CHOLESTEROL, FATS & HEART DISEASE

Compiled by Dr.D.V.L. Rewal, Rtd. Regional Controller of Safety, Ordnance Factory Board.

CHOLESTEROL (C27H46O)

What is Cholesterol and why do we have it? Cholesterol is a white crystalline solid which is optically active. Its m.p. 149oC. It is odourless. This is the sterol of the higher animals, occurring free or as fatty esters in an animal cells, particularly in the brain and spinal cord. Cholesterol was first isolated from human gall-stones. The main source of cholesterol are the fish-liver oils and the brain and spinal-cord of cattle. Lanoline, the fat from wool, is a mixture of cholesteryl palmitate, stearate and oleate. It does not dissolve in water. Cholesterol has many beneficial functions. It is a necessary ingredient of the cell-walls of all animals, including human beings. It makes our skin water-proof and slows-down water-loss by evaporation from our bodies. It acts as an insulator in the myelin sheath that surrounds nerves and allows normal transmission of nerve impulses. Cholesterol is transported in the blood-stream along with fats. It is in this capacity that cholesterol becomes implicated in heart disease. Cholesterol is the chief constituent of hormones specially sex hormones. Cholesterol in the blood comes from two sources. (i) From foods we eat. (The amount of saturated fat in foods is a more important factor in raising blood cholesterol levels. (ii) Produced in liver and intestines.

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Cholesterol comes in foods from animal-origin. Even if we consume no cholesterol at all (i.e. if we are strict vegetarians, our body would manufacture enough cholesterol for proper growth and development). However, consumption of too much cholesterol can over-load our system and end-up in arterial system viz. coronary, cerebral etc. The Heart : Heart is a muscle that pumps blood through-out the body of an animal (including human beings) to deliver nutrients to all body cells and to remove waste-materials. Even while we sleep the heart beats 70 to 80 times per minute and pumps 1800 gallons of blood each day (during 1 lakh beats). Heart can increase its out-put nearly 5 fold. Heart muscles need a constant supply of nutrient-rich, oxygenated blood. This is supplied by coronary arteries that branch off from the aorta The cause of Coronary Heart Disease : (Atherosclerosis) It is the clogging of the coronary arteries with fatty, fibrous, cholesterolladen deposits called atheromata or plaques. These deposits thicken the artery walls, thus narrowing the channel through which the blood flows. Plaques are caused by an excess of cholesterol in the blood. How does the process start? When the food contains high amounts of saturated fats, plaques start developing right in child-hood. The plaque formation continues depositing during first 30-40 years resulting in decreasing the openings of the arteries. When the artery feeding blood to heart muscles gets blocked to the extent of 75 percent, the inevitable occurs. Angina : if one is lucky he feels the Angina Pectoris i.e. the mildest and earliest symptom of brief chest-pain, usually experienced on exertion. This pain occurs when enough quantity of blood cannot get through the blocked arteries to supply oxygen to the heart musclecells. Cells-deprived of oxygen for only a few minutes can recover, if we rest, thereby reducing the demand on the heart. If the oxygen supply is cut-off for longer periods, permanent damage to the heart may result. If one is not so lucky, a small blood-clot may become lodged in the narrowed artery and completely block the flow of blood to a particular portion of heart. This part of heart-muscle dies. Result : Heart Attack or Sudden Death. Nutrients The Role of Fats : There are 5 major classes of nutrients in our diet i.e. Proteins, Carbohydrates, Fats, Minerals and Vitamins. Fats occur in foods and in our body as triglycerides. These are transported in blood, which consists mainly of water. Enzymes, which function in a water medium, break them down and release energy.

