Fats are found both in animal organisms and in plants. They are esters of trihydric alcohol (glycerol) and acids (oleic, stearic, linoleic, linolenic and palmitic). This is proved by their breakdown into acids and glycerin, as well as the synthesis of fats from the described compounds.
The formation of fats in the human body
Fats are glycerol esters. In the digestive process, they are emulsified with bile salts and come into contact with enzymes by which they are hydrolyzed. Thus, the released fatty acids are absorbed into the mucosa of the digestive tract, which is the end of the fat synthesis process. After this, fat passes through the entire portal system of the body as microparticles that bind to proteins in the blood. Metabolism occurs in the liver.
Fat synthesis is possible due to excess carbohydrates that are not involved in the formation of glycogen. In addition, lipids are derived from certain amino acids.
Compared to glycogen, fats are a compact storage of energy. However, it is not limited in any way, since it has the appearance of neutral lipids in fat cells. Lipogenesis occurs due to the synthesis of fatty acids, since they are found in almost all lipid groups.
Stages of lipid metabolism
Fats and fat-like compounds pass through the following cycle in the human body:
- ingestion with food;
- decay into simpler compounds, digestion process, absorption;
- transfer from the digestive system using chyloproteins;
- the exchange of a complex protein represented by neutral fats, fatty acids, cholesterides or phospholipids;
- exchange of complex lipids, esters of polyhydric alcohols and higher fatty acids;
- metabolism of polycyclic lipophilic alcohol;
- the mutual transition of fatty acids and ketone bodies;
- the process of converting acetyl-CoA to fatty acids;
- the breakdown of fats into components under the action of lipase;
- degradation of fatty acid decomposition products.
The importance of fatty acids for the human body
Phospholipids are important for the normal synthesis of fats in the human body. With their lack, metabolic processes in the liver are inhibited.
Phospholipids break down into glycerin, fatty acids, phosphoric acid and nitrogenous bases. The first two substances can either turn into water and carbon dioxide, or participate in the synthesis of fats.
Choline (a nitrogenous base) is important for the formation of methionine and creatine. Methionine is necessary for the normal functioning of the liver, lowering blood cholesterol, as well as an antidepressant effect. Creatine is responsible for energy metabolism in muscle and nerve cells. Acetylcholine (a product of choline) normalizes the transmission of nervous excitement.
It is fats that give energy to adesyntrophosphate molecules, which are responsible for all biochemical processes in the body.
Thus, the synthesis of fats in cell membranes is important for the occurrence of numerous chemical reactions. Without them, the human body will not be able to function normally.
Causes of Fat Digestion Disorders
Failures in the absorption of fats can be caused by the following reasons:
- Blockage of the bile duct, leading to problems with secretion. Caused by a similar condition may be the presence of stones or tumors. Reduced production of bile secretion leads to difficulties in mixing fats and, thus, the inability to hydrolyze fatty compounds.
- Problems with juice production in the pancreas. It also affects the hydrolysis of fats.
Each of the problems described above leads to an increase in the amount of fat in solid human products. There is a so-called "fat stool". This condition is fraught with the fact that fat-soluble vitamins A, E, D and K cease to be absorbed, as well as fatty acids that are extremely important for the body. Prolonged "fatty stools" leads to the deficiency of these substances and the development of relevant clinical symptoms.
Also, a failure in the digestion of fats leads to difficulties in the assimilation of non-lipid substances, since fat tends to envelop food, which prevents the action of enzymes on it.
Fat Disorders Disease
Impaired lipid metabolism can lead to the following conditions:
- Obesity. It occurs both in violation of eating habits associated with a sedentary lifestyle, and in the presence of hormonal imbalance.
- Abetalipoproteinemia. A rare hereditary disease in which certain lipoproteins are absent in the blood. Fats accumulate in the mucosa. The deformation of red blood cells develops.
- Cachexia. Low calorie intake leads to a decrease in adipose tissue in the body. This condition can occur in the presence of tumors, in case of chronic diseases of an infectious nature, poor nutrition or metabolic failures.
- Atherosclerosis. Chronic arterial disease caused by impaired lipid metabolism, associated with the deposition of cholesterol plaques on the vascular walls. In the future, this is fraught with the appearance of sclerosis (proliferation of connective tissue), which leads to deformation of the vessels up to their complete blockage. Atherosclerosis provokes coronary heart disease.
- Menkeberg arteriosclerosis. This disease is similar to atherosclerosis. However, its fundamental difference is that the vessels are deformed and clogged not under the influence of connective tissues, but because of calcification - accumulation of salt deposits. With this lesion, plaques do not form. In addition, the disease provokes other complications, the main of which is aneurysm.
Synthesis of fats in plant cells
Metabolic processes in plant tissues undergo changes at the end of the flowering period. When protein synthesis weakens, fats begin to form from carbohydrates. This process proceeds until the seeds fully ripen. The synthesis of fats from carbohydrates and the synthesis of proteins from amino acids are important for the breeding season.
Oil crops are characterized by the highest fat content. This must be taken into account by the fact that he wants to adjust his own weight.
Lipid metabolism in science
Today, the synthesis of fats suitable for nutrition is possible by esterification with glycerol of fatty acids, which, in turn, are created by the oxidation of paraffins. Since both fatty acids and glycerin are obtained from coal, there is a real way to carry out a complete synthesis of dietary fats. These discoveries became possible thanks to the work of F. Weler, A. V. G. Kolbe, M. Bertlo and A. M. Butlerov. It was they who proved the connection of organic and inorganic substances, as well as the possibility of their interconversion.
The knowledge gained is successfully applied in the food, pharmaceutical and chemical industries. However, today it is more expedient to obtain fats from natural sources (plant and animal), since synthesis is not a profitable economic procedure.