Cholesterol is an organic compound belonging to the class of sterols, in biological terms, this substance is one of the most important in the body.
Cholesterol has a large number of functions. This lipophilic alcohol forms the basis of the cell membrane and acts as a biolayer modifier. Due to its presence in the structure of the plasma membrane, the latter acquires a certain rigidity. This compound is a stabilizer of cell membrane fluidity.
In addition, cholesterol is involved:
- in the process of synthesis of steroid hormones;
- in the process of formation of bile acids;
- in the synthesis of vitamins of group D;
Additionally, this biologically active component regulates cell membrane permeability and protects red blood cells from the damaging effects of hemolytic toxins on them.
Cholesterol is an organic compound practically insoluble in water, therefore it is contained in the blood in the form of complexes with protein carriers. Such complexes are called lipoproteins.
There are several groups of complex compounds of proteins and cholesterol.
The main ones are as follows:
- LDL - low density lipoprotein.
- VLDL - very low density lipoproteins.
- HDL - high density lipoprotein.
LDL and VLDL are compounds capable of provoking the development of atherosclerosis and associated serious complications with a high concentration in the blood plasma.
Synthesis of cholesterol and the causes of increasing its blood levels
Cholesterol enters the internal environment of the body in the process of nutrition, as one of the components of food of animal origin.
In this way, about 20% of the total amount of the substance is delivered to the body.
This type of cholesterol has an endogenous origin.
Most of the cholesterol is synthesized by the body independently. Lipophilic alcohol, produced by cells of certain organs, has an exogenous origin.
Which organs produce cholesterol?
These bodies are:
- liver - synthesizes about 80% of cholesterol of exogenous origin;
- small intestine - provides synthesis of about 10% of the required amount of this bioactive component;
- kidneys, adrenal glands, sex glands and integuments jointly produce about 10% of the total amount of lipophilic alcohol required.
In the human body contains approximately 80% of the total amount of cholesterol in the bound form, and the remaining 20% in the free form.
Most often, violations of the level of cholesterol in the body are associated with the occurrence of malfunctions in the organs carrying out its biosynthesis.
The following factors may contribute to the appearance of excess lipids in addition to eating fatty foods:
- Insufficient production of bile acids by the liver cells, the main component of which is lipophilic alcohol, leads to the accumulation of excess of this substance in the blood plasma and the formation of cholesterol deposits on the walls of blood vessels of the circulatory system in the form of plaques.
- The lack of protein components necessary for the synthesis of HDL complexes by the liver leads to an imbalance between LDL and HDL. The balance shifts towards increasing the amount of LDL.
- Excess cholesterol in the consumed food leads to an increase in the level of LDL in plasma.
- The deterioration of the ability of the liver to synthesize and remove bile and excess cholesterol with it in the feces, which contributes to the accumulation of cholesterol and the development of atherosclerosis, fatty hepatosis, and dysbacteriosis due to the reproduction of pathogenic microflora.
If the rules of nutrition are observed, and the level of lipids is different from normal, it is recommended to contact the health facility to conduct an examination and identify the reasons that provoked the occurrence of a pathological condition.
Intestinal microflora and cholesterol
The normal circulation of bile acids can be disturbed as a result of the development of deep microbiological pathologies in the intestine.
It is reliably known that normal microflora contributes to the implementation of bile acid recycling processes and the regulation of cholesterol in the blood plasma.
Some bacterial autostrains, the native microflora of the intestinal cavity, are actively involved in the synthesis of lipophilic alcohol, some microorganisms transform this compound, and some destroy it and excrete it.
As a result of the impact on the body of a stressful situation, the processes are accompanied by accelerated reproduction of putrefactive microflora in the small intestine.
The stressful situation can be triggered by various factors, the main ones being the following:
- negative psychological impact;
- negative impact as a result of the development of an infectious process;
- negative impact on the internal environment as a result of the development of worms.
