MARCO TEÓRICO
2.2 BASES TEÓRICAS
2.2.1 El derecho a la vida
Early detection and early control of high cholesterol in a person is an important step in reducing the development and progression of coronary heart disease and atherosclerosis. Lowering plasma cholesterol by diet and drugs slows and may even reverse the progression of atherosclerotic lesions and the complications they cause
The demonstration that lipid-lowering therapy significantly reduces the clinical complications of ASCVD has brought the diagnosis and treatment of these disorders into the domain of the general internist. The metabolic consequences associated with changes in diet and lifestyle have increased the number of hyperlipidemic individuals who could benefit from lipid-lowering therapy.13 Most patients with hyperlipidaemia are asymptomatic and have no clinical signs. Many are discovered during the screening of high-risk individuals 11
Guidelines for the screening and management of lipid disorders have been provided by an expert Adult Treatment Panel (ATP) convened by the National Cholesterol Education Program (NCEP) of the National Heart Lung and Blood Institute.
The NCEP ATPIII guidelines published in 2001 recommend that all adults over age 20 have plasma levels of cholesterol, TG, LDL-C, and HDL-C measured after a 12-hr overnight fast.9
Selective screening of people at high risk of cardiovascular disease should be undertaken, to include those with:
A family history of coronary heart disease (especially below 50 years of age)
A family history of lipid disorders
The presence of a xanthoma
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The presence of xanthelasma or corneal arcus before the age of 40 years
Obesity
Diabetes mellitus
Hypertension
Acute pancreatitis
Those undergoing renal replacement therapy
Serum cholesterol concentration does not change significantly after a meal and as a screening test, a random blood sample is sufficient. If the total cholesterol concentration is raised, HDL cholesterol, TG, and LDL cholesterol concentrations should be quantitated on a fasting sample. If a test for hypertriglyceridaemia is needed, a fasting blood sample is mandatory 11
Multiple epidemiologic studies have demonstrated a strong relationship between serum cholesterol and CAD. Randomized controlled clinical trials have unequivocally documented that lowering plasma cholesterol reduces the risk of clinical events due to atherosclerosis. Since both hypertriglyceridemia and low plasma levels of HDL-C confer higher ASCVD risk, the NCEP ATPIII recommends more aggressive therapy to lower the plasma LDL-C in patients with these dyslipidemias.9
Hyperlipidaemia results from genetic predisposition interacting with an individual's diet.11 Studies show the role of the environment rather than the genetic make-up of a population. Data from The Multiple Risk Factor Intervention Trial (MRFIT) have shown that although cardiovascular risk rises progressively as total cholesterol concentration increases the risk increase is modest for individuals with no other
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cardiovascular risk factors. With each additional risk factor the effect produced by the same difference in cholesterol concentration becomes greatly magnified.11
Reference values 14,15
Normal values vary with age, diet, sex and geographic regime.
Recommended levels of lipoproteins in Indian population are : Total cholesterol : <200mg/dL
HDL cholesterol : >40mg/dL Triglycerides : <150mg/dL LDL cholesterol : <130mg/dL
TC/HDL Ratio : <3.0 indicates low risk,3.0-5.0 indicates high risk.
LDL/HDL Ratio : 1.5-3.5mg/dL
Nonpharmacologic Treatment11,13
Therapeutic Lifestyle Changes (TLC) includes a cholesterol-lowering diet (TLC diet), physical activity, and weight management for anyone whose LDL is above goal.
Dietary and life-style intervention
Studies have reported only modest cholesterol lowering benefits of diet therapy.
The effect of diet therapy varies among individuals. Some have striking reduction in LDL upto 25 – 30% whereas others will have clinically important increase. Moreover diets very low in total fat or in saturated fat may lower HDL as much as LDL. Low fat, high carbohydrate diet may result in reduction in HDL.
Still diet control is the cornerstone of therapy in the management of hyperlipidaemias. Modification of life-style, which includes food habits, cessation of
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smoking, cutting down alcoholic beverages, weight control and regular exercises, is not only necessary to attain eulipaemia but is the first step in the management of hyperlipidaemias.
Frequent snacks and canned or commercially available precooked food (junk food) should be abandoned as they are rich in fats and cream as well as refined carbohydrates.
Alcohol supplies empty calories; its intake should be restricted to social purposes
in a patient with dyslipidaemia and in others should not exceed 30 g/day . Dietary protein should be such that its fat content is low, viz., dried beans, peas
and pulses, chicken-breast, lean meat, low-fat dairy products and game birds and animals.
The diet should contain adequate amount of natural soluble fibres derived from oats and barley, certain fruits such as oranges apples,and pears and vegetables such as brussels sprouts and carrots.13,16
Substitution of saturated fat with monounsaturates and polyunsaturates
Most polyunsaturated fats come from vegetable oils, whereas most saturated fat comes from meat and dairy products. Monounsaturated oils, particularly olive oil, and polyunsaturated oils such as sunflower, safflower, corn and soya oil, should be used instead of saturated fat-rich alternatives. Hydrogenation increases saturation and adds trans FA which are as bad as saturated fat. Turkey breast and chicken breast are literally free of cholesterol as soon as the skin is removed.11,17
Reduce the dietary cholesterol intake. Liver, offal and fish roes should be avoided.