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These fats are immiscible in water. So fats are packaged into particles to keep them separating out from the water in the blood. These particles, which also contain proteins and cholesterol, are called lipo-proteins (lipo means fat). There are three major types lipo-proteins:(1) VLDL (Very Low Density Lipoproteins) : The liver uses excess carbohydrates and fats from the blood, we eat to make triglycerides (fats). These triglycerides are packaged into VLDL for distribution from the liver to the rest of the body. VLDL particles contain large amounts of triglycerides and lesser amounts of cholesterol, protein and other fats. These VLDL particles are produced and released in large quantities, in blood after the meals. (2) LDL Lipo-Proteins (Low Density Lipo-Proteins) (The Bad Cholesterol) : As the VLDL particles circulate through the blood stream, triglycerides are removed from the particles and they enter the cells these are used as a source of energy. The fat-depleted VLDL particles are called LDL Low-Density Lipids. These are constituted by cholesterol and proteins. LDL particles remain in the blood-stream for different periods of time in different people. The longer the period, the more is the probability that a part of the cholesterol will be added up to the plaque that is building up in coronary artery walls. Thus, the higher the LDL level in the blood, the more cholesterol is available to clog the coronary arteries and the higher is the risk of developing atherosclerosis and coronary heart-disease. In some fortunate people, LDL particles are quickly removed from the bloodstream by special LDL receptors on cell-surfaces. Once inside the cells, cholesterol from the LDL is broken down. So their blood count shows that LDL is very low. For other people, LDL particles remain in the blood stream longer, producing higher LDL level in the blood. Since these particles are so rich in cholesterol, a high LDL Level results in high blood cholesterol level. (3) HDL Lipo-Proteins (The Good Cholesterol) : The High Density Lipo-Protein particles are the smallest of the lipo-protein particles. HDL removes cholesterol from LDL particles and cells and transports it to the liver. Here most of the cholesterol is broken-down into bile-acids and excreted into the small intestines. A part of the cholesterol is reprocessed into VLDL particles. By removing cholesterol from LDL, HDL prevents cholesterol from accumulating in the coronary arteries and thus protects against the development of heart-disease. The Higher the HDL level the more cholesterol is removed from the blood stream and lower the risk of heart attack. Total Blood Cholesterol Level = Sum of Cholesterol in VLDL + LDL + HDL -3-

VLDL is not measured directly, it is calculated from triglyceride level (which is measured only after a 12 hour fast). VLDL = Triglycerides 5 To sum-up : Lipoproteins and Risk of Heart Disease : LipoProtein 1. VLDL (Triglycerides) Risk increases if High Actions which help in reducing the risk (i) Restrict Alcohol. (ii) Exercise Regularly. (iii) Lose weight if over-weight. (iv) Eat less simple sugar (sweets). (v) Reduce saturated fat consumption. (i) Reduce saturated fat consumption. (ii) Reduce consumption of cholesterol. (i) Exercise Regularly. (ii) Stop Smoking (iii) Lose weight if over-weight.

2. LDL 3. HDL

High Low

The table above indicates some of the ways to lower our risks, change in life-style and by changing the foods we eat. It is seen from studies conducted on volunteers in U.S.A. that LDL cholesterol level decrease when saturated fat and cholesterol level in food-intake is decreased and when dietary poly-unsaturated fat is increased. Removing saturated fat from diet has two-times the blood-cholesterol lowering impact as does adding equal amount of polyunsaturated fat. Reduction of up to 33 percent in blood cholesterol level can be achieved by diet alone. Reducing blood cholesterol level lowers the risk of fatal and non-fatal heart attack.

National Institute of Health U.S.As recommendation Age 20 + Blood Cholesterol Levels (mg/dl.) Recommended Border Line Under 200 200 - 239 High Risk 240 +

Keep the Blood Cholesterol below 200 mg/dl. By diet (and drugs, if necessary). For reduction in Blood Cholesterol below 200 mg/dl., diet control is the first line of treatment. It should be given a fair and rigorous trial for at

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least 6 months before even considering drugs. Most adults can control their blood cholesterol below 200 mg/dl. by diet alone. The presence of coronary heart disease or other risk factors for heart disease such as male-sex ; family history of premature heart attach (before 55 years age) : Cigarette-smoking ; high-blood pressure, low HDL (below 35 mg/dl.) ; diabetes, cerebrovascular or peripheral vascular disease and severe obesity (30 percent or more over-weight) indicate the need for vigorous therapy.

BYPASS PATIENTS TAKE CARE : Bypass surgery may eliminate the symptoms of heart disease such as angina : but they do not cure the underlying atherosclerotic process : which goes on depositing fat in the coronary arteries. Bypass artery grafts have been found to accumulate plaque at a faster rate when the blood cholesterol level is high. It is common for such grafts to close completely in 5 years time. This need not happen. One can slow or even reverse the clogging of by-pass artery graft by changing what you eat and what you drink, thereby lowering the blood cholesterol level. Today a blood-cholesterol level of 230-240 mg/dl is understood to be a prime factor in the development of heart-disease. Saturated Fat : 5 kinds of vegetable fats are saturated : Coconut Oil, Palm Oil, Palm Keanel Oil, Cocoa-butter (in chocolate) and hydrogenated vegetable oil (DALDA). In general, animal fats are high in saturated fats and plant fats are low. SATURATED FAT RAISES LDL-CHOLESTEROL AND TOTAL BLOOD CHOLESTEROL LEVELS. CHEMICAL STRUCTURE OF THE FATS : Triglycerides are composed of three fatty acids attached to a glycerol molecule. In saturated fats, there is no double bond. In mono-unsaturated Fat structure there is one double bond. In Poly-unsaturated Fat there are Two or more double bonds.

