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CHOLESTEROL TREATMENT | Learn more about Cholesterol What is cholesterol?Cholesterol is a member of the group of substances known as steroids and it is a versatile molecule with a number of important roles in the body. It is a major component of all cell membranes. The insulation material for nerve fibres, myelin, is rich in cholesterol, thus it is essential for the functioning of the nervous system. Cholesterol is also required for the formation of hormones such as oestro-gens and Cortisol and for other essential molecules such as vitamin D. Most of the body's cholesterol is synthesised by the liver, but small amounts are obtained from our diet. It is transported round the body in the blood. Some cholesterol is excreted by the liver as a component of bile — the bile salts. Bile salts are detergents and aid the digestion of fat in the intestine. A deficiency of bile salts in the intestine prevents complete absorption of fats. Cholesterol is the most common type of steroid in the body and a critically important molecule. Cholesterol is a fatty substance (a lipid) that is an important part of the outer lining (membrane) of cells in the body of animals. Cholesterol is also found in the blood circulation of humans. Cholesterol is carried in the bloodstream as lipoproteins. Low-density lipoprotein (LDL) cholesterol is the "bad" cholesterol, conversely, high-density lipoprotein (HDL) cholesterol is the "good" cholesterol. The cholesterol in a person's blood originates from two major sources; dietary intake and liver production. Dietary cholesterol comes mainly from meat, poultry, fish, and dairy products. Organ meats, such as liver, are especially high in cholesterol content, while foods of plant origin contain no cholesterol. After a meal, cholesterol is absorbed by the intestines into the blood circulation and is then packaged inside a protein coat. This cholesterol-protein coat complex is called a chylomicron. The liver is capable of removing cholesterol from the blood circulation as well as manufacturing cholesterol and secreting cholesterol into the blood circulation. After a meal, the liver removes chylomicrons from the blood circulation. In between meals, the liver manufactures and secretes cholesterol back into the blood circulation. Most Prescribed Medications [Sorted by Popularity]Statins®, Lipostatin®, Tricor®, Shuddha Guggulu®, Simvastatin®, Zocor®, Zetia®, Niacin®, Niacor®, Niaspan®, Slo-Niacin®, Red yeast rice [Monascus purpureus], Atorvastatin®, Lipitor®, Gemfibrozil®, Lasuna®, Lopid®, Pravastatin®, Pravachol®, Lovastatin®, Mevacor®, Crestor®, Altocor®, Vytorin® What are LDL and HDL Cholesterol [Hyperlipidemia]?LDL cholesterol is called "bad" cholesterol, because elevated levels of LDL cholesterol are associated with an increased risk of coronary heart disease. LDL lipoprotein deposits cholesterol on the artery walls, causing the formation of a hard, thick substance called cholesterol plaque. Over time, cholesterol plaque causes thickening of the artery walls and narrowing of the arteries, a process called atherosclerosis. Cholesterol levelsThe concentration of cholesterol in blood plasma in a newborn infant is usually below 2.5 mmol dm-3. This gradually increases to a maximum level in childhood of about 4.0 mmol dm-3. In Western societies cholesterol levels rise progressively during adult life to an average of 6.5 mmol dm-3. In some individuals it can increase to as much as 8.5 mmol dm-3. This rise does not occur in less affluent societies, in which the incidence of CHD is found to be much lower, strongly supporting a causal link. Research shows that the risk of CHD rises with the plasma cholesterol levels and that this rise is graded and continuous. Although blood cholesterol concentration is, to a certain extent, genetically determined, high plasma cholesterol levels are often the result of a poor diet — one rich in fat and low in fibre. Saturated fats are especially influential. These include butter and the lard that many chip shops use to fry potatoes. Raised cholesterol levels are the result of a number of different genes interacting with dietary factors. Medical scientists have also shown that being overweight increases an individual's likelihood of having elevated plasma concentrations of cholesterol. There are people who are particularly susceptible to raised cholesterol levels — those with genetic disorders — as we have seen above. Genetic factors, however, are relatively uncommon causes of elevated cholesterol in the population as a whole — about 50% of all adults in the UK have higher than 'ideal' cholesterol levels, but only one in 500 has FH. This clearly makes it especially important that, as individuals, we take as much care as possible to maintain a healthy diet (hard as it is to forsake the chips!) and to reduce our susceptibility by avoiding danger factors such as smoking. Population studies and clinical trials have shown that lowering blood cholesterol levels reduces the incidence of fatal and non-fatal coronary heart disease. For those who have elevated plasma cholesterol, drug preparations are available to help lower the level. Level of LDL cholesterol in the bloodDiets that are high in saturated fats and cholesterol raise the levels of LDL cholesterol in the blood. Fats are classified as saturated or unsaturated (according to their chemical structure). Saturated fats are derived primarily from meat and dairy products and can raise blood cholesterol levels. Some vegetable oils made from coconut, palm, and cocoa are also high in saturated fats. Therapeutic lifestyle changes to lower cholesterol -
