The first thought that comes to a person’s mind when buying something with high cholesterol level would be “NO! I don’t want to end my life with a heart attack!!” They are probably right but CAN THEY POSSIBLY LIVE WITH NO CHOLESTEROL AT ALL? Cholesterol is the cause of number of diseases related to heart but on the other side it is an essential sterol that gets converted to other steroid hormones. Not to mention that the cholesterol intake level of a person is proportional inversely to the cholesterol synthesized by the body itself. So is cholesterol really a nightmare or is this just another misconception?
Cholesterol is a lipid found in the tissues of all the animals, associated with other sterols. It is the best known member of the biological group – sterol, a combination of steroid and an alcohol. Most of the cholesterol is produced inside the body and only a minute quantity has dietary origin.
Almost of 20-25% of the total daily production occurs in the liver. The other sites include the intestines, suprarenal glands and reproductive organs. This cholesterol is either converted to other hormones, transported to cell that require cholesterol or secreted via bile into the intestines. Of the cholesterol poured into the intestines, 92-97% is reabsorbed in the intestines and recycled via the enterohepatic circulation. The cholesterol, insoluble in blood, of the diet is transported to the liver from the intestines, where it is absorbed, within the lipoproteins – chilomicrons, Very Low Density Proteins (VLDL), Intermediate Density Lipoproteins (IDL), Low Density Lipoprotein (LDL) & High Density Lipoproteins (HDL).
Cholesterol is mainly obtained from food having saturated fatty acids and is also synthesized from acetate inside the body. Normally the total amount of cholesterol from these two sources remains constant because the rate of cholesterol synthesis in the liver is under feedback control. When the dietary intake is high, liver synthesis is low; when intake is low, synthesis increases.
LDL is the major transport protein for cholesterol, supplying both free and esterified cholesterol to body tissues. High Density Lipoprotein (HDL) is involved in the transport of cholesterol to the liver to be broken down and excreted, and in removing some LDL cholesterol from artery walls. The esterified cholesterol is essential for a cell to maintain the fluidity of membrane over a wide range of temperature, so the cells use this esterified cholesterol for its maintenance. If the cholesterol is not esterified, the cells pushes it and the free cholesterol comes in the cholesterol, which sometimes along with Ca++ accumulates in the capillaries causing embolus formation and coronary obstruction.
The significance of cholesterol cannot be neglected. Some researched indicate that cholesterol might be used as an anti-oxidant. Besides that it also maintains the fluidity of the cell membranes. The cholesterol content of a membrane varies with the tissue and with specific membrane function. The ratio of cholesterol to polar lipids affects the stability, permeability, and protein mobility of a membrane. Membranes with high ratios have high stability and relatively low permeability; their major function is a protective barrier.
They serve primarily in synthetic and degradative reactions and energy production. It also reduces the permeability of hydrogen and sodium ions. In addition to its role in membrane structure cholesterol has other important functions. Cholesterol is stored in the adrenals, testes, and ovaries, chiefly as the fatty acid ester, and converted to steroid hormones. These hormones include the male and female sex hormones (androgens and estrogens) as well as the adrenal corticoids (cortisol, corticosterone, aldosterone, and others). In the liver cholesterol is the precursor of the bile acids, 24 steroid carboxylic acids that aid in the digestion of foods, especially lipids, and, when linked with the amino acids glycine or taurine, form the bile salts. Recently it has been suggested that cholesterol assists in the formation of lipid rafts in the membrane.
Besides the numerous functions of cholesterol, high free cholesterol level in the blood can cause life threatening problems as well. As mentioned above LDL is involved in the transportation of cholesterol. But high levels of LDL or free cholesterol in the blood causes the cholesterol to deposit in the blood capillaries hence narrowing the lumen of the vessels. The narrowed vessels increase the blood pressure and may lead to its rupture and ultimately causing an embolus. In the brain, it causes cerebro-vascular accidents and in heart it causes Ischemic Heart Disease. High LDL level are major cause for the arthrosclerosis of the arteries, leading to coronary heart disease and other forms of cardiovascular disease. However increase levels of HDL not only transport cholesterol to the liver to be broken down and excreted but also remove LDL cholesterol from the artery walls.
It has been suggested that abnormally low levels of cholesterol might cause depression, cancer and cerebral hemorrhage but it unclear whether cholesterol itself is responsible for it or something else associated with low levels of cholesterol. Esterified cholesterol when crystallizes in the gall bladder, is the major cause of formation of gall stones which leads to severe pain in near the liver region.
Cholesterol is present in many dietary components that we consume daily. This cholesterol is called the dietary cholesterol. Its percentage is significantly higher in animal fats (saturated fats), eggs, yolks, beef, poultry, liver, kidneys, and shrimps. Besides these, plants and fungi also contain trace amounts of cholesterol so even a vegetarian’s diet has cholesterol in it but in trace amounts.
Although the intake level of cholesterol must be kept low but not so low so as to lead to its deficiency which would the affect the normal anatomical and physiological state of the body. Since the total cholesterol level in the body almost always remains same so people with higher cholesterol intake maybe at the same risk of having a heart attack as those with lower cholesterol intake. An effective way to keep the cholesterol balance healthful and beneficial to the body is by exercising regularly whether walking, sprinting, or working out in the gym. With this, the benefits of cholesterol would dominate its harms and the body would function normally at its optimum performance.