ABCs of “Cholesterol”

Cholesterol is the enemy for many of us living in this modern society. Many suffer from the chronic heart diseases and wants to come out of the ever increasing heart risks. Well, taking pills like Lipitor, Zocor, Pravachol, Zetia and Vytorin definitely reduce and control the cholesterol. However, that’s not the real solution. A wise decision would be to get educated about the Cholesterol and its ill effects. This does not imply that the cholesterol is bad. But, excess of cholesterol is bad for health and can increase the risk for heart diseases.

This writing gives you an overview of  cholesterol and why is this lipo protein required by the body. This writing is compilation of the information from different sources and a result of lot of research work. Hope this helps you in knowing and fighting cholesterol.

What & Why of  Cholesterol :

Cholesterol is a critically important compound in the human body. It is synthesized in the liver and then used in the manufacture of bile, hormones, and nerve tissue. Cholesterol is a type of lipid, one of the classes of chemical compounds essential to human health . Cholesterol makes up an important part of the membranes of each cell in the body. In addition, the liver uses cholesterol to make bile acids, which aid digestion. The body also uses cholesterol to produce vitamin D and certain hormones, including sex hormones.

The human body contains a feedback mechanism that keeps the serum concentration of cholesterol approximately constant. The liver itself manufactures about 600 mg of cholesterol a day, but that output changes depending on the intake of cholesterol in the daily diet. As a person consumes more cholesterol, the liver reduces it production of the compound. If one’s intake of cholesterol greatly exceeds the body’s needs, excess cholesterol may then precipitate out of blood and be deposited on arterial linings.

One of the major uses of cholesterol is the synthesis of bile acids. These are synthesized in the liver from cholesterol and are secreted in the bile. They are essential for the absorption of fat from the contents of the intestine. A clue to the importance of cholesterol is that most of the bile acids are not lost in the feces but are reabsorbed from the lower intestine and recycled to the liver. There is some loss, however, and to compensate for this and to meet other needs, the liver synthesizes some 1500–2000 mg of new cholesterol each day. It synthesizes cholesterol from the products of fat metabolism.

Large concentrations of cholesterol are found in the brain, spinal cord, and liver. Gallstones that occur in the gall bladder are largely made up of cholesterol. It is also found in bile (a fluid secreted by the liver), from which it gets its name: chol (Greek for “bile”) plus stereos (Greek for “solid”).

Normally, cholesterol produced by the liver circulates in the blood and is taken up by the body’s cells for their needs. Cholesterol can also be removed from the blood by the liver and secreted in bile into the small intestine. From the intestine, cholesterol is released back into the bloodstream.The body does not need cholesterol from dietary sources because the liver makes cholesterol from other nutrients.

Cholesterol and Triglycerides :

Cholesterol and triglycerides, another lipid, are two of the major fatty substances in the blood. Triglycerides may be used by cells for energy, or they may be stored for later use. Doctors often measure the amount of cholesterol and triglycerides in blood to help determine a patient’s overall health. High levels of cholesterol, particularly if accompanied by high levels of triglycerides, increase the risk of heart disease. Both cholesterol and triglycerides are carried through the bloodstream in large molecules called lipoproteins.

“Good” cholesterol and “Bad” cholesterol

Cholesterol is carried in the blood bound to protein molecules called lipoproteins. Most of the cholesterol is transported on low-density lipoproteins (LDLs). LDL receptors on body cell membranes help regulate the blood cholesterol level by binding with LDLs, which are then taken up by the cells. However, if there are more LDLs than LDL receptors, the excess LDLs, or “bad” cholesterol, can be deposited in the lining of the arteries. High-density lipoproteins (HDLs), or “good” cholesterol, are thought to help protect against damage to the artery walls by carrying excess LDL back to the liver.

High levels of LDL-cholesterol in blood are a primary cause of heart attacks. LDL can be found in the wall of heart arteries. Low levels of HDL-cholesterol also increase the risk of heart attack. Some scientists believe that HDLs help remove cholesterol from tissues.