Lowering LDL cholesterol involves losing excess weight, exercising regularly, and following a diet that is low in saturated fat and cholesterol. For more, please read the TLC, Therapeutic Lifestyle Changes article. Cholesterol-lowering drugsCholesterol-lowering drugs are expensive. Educating patients about how to keep their cholesterol level down, especially by modifying their diets, is much cheaper and better than drug treatment. However, it can be very difficult to put widespread lifestyle change into practice. Firstly, sufficient money and medical staff are needed to provide the health education. Secondly, the advice must reach all the people who need it. Thirdly, and probably most difficult of all, patients must have the motivation to stick to a healthy way of life. We all know that this is not always easy. If lifestyle changes do not work, or if an individual is at high risk (because of an inherited disorder), then drugs are required. The most effective cholesterol-lowering agents are the statins, originally isolated from fungi. These drugs work by inhibiting an enzyme that has a key role in cholesterol synthesis in the liver. As levels of cholesterol in the liver cells fall, the cells increase their uptake of cholesterol from the bloodstream via receptor proteins on the cell surface (proteins known as LDL receptors). This not only reduces the amount of circulating cholesterol but also means that the liver cells are stimulated to produce more LDL receptors. This mops up more LDL cholesterol and so increases the drug's effect. Normal cholesterol blood levelIn fact, there is no definite normal blood level for LDL cholesterol. In most other blood tests in medicine, normal ranges can be set by taking measurements from large number of healthy subjects. For example, normal fasting blood sugar levels can be established by performing blood tests among healthy subjects without diabetes mellitus. If a patient's fasting blood glucose falls within this normal range, he/she most likely does not have diabetes mellitus, whereas if the patient's fasting blood sugar tests higher than the normal range, he/she probably has diabetes mellitus and further tests can be performed to confirm the diagnosis. Medications, such as insulin or oral diabetes medications can be prescribed to lower abnormally high blood sugar levels. Unfortunately, the normal range of LDL cholesterol among healthy adults (adults with no known coronary heart disease) in the United States may be too high. The atherosclerosis process may be quietly progressing in many healthy adults with average LDL cholesterol blood levels, putting them at risk of developing coronary heart diseases in the future. What is Low HDL Cholesterol best treatment?In clinical trials involving lowering LDL cholesterol, scientists also studied the effect of HDL cholesterol on atherosclerosis and heart attack rates. They found that even small increases in HDL cholesterol could reduce the frequency of heart attacks. For each 1 mg/dl increase in HDL cholesterol, there is a 2 to 4% reduction in the risk of coronary heart disease. Although there are no formal NCEP (please see discussion above) target treatment levels of HDL cholesterol, an HDL level of <40 mg/dl is considered undesirable and measures should be taken to increase it. Raising HDL Cholesterol levelsRegular aerobic exercise, loss of excess weight (fat), and cessation of smoking cigarettes will increase HDL cholesterol levels. Regular alcohol consumption (such as one drink a day) will also raise HDL cholesterol. Because of other adverse health consequences of excessive alcohol consumption, alcohol is not recommended as a standard treatment for low HDL cholesterol. In fact, the very first step in increasing HDL cholesterol levels (and decreasing LDL/HDL ratios) is therapeutic life style changes. When these modifications are insufficient, medications are used. In prescribing medications or medication combinations, doctors have to take into account medication side effects as well as the presence or absence of other abnormalities in cholesterol profiles. Medications that are effective in increasing HDL cholesterol include nicotinic acid (niacin), gemfibrozil (Lopid), estrogen, and to a much lesser extent, the statin drugs (discussed below). A newer medicine, fenofibrate (Tricor) has shown much promise in selectively increasing HDL levels and reducing serum triglycerides. Food SourcesIn foods, cholesterol is found in eggs, dairy products, meat, and poultry. Egg yolks and organ meats (liver, kidney, sweetbread, and