Cholesterol, a fat-like substance, is the primary substrate of atherosclerotic plaque and the main culprit in the development of atherosclerosis – human arterial disease. A typical daily diet in which the fat content is physiological is about 500 mg of cholesterol (Skotland, Sandvig & Llorente, 2017). Cholesterol metabolism in the body depends on the type of fat consumed. Food sources of cholesterol contain eggs, butter, liver, kidneys, heart (Zhang & Liu, 2015). Products that block cholesterol are citrus, oat bran, legumes, carrots, pistachios, tea, bell peppers, eggplant.
Cholesterol alone is not harmful; blood must contain a certain amount of fat and cholesterol. The role of cholesterol in the human body is vast. It is part of cell membranes and also necessary for the synthesis of steroid hormones, and vitamin D. Cholesterol can come from food or be synthesized in the body itself. Normal serum cholesterol is 3.7–5.2 mmol / L (160–200 mg / dl) (Abuhammad, 2017, p. 2200). Seasonal fluctuations are characteristic of cholesterol levels; the highest level is determined in winter, the lowest – in summer. These differences are associated with changing dietary and lifestyle features depending on the time of year.
Excess cholesterol is dangerous when the level of it in the blood exceeds an absolute value; it, in the form of plaques, begins to be deposited on the walls of the arteries and narrows their lumen. If cholesterol falls below two mmol / L, the probability of death of the patient is high (Abuhammad, 2017, p. 2200). In young girls, exhausting themselves with diets, the monthly cycle ends, and their ability to further experience the joy of motherhood is at risk (Anagnostis et al., 2015). Therefore, the liver tirelessly synthesizes cholesterol for the needs of the body and sends it to all organs.
However, to assess the real risk of developing vascular diseases, knowledge of the general level of cholesterol in the blood is not enough. A person may have relatively high blood cholesterol, but there is minimal risk of coronary heart disease. Conversely, with a low cholesterol content, a reasonably high risk of developing coronary heart disease may be characteristic of a person (Skotland et al., 2017). This is explained by the fact that lipids and cholesterol, in particular, do not dissolve in the blood, but when combined with specific proteins – lipoproteins, they are transported through the arteries.
Lipoproteins are proteins that transport cholesterol and triglycerides in bound form. Lipids are widely used to obtain many types of fatty foods, determining the nutritional value and taste. A food source is fats that are derived from plant materials – heavy oils that are rich in unsaturated fatty acids. The fats of terrestrial animals contain saturated fatty acids and are called animal fats (Abuhammad, 2017). Fats of marine mammals and fish are distinguished into a particular group.
Of most significant interest to the doctor are high-density lipoproteins (HDL), low density (LDL), and very low-density lipoproteins (VLDL). HDL – small in size, contains a lot of protein, and therefore reliable. Penetrating the wall of the vessel, they capture cholesterol and carry it to the liver; HDL prevents the development of atherosclerosis. An average HDL level of more than 50 mg / dL in men and more than 60 mg / dL in women is considered normal (Zhang & Liu, 2015 p.257). People with this level of HDL have a low risk of developing atherosclerosis.
A high risk of developing atherosclerosis is observed with low HDL content: less than 35 mg/dl in men and less than 45 mg/dl in women (Zhang & Liu, 2015 p.257). LDL and VLDL are low in protein; they are large and loose. Penetrating the wall of the vessel, they “fall apart,” so it is impregnated with cholesterol and triglycerides. An increase in blood levels of LDL and VLDL leads to the early development of atherosclerosis (Anagnostis et al., 2015). Indirectly, the level of HDL can be judged by the atherogenic coefficient (KA). The smaller it is, the more HDL is in the blood.
If the patient has a violation of lipid metabolism, the doctor will recommend that they follow a special diet containing a reduced amount of animal fats, as well as easily digestible carbohydrates. The nutrition of such patients should include foods with high fiber content – vegetables and fruits, except potatoes, bananas, grapes. (Skotland et al., 2017). If following a diet, it is not possible to normalize cholesterol, and the doctor may additionally prescribe particular medications that lower it.
So, the normal functioning of several vital systems of the human body is impossible without cholesterol. Cholesterol is the building material for cell membranes in cell division. Not a single cell of the body can do without it since the “cholesterol framework” forms the basis of cell membranes, regulates their permeability and activity of membrane enzymes. The strength of the cell and the ability to survive to a certain extent depend on the amount of cholesterol in the membrane. Cholesterol is a precursor – the “raw material” for the synthesis of female sex hormones estrogen and progesterone, male sex hormone testosterone, and steroid hormones produced by the adrenal glands.
References
Abuhammad, A. (2017). Cholesterol metabolism: A potential therapeutic target in Mycobacteria. British Journal of Pharmacology, 174(14), 2194-2208.
Anagnostis, P., Stevenson, J. C., Crook, D., Johnston, D. G., & Godsland, I. F. (2015). Effects of menopause, gender, and age on lipids and high-density lipoprotein cholesterol subfractions. Maturitas, 81(1), 62-68.
Skotland, T., Sandvig, K., & Llorente, A. (2017). Lipids in exosomes: Current knowledge and the way forward. Progress in Lipid Research, 66, 30-41.
Zhang, J., & Liu, Q. (2015). Cholesterol metabolism and homeostasis in the brain. Protein & Cell, 6(4), 254-264.