Though high total and LDL cholesterol levels, along with low HDL cholesterol, can increase heart disease risk, they are among several other risk factors. These include cigarette smoking, high blood pressure, diabetes, obesity, and physical inactivity. If any of these is present in addition to high blood cholesterol, the risk of heart disease is even greater.

Factors affecting blood cholesterol levels:

• Heredity–High cholesterol often runs in families. Even though specific genetic causes have been identified in only a minority of cases, genes still play a role in influencing blood cholesterol levels.
• Weight–Excess weight tends to increase blood cholesterol levels. Losing weight may help lower levels.
• Exercise–Regular physical activity may not only lower LDL cholesterol, but it may increase levels of desirable HDL.
• Age and gender–Before menopause, women tend to have total cholesterol levels lower than men at the same age. Cholesterol levels naturally rise as men and women age. Menopause is often associated with increases in LDL cholesterol in women.
• Stress–Studies have not shown stress to be directly linked to cholesterol levels. But experts say that because people sometimes eat fatty foods to console themselves when under stress, this can cause higher blood cholesterol.

People also may have high cholesterol levels if they have an abnormal gene and this disorder is called familial hypercholesterolemia. Other factors that can cause high blood cholesterol include a malfunctioning thyroid gland, kidney disease, diabetes, and the use of various medicines, including certain diuretics.

Lipid Profile Tests:

The lipid profile is a group of tests that are often ordered together to determine risk of coronary heart disease. The tests that make up a lipid profile are tests that have been shown to be good indicators of whether someone is likely to have a heart attack or stroke caused by blockage of blood vessels (hardening of the arteries). The lipid profile includes total cholesterol, HDL-cholesterol (often called good cholesterol), LDL-cholesterol (often called bad cholesterol), and triglycerides.

The table shows the range of typical values as well as the values above (or below) which the subject may be at increased risk of developing atherosclerosis.

LIPID	Typical values (mg/dl)	Desirable (mg/dl)
Cholesterol (total)	170–210	<200
LDL cholesterol	60–140	<130
HDL cholesterol	35–85	>40
Triglycerides	40–150	<13

Note 1 : Total Cholesterol = HDL Cholesterol + LDL Cholesterol + 20% of Triglycerides

Note 2 : Cardiac Risk Ratio = Total Cholesterol / HDL Cholesterol. A cardiac risk ratio greater than 7 is considered a warning (you are encouraged to calculate the risk ratio with the latest lipid profile results)

Conditions Caused by High Cholesterol

High levels of cholesterol can cause a condition known as atherosclerosis, or the hardening of the arteries. When the arteries become filled with plaque, the walls become stiff and brittle. This not only restricts blood flow, but it can also cause the arteries to burst because they are so brittle; this can lead to blood clots.

But sometimes diet and exercise alone are not enough to reduce cholesterol to goal levels. Perhaps a one is genetically predisposed to high blood cholesterol. In these cases, doctors often prescribe drugs. The most prominent cholesterol drugs are in the statin family, an array of powerful treatments that includes Mevacor (lovastatin), Lescol (fluvastatin), Pravachol (pravastatin), Zocor (simvastatin), Baycol (cervastatin), and Lipitor (atorvastatin). Lipitor is the most popular drug ever sold ever in the history of the world. Lipitor does more than $9 billion in sales per year – that’s more than one million dollars per hour, every hour of every day, 365 days per year.

Summary :

Cholesterol is a type of lipid, one of the classes of chemical compounds essential to human health. Cholesterol and triglycerides, another lipid, are two of the major fatty substances in the blood. High-density lipoproteins (HDLs), or “good” cholesterol, are thought to help protect against damage to the artery walls by carrying excess LDL back to the liver. High levels of LDL-cholesterol in blood are a primary cause of heart attacks. LDL can be found in the wall of heart arteries.

Large concentrations of cholesterol are found in the brain, spinal cord, and liver. Gallstones that occur in the gall bladder are largely made up of cholesterol. It is also found in bile (a fluid secreted by the liver), from which it gets its name: chol (Greek for “bile”) plus stereos (Greek for “solid”).