brain) are high in cholesterol. Fish generally contains less cholesterol than other meats, but some shellfish are high in cholesterol. Foods of plant origin (vegetables, fruits, grains, cereals, nuts, and seeds) contain no cholesterol. Fat content is not a good measure of cholesterol content. For example, liver and other organ meats are low in fat, but very high in cholesterol. Diet and CHDCountries with the lowest rates of CHD are those where the diet has a high proportion of carbohydrate and less fat. The calories in the diet come from the carbohydrates rather than from fat, whereas in countries with high rates of CHD the reverse is true. Also, in countries where the energy intake from fat is relatively high but the fat used is in the form of polyunsaturated fats or monounsaturated fats, such as olive oil, there is a lower rate of heart disease. Countries where government initiatives for changing population diet have been implemented successfully, e.g. in Scandinavia, have shown dramatic reductions in the incidence of CHD. New dietary therapiesSterols and stands, substances that occur naturally in plants, lower blood cholesterol by inhibiting the absorption of cholesterol in the intestine. Research has shown that using margarines containing sitostanol-ester can reduce serum cholesterol levels by 10-15% when used as part of a balanced diet. Sterols and stanols occur in almost all vegetables, particularly grains such as corn, wheat and rye. In principle, therefore, we could increase our intake simply by including enough of these foods in our diet. Unfortunately, sterols and stanols are contained in these plants at very low concentrations — too low for us to affect our cholesterol level. For this reason, scientists have worked to develop a product — an ester of plant stanol — that can be incorporated into a number of different foodstuffs. To date it has been included in vegetable fat spread and cream cheese-style spread. The ester does not alter the food's flavour but it is believed that the amount of cholesterol absorbed from a food containing it is only around 20%. This compares favourably with the 50% that our bodies absorb from a diet in which there is no plant stanol ester. The stanols have little in the way of side effects and so are suitable for use by large numbers of people. Because they can be incorporated into everyday food products they can then be used without altering people's normal eating habits. Foods containing plant stanol esters have recently arrived on the supermarket shelves in the UK. These include the spread Benecol. ATHEROSCLEROSISThe heart pumps blood around the body, supplying oxygen to all organs, including the heart itself. The vessels that carry blood to the heart muscle are called coronary arteries. These arteries can sometimes become partially blocked by deposits containing fat molecules known as lipids. Blood plasma contains four types of lipid: fatty acids, triglycerides, phospholipids and cholesterol. Lipids are insoluble in water and most biological fluids, so to be transported in the blood they must bind to protein, forming soluble molecules known as lipoproteins. Atherosclerosis, or 'hardening of the arteries', is the disease process that leads to coronary heart disease (CHD). It is thought to begin as a result of injury to the interior of the blood vessel wall, followed by an inflam¬matory response. The injury that starts this process may be mechanical, chemical, toxic, viral or immunological (e.g. high blood pressure, smoking, environmental pollutants). Scar tissue forms at the site of the injury, and large foamy cells containing cholesterol form fibrous plaques. Eventually this leads to a narrowing of the blood vessel. These lesions (scars) develop over several years, during which time the individual may be quite unaware that it is happening, as he or she may have no symptoms. This process can eventually lead to angina (chest pain). The decreased blood flow to the heart muscle, particularly during exercise, means that there is insufficient oxygen for the muscle and it is forced to respire anaerobically, which generates lactic acid. It is the build-up of lactic acid which causes the intense pain characteristic of angina. If the fatty plaques rupture and a clot forms, this can block the coronary artery completely, causing part of the heart muscle to be severely damaged by lack of oxygen. This is what we call a heart attack or myocardial infarction. Atherosclerosis can occur elsewhere in the body. If it affects the arteries supplying the brain, a stroke may result, while narrowing of the arteries in the legs can lead to tissue death and gangrene. Coronary heart disease (CHD)CHD is a major cause of illness and death in Western society, and is the largest single cause of premature death in the UK, responsible for 180 000 deaths annually. This horrifying statistic seems even more dreadful when we realise that it is equivalent to a jumbo jet load of people dying every single day! The three most important risk factors for the development of CHD are: hyperlipidaemia, high blood pressure and smoking. Hyperlipidaemia