Benefits and types of fatty acids
Fats are compounds of glycerin and acids. Usually, three fatty acids are attached to glycerin, which is why fats are also called triglycerides. The triglycerides contain about 9% glycerol and acids with different carbon chain lengths. The properties of triglycerides depend on the length and characteristics of the chemical structure of their constituent acids.
Types of acids
Fatty acids are divided into saturated and unsaturated. In saturated carbon, all chemical bonds are filled with hydrogen. Unsaturated bonds have one or more hydrogen-unsaturated bonds. That is, there is one or more double bonds between adjacent carbon atoms.
If there is only one unsaturated carbon bond in a fat molecule, it is called monounsaturated. When there are several unsaturated bonds, fatty acids are called polyunsaturated, and they also differ in the length of the carbon chain.
Palmitic and stearic acid
In food, palmitic and stearic ones are most often found. The largest amount of saturated fatty acids is found in animal fats. Beef contains 25% palmitic, 20% stearic, pork – 25% palmitic and 13% stearic, butter – 7% stearic, 25% palmitic and 8% mystric acids. Palmitic and oleic acids must necessarily enter the body.
All animal fats have a solid consistency at room temperature, as they have a high melting point. The more saturated fatty acids in the composition, the higher its melting point. Beef fat is harder than chicken fat, since beef fat contains 38% saturated acids, while chicken fat contains only 4%.
Of the monounsaturated ones, oleic acid is the most abundant. It is contained in olive oil – 65%, in margarines – 43-47%, pork fat – 43%, beef fat – 37%, butter – 23%, goose meat – 11-16%. Of the saturated fatty acids in vegetable fats, palmitic acid is most often found.
Linoleic, linolenic and archidonic fatty acids
The main representatives of polyunsaturated fatty acids are linoleic, linolenic and arhidonic.
Fats, which contain many unsaturated fatty acids, have a liquid consistency at room temperature, since they have a low melting point. These include mainly plant fats. Vegetable oils contain 99.9% fat, nuts – 53-65%, oatmeal – 6.1%, buckwheat – 3.3%. Fish oil also contains mono- and polyunsaturated fatty acids. For example, mackerel contains 15% fatty acids, of which 70 are monounsaturated. 4.50 – polyunsaturated, 3.50 – saturated.
Fatty acids that make up fats can be synthesized in the body from carbohydrates, less often from proteins. However, there are those that cannot be synthesized in the human body from intermediate metabolic products. For this reason, they are called irreplaceable. Essential fatty acids are linoleic and linolenic. Some authors also include arachidonic fatty acid among them. However, it is formed in the human body from linoleic acid with the participation of vitamin B. Vegetable oils contain mainly the precursor of arachidonic acid – linoleic fatty acid. A lot of arachidonic acid (up to 30%) is contained in fish oil. Arachidonic acid is a precursor of prostaglandins – tissue hormones, is involved in the activation of the blood coagulation and anticoagulation systems.
With a deficiency of essential polyunsaturated fatty acids in the diet, skin lesions, impaired capillary permeability, decreased immunity are observed, and in children, growth retardation.
The minimum body’s need for linoleic acid is 2-6 g, the optimum is 10 g. This need is provided by about 20 g of sunflower or corn oil, which contains about 60% linoleic acid. In animal fats, the largest amount of linoleic acid is found in pork fat – 9.1%. This acid is found in cereals, but in insignificant quantities: 1.5-2.5%.
Fatty acids: products containing them
The question often arises: which of the vegetable oils is the most useful? Of course, these are the oils that simultaneously contain essential oils – linoleic and linolenic.
The largest amount of linoleic and linolenic acids is contained in hemp oil – 53% and 18%, respectively, and in soybean oil – 51% of the first and 10% of the second. Mustard oil contains 18% linoleic and 5.5% linolenic fatty acids, rapeseed oil – 14%. A small amount of linolenic acid is contained in corn oil – 0.60%. The rest of the vegetable contains only linoleic acid, and linolenic acid is either absent or is found in negligible amounts.
Of great value is olive oil, the fats of which are of great value. Although it contains only 12% linoleic acid and only traces of linolenic acid, the presence of almost 65% monounsaturated oleic acid in it makes olive oil dietary. This is due to the fact that the high content of polyunsaturated fatty acids in the diet is an additional burden for fat metabolism. In addition, oils with a large amount of polyunsaturated acids can oxidize and turn rancid during prolonged storage, especially in light. Olive oil oxidizes much more slowly. Therefore, it is used in the manufacture of high-quality canned fish. With a rational diet, the ratio of various acids is distributed as follows: if the entire amount of fatty acids is taken as 100%, then 60% should be monounsaturated, 10% for polyunsaturated and 30% for saturated. With significant deviations from the recommended ratio, fat metabolism is disrupted. With a persistent increase in the level of cholesterol and other lipids in the blood, which is a risk factor for cardiovascular diseases and atherosclerosis, it is recommended not only to reduce the total fat intake but also to increase the proportion of unsaturated fatty acids – to replace refractory fats with vegetable oils.
Deficiency of essential acids can occur in infants when they are fed with unadapted formulas that do not correspond to breast milk, since the content of linoleic acid in human milk is 12-15 times higher than in cow’s milk.
In adults, such a deficiency can occur after complex surgical operations, when for a long time patients receive only intravenous nutrition with special mixtures containing only amino acids and glucose.
With a deficiency in the diet of linolenic acid, the synthesis of arachidonic fatty acid is disrupted, which is the main component of structural lipids that make up the cell membranes and intracellular structures. Changes in the composition of lipids in biological membranes contribute to the disruption of their functions. In particular, a change in their permeability develops, as a result of which the physiological mechanisms of the cells and the organism as a whole are disrupted.
In recent years, the important role in lipid metabolism of the so-called omega-3 and omega-6 polyunsaturated fatty acids has become known. They are referred to as essential biologically active food substances and are sometimes called vitamin F (from the English fat – fat).
The omega-3 class prevents the development of thrombosis. Their positive effect on fat metabolism in patients with diabetes, atherosclerosis, and ischemic heart disease has been shown. They have the ability to slightly lower blood pressure. Of the foodstuffs, vitamin F is found most in oily marine fish.
The omega-6 class includes linoleic, linolenic, arachidonic, and gamma-linoleic fatty acids. They are found mainly in vegetable oils. The role of the omega-6 class is manifold. They have a positive effect on cholesterol metabolism, normalize the functional activity of cell membranes. Their positive effect on immunity has been shown. The ratio of omega-6 to omega-3 fatty acids should be 3: 4.
Currently, omega-3 fatty acid preparations are derived from fish oil. These are eikonol, eifitol, poseidonol, the preparation of fats “Omega-3” and others. Fish oil itself in recent years has again become widely used in medical practice, not only in children, but also in adults.