HDL cholesterol: Protecting your heart and arteries Whats your cholesterol? As men reach middle age, theyre more likely to ask each other about health than sports, and when the talk turns from league leaders to medicine, cholesterol is likely to be in first place. Yet for all its notoriety, cholesterol is often misunderstood, especially when it comes to HDL, the good cholesterol. Its a shame, particularly since so many men overlook the simple things they can do to boost their levels of HDL cholesterol. Good, bad, and neutral Misconceptions about cholesterol begin with the very nature of the chemical. Most people think of it as a fat, but itsactually a sterol, a waxy, fatlike substance with a ringed structure not found in true fats. Another error is to think of cholesterol strictly as a health hazard. In fact, cholesterol is essential for good health. It is the building block of cortisol and all other steroid hormones. Without cholesterol, men wouldnt have testosterone, nor would women have estrogens. The third common mistake is to assume that the cholesterol in your blood comes from the cholesterol in your food. In fact, about two-thirds of the cholesterol in your blood is made right in your body by your liver. Dietary cholesterol does contribute to the remaining third but some dietary fats have an even greater role, since they prod the liver to produce more cholesterol, which then pours into the blood. The final misconception is that some cholesterol is good while some is bad. In fact, there is only one type of cholesterol; the cholesterol in an egg yolk has exactly thesame structure as the cholesterol that your body incorporates into your brain cells, turns into testosterone, or packs into an artery-blocking plaque. Like many misconceptions, however, this one begins with a very important truth. Instead of floating free in your blood, cholesterol latches onto blood proteins, which carry it through your body. Scientists separate these lipoproteins by spinning blood plasma in an ultracentrifuge. The lighter ones float to the top and are called low-density lipoproteins (LDLs); the heavier ones sink to the bottom and are called high-density lipoproteins (HDLs). The nature of a specific lipoprotein determines the fate of the cholesterol in your blood. LDLs deposit their load of cholesterol just where it will do the most harm, in the walls of arteries. That makes it the bad cholesterol. But where a villain lurks, a hero can be found. In this case its HDL, which snatches cholesterol away from artery walls. HDLcholesterol is very good indeed thanks to the HDL, not the cholesterol. HDL: Up close and personal In practical terms, the bottom line is simple: The higher your HDL cholesterol, the better. But in biologic terms, its a good deal more complex, and research into the molecular biology of HDL is on the verge of generating new therapies. HDL is a busy little world of its own. Each particle is composed of a group of proteins that are produced in the liver and intestines. In a typical HDL particle, about 70% of the protein is called apo AI, about 20% is apo AII, and at least seven other proteins contribute to the final 10%. But some HDL particles have different mixes of proteins. Various HDL subtypes also have different properties, but studies disagree about which types are most protective. As a result, clinicians are wise to measure total HDL levels without fretting about subtypes. Like all proteins,the production of HDLs proteins is directed by genes. Some men are lucky enough to inherit genes that direct a high production of HDL, while others are dealt a less favorable hand. Still, genes are only part of the story, since lifestyle factors and, to a smaller extent, medications have a powerful effect on HDL levels. In some men, though, balky genes limit their ability to boost HDL levels with exercise and other interventions. How HDL helps HDL enters the blood on its own, but it soon picks up cholesterol to become HDL cholesterol. Thats when it begins to fend off heart attacks and strokes. At first, scientists believed that HDL was simply a garbage collector that picked up cholesterol from an arterys walls and delivered it to the liver for disposal. Thats still considered the main role of HDL, but as researchers have unraveled the many steps that lead to arterial blockages, they have also accumulated evidence thatHDL can help in many ways: Reverse cholesterol transport. Its the updated take on the garbage man hypothesis. The first step in atherosclerosis occurs when LDL cholesterol lodges in the wall of an artery (see figure). If enough HDL is available, it will latch onto the cholesterol in the artery wall, lug it back into the bloodstream, and carry it to the liver. Since cholesterol is taken out of arterial cells, the process is sometimes known as cholesterol efflux. Since cholesterol is returned to the liver (where it was assembled in the first place), reverse transport is another name for the process. By either name, its good for vascular health, since the liver collects cholesterol from the HDL particles, packages it into bile salts and bile acids, and dumps it into the intestines for excretion in the feces. HDL in action Antioxidant activity. The next step in atherosclerosis occurs when the LDL cholesterol inthe artery wall is bombarded by oxygen free radicals that turn it into oxidized LDL cholesterol. Oxidized cholesterol is the stuff thats actually responsible for arterial damage and research shows that HDL has antioxidant activity that can help protect LDL cholesterol from free radicals. Anti-inflammatory action. An atherosclerotic plaque is not simply a mechanical build-up of cholesterol but a site of intense inflammation triggered by oxidized cholesterol and perpetuated by white blood cells