has a crucial role. Not only does it represent a risk factor in its own right but it multiplies the effects of the other risk factors several times over. Several different lipoproteins are responsible for the transport of cholesterol through our bodies. Two in particular are important in CHD — low-density lipoproteins (LDLs) and high-density lipoproteins (HDLs). Both carry cholesterol between the liver (where it is manufactured) and the sites in the body where it is used. Excess LDL cholesterol can infiltrate the walls of blood vessels. This can lead to the dangerous accumulation that increases the risk of CHD. High levels of LDL cholesterol are linked directly to the development of atherosclerosis and CHD — a fact that leads us to call cholesterol carried by LDLs 'bad' cholesterol. HDLs remove excess cholesterol from peripheral tissues, returning it to the liver to be broken down and then excreted. They could be viewed as arterial 'hoovers'. High levels of HDL cholesterol have a protective effect and so cholesterol transported by HDLs is called 'good' cholesterol. Familial hypercholesterolaemiaFamilial hypercholesterolaemia (FH) is an inherited condition, caused by a dominant gene. Individuals who are heterozygous (having only one copy of the dominant gene) have cholesterol levels of around 8 mmol dm-3, whereas those homozygous for the dominant gene (having two copies) can have cholesterol levels as high as 40 mmol dm-3. The ideal level is less than 5 mmol dm-3. In FH, high levels are present from birth and they continue to be high throughout the person's life. FH (heterozygous) is one of the most common genetic diseases in our society, affecting around one person in every 500 of the population (about 100 000 people in Britain alone). Untreated, up to 85% of men heterozygous for FH have a heart attack and 50% of these die before they reach the age of 60. Women heterozygous for FH develop coronary heart disease 10-15 years later than men. Sadly, people homozygous for FH can develop CHD and may even die as young as 20-40 years old. The measurement of cholesterolRapid methods for cholesterol analysis are now available and have been marketed aggressively. For example, there has been a recent 'know your number' campaign in the USA. A drop of blood from a finger-prick is spotted onto a 'dry' reagent strip and the cholesterol measured in a portable machine. Such tests are carried out by high-street chemists, health food shops and occasionally by roving cholesterol-testing vans parked outside supermarkets (no doubt with offers of low-fat products from within the store!). These methods are primarily for broad population screening and are not as reliable as those from rigidly quality-controlled tests performed in hospital laboratories. Counselling must also be given to assess the cholesterol level in terms of the individual's overall CHD risk and to avoid unnecessary anxiety. For proper risk assessment, a full lipid profile (i.e. total cholesterol, HDL, LDL and triglyceride measurement) needs to be performed while the subject is fasting. The full profile is essential when drug treatment is required. Such complex tests are only carried out in hospitals using sophisticated automatic analysers. Full details concerning the patient must be recorded as the results obtained can also be influenced by a number of factors including fasting state, posture, acute illness, pregnancy and menopause. FH can cause outward signs — 'lumps and bumps'. These are due to cholesterol being deposited deep within the knees, on the knuckles or in the tendons. Cholesterol may form deposits around the eyes or eyelids, with a yellow appearance. Another sign often seen in FH patients is a white ring around the outside of the iris, the coloured part of the eye. There are other inherited conditions that predispose to abnormal lipid levels; individuals with familial combined hyperlipidaemia have high levels of cholesterol and high levels of triglycerides. Guidelines for a Healthy Life and General RecommendationsMore than half of the adult population has blood cholesterol levels higher than the desirable range. High cholesterol levels often begin in childhood. Some children may be at higher risk due to a family history of high cholesterol.
In general, you want your total cholesterol to be less than 200 milligrams per deciliter (mg/dl), because that level carries the least risk of heart disease. When the level is above 200 mg/dl, the risk for heart disease increases. You should also know your levels of high density lipoprotein (HDL, also known as the "good cholesterol") and low density lipoprotein (LDL, or "bad cholesterol"). Talk to your health care provider about what your cholesterol levels mean. To lower high cholesterol levels: Cholesterol related topicsCholesterol, Heart Attack Pathology (Photo Essay), Heart Attack Prevention Overview, Heart Attack Prevention - Aspirin, Beta Blockers, ACE Inhibitors, Heart Attack Prevention - Omega-3 Fatty Acids, Heart Attack Prevention - Vitamins and Exercise. Cholesterol contents |
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