Although eggs and prawns are rich in cholesterol their total contribution to the body's cholesterol pool is small and they can still be part of a balanced lipid-lowering diet.11
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In the hypercholesterolemic patient, dietary saturated fat and cholesterol should be restricted. Dairy products and meat are the principal sources of saturated fat in the diet.
Fish and poultry with fat and skin removed should be substituted for this. Meat products including sausages and reconstituted meats should be avoided since the concentration of fat is unknown and often high. Baking and grilling of meats reduces the fat content and is preferred to frying. Do not add fat in the cooking and serving process. Low-fat or cottage cheese and skimmed or semi-skimmed milk should be substituted for the standard full-fat varieties. Pastries and cakes contain large quantities of fat and should be avoided.
Similarly, refined carbohydrates like maida and maida preparations should be avoided while carbohydrates with high-fibre content are preferred.11
Certain foods and dietary additives are associated with modest reductions in plasma cholesterol levels. Plant stanol and sterol interfere with cholesterol absorption from the intestine by competing for space in the micelles that deliver lipid to the mucosal cells of the gut. and reduce plasma LDL-C levels by 10 to 15% when taken three times per day. They are largely unabsorbed and excreted in the stool.9
For patients who are hypertriglyceridemic, the intake of simple sugars should also be curtailed. For severe hypertriglyceridemic restriction of total fat intake is critical.
The most widely used diet to lower the LDL-C level is the “Step 1 diet”
developed by the American Heart Association. Most patients have a relatively modest (10%) decrease in plasma levels of LDL-C on a step I diet in the absence of any associated weight loss. In this diet no more than 30% of total calorie is provided by fat and less than 10% of total calories is provided by saturated fat. Monounsaturated fats should contribute 10% to 15% and polyunsaturated fats should contribute 10% or less of
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the total daily energy intake. Cholesterol intake should be less than 300 mg/dl. Further reduction in fat intake is unacceptable to many patients. 9
Weight loss and exercise: The treatment of obesity, if present, can have a favorable impact on plasma lipid levels. Plasma TG and LDL levels tend to fall and HDL levels tend to increase in obese persons who lose weight. Aerobic exercise has a very modest elevating effect on plasma levels of HDLC. Gradual reduction protocols along with dietary restrictions have to be implemented to achieve an ideal bodyweight13
A reduced fat diet, which is more realistic, only affects those levels if accompanied by weight loss. Cutting fat without losing weight actually increase TG levels and decrease HDL.18 Eating more calories than body needs, whether from fat or carbohydrates, will be stored as fat. Hence the aim should be to lower total calorie intake than total fat intake.19
Eating small amounts of fat can keep from overindulging on total calories.
Dietary fat causes our bodies to produce a hormone that tells intestines to slow down the emptying process so that fullness is felt and are less likely to overeat.20 Moreover without some fat in the diets, body could not make nerve cells and hormones or absorb fat soluble vitamins. In any type of secondary hyperlipidaemia, the primary care envisages correction of the underlying cause which has induced hyperlipidaemia.
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Fig. 9:Diet pyramid 21 Natural sources reducing hyperlipidemia 18,20
Along with getting plenty of fiber, there are foods that will help in promoting the lowering of cholesterol as well as herbs that can further reduce cholesterol.
Carrots, apples and the white layer inside of citrus rinds containing pectin are advantageous to lowering cholesterol levels
Avocado, which is very high in fat, has unexpectedly become a cholesterol reducer Beans are high in fiber and low in cholesterol
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Garlic and onions in daily diet lower cholesterol and is also credited with lowering blood pressure.
Cayenne pepper (Capsicum minimum) and other plants that contain the phenolic compound capsaicin have a well demonstrated effect in lowering blood cholesterol levels, as does the widely used spice Fenugreek.
Caraway is another aromatic spice with demonstrable cholesterol lowering properties.
Strawberry reduces oxidative damage to LDL while mainaining reduction in blood lipids.
Soyaprotein decreases total cholesterol, LDL and Triglycerides
Green leafy vegetables, pulses, legumes, root vegetables, and unprocessed ereals, help reduce circulating lipid concentrations.
Olive oil contains polyunsaturated fats that help to lower LDL levels while increasing levels of HDL, or "good" cholesterol.
Nuts such as walnuts, almonds, hazelnuts and pistachios have polyunsaturated fatty acids prominently, which can reduce blood cholesterol levels.
Chinese red yeast rice (which contains lovastatin) can have modest cholesterol-lowering effects.
Polyphenolic substance derived from cocoa powder contribute to reduction in LDL and elevation in HDL and suppression of oxidized LDL and thereby reduces atherogenesis Peanut and peanut butter lowers cholesterol and reduces CHD risk
Flavonoid rich dark chocolate has beneficial effect on endothelial function Cinnamon has blood-thinning properties that can help lower cholesterol levels
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Marine fish oils containing long chain omega – 3 FA eicosapentaenoic acid ( EPA ) and docosahexaenoic acid ( DHA ) have potential role in reducing plasma levels of cholesterol and TG and thereby reducing incidence of CAD . Fatty fish, such as salmon, tuna and mackerel, is an excellent source of omega-3 FA, and the American Heart Association recommends getting at least two servings of fatty fish each week for cholesterol management and general heart health.
Flaxseed and canola oil also contain some omega-3 fatty acid
Fig. 10: Natural sources reducing hyperlipidemia 19,20,21,22
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