called T lymphocytes and macrophages. Elevated levels of C-reactive protein (CRP) reflect the inflammation. HDL helps to quiet the inflammation, and it may also neutralize CRPs tendency to perpetuate the inflammatory cycle. Plaque stabilization. As the cholesterol-laden inflammatory plaque enlarges, it may fill an artery enough to cause angina. If the plaque develops a fibrous cap that holds it together, things dont get any worse. But if an unstable plaqueruptures, it can trigger a heart attack or stroke. Although the evidence that HDL can help stabilize plaques is less compelling than the data supporting its other benefits, research suggests HDL may help prevent plaque rupture. Antithrombotic activity. Plaque rupture is dangerous because it triggers the formation of an artery-blocking blood clot, or thrombus. By halting the flow of oxygen-rich blood, the clot kills heart muscle cells (heart attack) or brain cells (stroke). HDL reduces clot formation and accelerates the healing process that dissolves clots. Endothelial function. Even without advanced blockages, the arteries of patients with atherosclerosis are damaged goods. In particular, the endothelial cells that line the arteries inner surface fail to produce normal amounts of nitric oxide (NO), the tiny chemical that allows arteries to dilate (widen) when tissues need more oxygen. HDL helps preserve nitric oxide production and protectendothelial function. With all these activities, HDL cholesterol sounds as though it deserves the nickname good. But laboratory and clinical experiments dont tell the whole story. Does HDL actually reduce the risk of human cardiovascular disease? How much does HDL help? The Framingham Heart Study was responsible for many landmark discoveries about HDL cholesterol. Harvard researchers are rarely credited with making things simpler, but thats just what happened in the early days of HDL research, when the Physicians Health Study confirmed that HDL was protective and reported that various HDL subtypes are all helpful. Doctors have learned a lot about HDL since then, and the data show that the good cholesterol is very good indeed. Heart disease. Low HDL levels are associated with an increased risk of heart attacks, while high levels are protective. The protective value of high HDL levels is evidentat all LDL (bad) cholesterol levels, from very low to very high. According to the Framingham Heart Study, cardiac risk rises sharply as HDL cholesterol levels fall below 40 milligrams per deciliter (mg/dL). Low HDL cholesterol levels are particularly hazardous when triglyceride levels are high or other cardiac risk factors are present. But raising HDL levels does help. In general, each 1 mg/dL rise in an HDL cholesterol level can be expected to cut cardiac risk by 2% to 3%. Stroke. Strokes come in many forms, but the most common type, ischemic stroke, shares many risk factors with heart attack. High HDL cholesterol levels reduce the risk of stroke; in several studies, HDL cholesterol is a much better predictor of risk than LDL cholesterol, particularly in people older than 75. Erectile dysfunction (ED). Normal erections depend on many things, including healthy arteries that produce good amounts of nitric oxide. Its no surprise, then, that theMassachusetts Male Aging Study found that 16% of men with low levels of HDL cholesterol had ED, but none of the men with the highest levels had the problem. Longevity. Several investigations suggest that high HDL levels are linked to longevity, particularly exceptional longevity. Other research links high levels of HDL cholesterol to preserved cognitive function in old age. More research is needed to learn if HDL deserves the credit or if other genetic factors are responsible. But if HDLs role is confirmed, it may someday be known as the great cholesterol. Your goal There is no normal level for HDL cholesterol. The higher your level, the better. Still, targets are important. The National Cholesterol Education Program (NCEP) and the American Diabetes Association advise men to aim for HDL levels of at least 40 mg/dL. According to the third National Health and Nutrition Examination Survey, over 35% ofAmerican men do not meet this goal. And a great many more fail to meet the NCEPs more protective goal of 60 mg/dL or higher. Another way to determine your target is to take your bad cholesterol into account by calculating your cholesterol risk ratio. The math is easy: Just divide your total cholesterol by your HDL cholesterol: TC (mg/dL) / HDL (mg/dL) = Risk ratio The lower your ratio, the better. A ratio of 4.5 indicates average risk; the lower you go below that, the lower your risk but the higher you go, the higher your risk. Most doctors advise reducing the risk ratio by lowering LDL cholesterol levels, and many do that by prescribing a statin drug. It does work well but since statins reduce cardiac risk by roughly 40%, it doesnt work well enough for many men. Boosting HDL levels is one of the ways to get better results, but its often overlooked because its easier to lower LDL cholesterol than to raise HDLcholesterol. Hard or not, it can be done. © Group [EMAIL PROTECTED] [EMAIL PROTECTED]@yahoogroups.comWelcome To dimpill's gang! This is the Best Place to Hang around.We Give u the Best in Latest News, Jokes, Funny Pictures,Wallpapers,Latest Buzz and Much More! Connect your World with Us join Now http://groups.yahoo.com/group/dimpill_gang/join Affiliated group from dimpill_gang for Only Adult Mails http://groups.yahoo.com/group/fantazies/joinAffiliated group from dimpill_gang for Only Health and Food Mails http://groups.yahoo.com/group/Health_and_Gourmet/join
_______________________________________________ No banners. No pop-ups. No kidding. Make My Way your home on the Web - http://www.myway.com
