocks are created by deposits in the form of deposits.
- Protection. Adipose tissues envelop the organs and thereby prevent their injury and concussion, soften and absorb external influences.
- Thermal insulation. Fats have low thermal conductivity and therefore well retain body heat and protect it from hypothermia.
In addition to these three main functions, fats perform several private. These compounds support the vital activity of cells, for example, provide elasticity and a healthy appearance of the skin, improve brain function. Membrane cell formations and subcellular organelles retain their structure and function due to the participation of fats. Vitamins A, D, E and K are able to be absorbed only in their presence. Growth, development, and reproductive function also largely depend on the availability of fats.
Body need
About a third of the body's energy consumption is replaced by fats, the structure of which allows us to solve this problem with a properly organized diet. Calculation of daily needs takes into account the type of activity and age of the person. Therefore, most fats are necessary for young people leading an active lifestyle, for example, athletes or men engaged in heavy physical labor. With a sedentary lifestyle or a tendency to be overweight, their number must be reduced in order 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, with excessive consumption, disrupt fat metabolism, the functioning of the gastrointestinal tract, and increase the possibility of atherosclerosis. Unsaturated acids have the opposite effect: restore normal metabolism, remove cholesterol. But abuse of them leads to indigestion, the appearance of stones in the gallbladder and excretory tract.
Sources
Almost all products contain fats, their structure may be different. The exception is vegetables, fruits, alcoholic beverages, honey and some others. Products are divided into:
- Fatty (40 or more grams per 100 g of product). This group includes oil, margarine, lard, fatty meats, some types of sausages, nuts, etc.
- Medium fat (20 to 40 g per 100 g of product). The group is represented by cream, fat sour cream, homemade cottage cheese, some types of cheeses, sausages and sausages, goose meat, chocolate, cakes, halva and other sweets.
- Low fat content (20 or less grams per 100 g of product). They include: rice, buckwheat, beans, beans, bread, chicken meat, eggs, fish, mushrooms, most of 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 first are found in meat products, lard, chocolate, ghee, palm, coconut and butter. Unsaturated acids are present in poultry, olives, cashews, peanuts, olive oil. Polyunsaturated - in walnuts, almonds, pecans, seeds, fish, as well as in sunflower, flaxseed, rapeseed, corn, cottonseed and soybean oil.
Diet
Features of the structure of fats require you to follow a number of rules when compiling a diet. Nutritionists recommend adhering to the following ratio:
- Monounsaturated - up to half of the total amount of fat;
- Polyunsaturated - a quarter;
- Saturated - a quarter.
Moreover, vegetable fats should make up about 40% of the diet, animal - 60-70%. Elderly people need to increase the number of the first to 60%.
To limit or completely exclude from the diet is trans fats. They are widely used in the manufacture of sauces, mayonnaise, confectionery. Fats subjected to intense heating and oxidation are harmful. They can be found in french fries, chips, donuts, pies, etc. From this entire list, the most dangerous products are those that have been cooked with rancid or used oil many times.
Useful qualities
Fats, the structure of which provides about half of all body energy, have many useful qualities:
- cholesterol contributes to a better carbohydrate metabolism and provides 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 upper back;
- badger and canine fat refractory, cure respiratory diseases, including pulmonary tuberculosis;
- phospholipid and glucolipid compounds are part of all tissues, are 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 base of the cells of the nervous system is maintained and vitamin D.
Thus, fats are an indispensable component in the human diet.
Excess and deficit
The fats, structure, and functions of these compounds are beneficial 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, a decrease in mobility and a deterioration in well-being. The risk of developing atherosclerosis, cardiac ischemia, hypertension is increased. Obesity and its consequences more often than other diseases lead to death.
Deficiency of fat 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, interferes with the normal exchange of cholesterol, provoking atherosclerosis, worsens the functioning of the brain and nervous system as a whole.
Proper diet planning, taking into account the body's needs for fats, will help to avoid many diseases and improve the quality of life. Of moderate importance is their moderate consumption, without excess and deficit.