All of these negative factors lead to increased levels of intoxication, under the influence of which the processes of binding and release of bile acids are disrupted. This negative effect provokes increased absorption of bile acids. The result of such a negative impact is the return to the liver cells up to 100% of the total amount of acids produced by the liver entering the lumen of the small intestine.
An increase in the absorbability of this component leads to a decrease in the intensity of the synthesis of acids in hepatocytes and, as a consequence, to an increase in the amount of lipids in the blood plasma.
There is a circular dependence, as a result of which intestinal dysbiosis provokes a decrease in the intensity of biosynthesis of bile acids and their reduced entry into the lumen of the small intestine. That in turn leads to the aggravation of dysbiosis.
The occurrence of dysbacteriosis leads to the fact that cholesterol in the intestine is synthesized in a much smaller volume, provoking the development of violations of water-electrolyte, acid-base and energy balance. All of these pathological phenomena cause long-term and sustained disruption of the work of the digestive tract.
An insufficient amount of acid produced by the liver causes impaired absorption and digestion of incoming food.
In addition, there is a decrease in the sterilizing properties of bile, which creates favorable conditions for the introduction of helminths and a significant increase in pathogenic microbial communities. This situation leads to an increase in the number of negative flora and an increase in the degree of internal intoxication.
The occurrence of increased intoxication leads to an overuse of HDL.
An insufficient amount of HDL in the blood shifts the relationship between them and LDL in the direction of increasing the number of low-density lipoproteins, thereby causing the latter to precipitate as crystals in the sediment on the walls of the circulatory system.
The connection of helminthiasis and cholesterol levels
Strengthening the process of isolation of solid cholesterol on the inner walls of blood vessels is strongly promoted by unicellular parasites, which multiply rapidly in the intestine, in violation of the functions of digestion. The appearance in the human body of eggs and larvae of helminths that have settled in the intestine, leads to their migration through the vessels and lymphatic ducts.
Helminth eggs and larvae, which migrate vigorously through the vascular system, provoke damage to the walls, which leads to the precipitation of LDL cholesterol crystals in the sediment on the walls with the formation of cholesterol plaques.
Most often, the vessels of internal organs such as the liver, kidneys and lungs are subject to such damage.
Damage to the vascular system of the liver and kidneys causes a disturbance in the functioning of organs and leads to the development of diseases accompanied by the occurrence of failures in HDL synthesis. Insufficient flow of bile acids into the lumen of the colon causes a disorder of the conversion of cholesterol into steroid hormones and disrupts the flow of reactions that provide cholesterol utilization. These pathologies contribute to the occurrence of changes in intestinal motility, which leads to the suppression of antioxidant protection.
Such violations provoke an increased risk of developing cancer.
Intestinal microflora and cholesterol metabolism
Intestinal microflora consists of a whole complex of various microorganisms. The largest share among them is occupied by bifidobacteria and lactobacilli, as well as this group include Escherichia and enterococci.
Propionic acid bacteria are also permanent representatives of the normal intestinal microflora. These microorganisms, along with bifidobacteria, belong to the Corynebacterium group and have pronounced probiotic properties.
At present, studies have shown that these microorganisms are the most important link in ensuring cholesterol homeostasis and the development of such a pathology as hypercholesterolemia.
Normal gastrointestinal microflora interferes with the process of cholesterol absorption from the intestinal lumen. The excess of this component is transformed under the influence of bacteria and excreted from the body as part of the feces.
The presence of coprostanol in the fecal masses is currently regarded as a microbe-associated characteristic.
Intestinal microflora can not only destroy and bind cholesterol, but also synthesize it. The intensity of the synthesis depends on the degree of colonization of the gastrointestinal tract by microbial strains.
A change in the microecological conditions in the intestine is always accompanied by a change in the lipid composition in the blood plasma.
The relationship between cholesterol and intestinal activity is described in the video in this article.