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O CH2 O C CH2 (CH2) 15 CH3 Saturated (NO DOUBLE BOND) O CH - O - C CH2 (CH2)6 CH = CH (CH2)6 CH3 Mono-unsaturated (ONE-DOUBLE BOND) O CH2 O C CH2 (CH2)6 CH = CH CH2 CH2 CH = CH-(CH2)4 - CH3 Poly unsaturated (TWO OR MORE DOUBLE BONDS) Glycerol Fatty Acids portion

Mono Un-saturated Fat : Such fat has one point of un-saturation that is there is onedouble bond or 2 hydrogen atoms less in a molecule than in a saturated fat. Example : Olive Oil. Such fats lower LDL cholesterol without lowering HDL cholesterol. Poly-un-saturated Fat : These fats have two or more points of un-saturation or double bonds. i.e. 4 or more atoms of hydrogen less as compared to a saturated fat per molecule. These are liquids at room temperature. In general, vegetable oils, except coconut and palm oils are high in poly un-saturated fat. They lower blood LDL - cholesterol levels and to a much less extent HDL cholesterol levels. Dietary Cholesterol : Dietary cholesterol raises LDL cholesterol is found only in animal products, such as beef, pork, poultry, fish, cheese and other whole milk dairy products and eggs. Especially rich sources of cholesterol are egg yolks and organ-meats such as liver, pancreas and brain. Cholesterol is not found in foods made from plants, such as vegetables, fruits, nuts or seeds. Focus on Saturated Fat : Saturated fat is the most potent determinant of blood-cholesterol levels. It is twice as effective in raising blood-cholesterol as poly-unsaturated fat is lowering it. Fats have 9 cal/gm whereas proteins and carbohydrates contain only 4 cal/gm. FATS MAKE US FAT.

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Fats have been implicated as a risk factor in developing certain cancers such as breast and colon cancers.

It is necessary to focus on saturated fats because : (1) Saturated fats and cholesterol usually occur together in the same foods. So by avoiding foods high in saturated fat, we are also avoiding foods high in cholesterol. The exceptions are : (i) Egg Yolks and Organ Meats (brain, kidneys, liver and pancreas) are high in cholesterol but have only moderate amounts of saturated fat. (ii) Coconut oil, Palm Kernel oil, Cocoa Butter (in chocolate) and hydrogenated oils (the so called Daldas) are very high in saturated fat but have no cholesterol. (2) The cholesterol we eat, has much less effect on raising cholesterol levels, than does saturated fat. Contrary to popular belief, the amount of fats, especially saturated fat that we eat has a much greater effect on our blood cholesterol level than does the amount of cholesterol consumed by us. However, cholesterol intake should not be more than 300 mg. daily. (3) Keeping track of saturated fat makes a simple yet effective plan to follow for lowering blood-cholesterol level. How to reduce Saturated Fat Intake? (1) Substitute Full cream curds by low-fat curds. Instead of foods rich in saturated fat start using foods high in complex carbohydrates (starches) and fiber (such as rice, whole-grain, pastas, bread & cereals, vegetables and fruits). (2) Substitute foods high in saturated fat (such as butter, lard & beef tallow) by Polyunsaturated fats (such as margarine and vegetable oils other than coconut or palm oil). Let us make sure that Poly-unsaturated fat does not contribute more than 10% of total calories. As we remove saturated fat from our diet, we will have to replace it with something else say with complex carbohydrates i.e. whole-grain breads and pastas, fruits and vegetables. Enriching our diet with these foods has the additional advantage of increasing the intake of vitamins, minerals and fibers. Potato does not make us fat. It is what we do to it. A medium baked potato has 105 calories. We put 3 tablespoons of sour-cream (26 calories per tablespoon) on top and the innocent potato becomes 183 calories. When converted into crisp potato-chips it is around 400 calories.

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Similarly, a piece of bread has 80 calories per slice. When we add butter @ 100 calories per tablespoon, it becomes 180 calories per slice. It is the large amount of fat in the diet that leads to over-weight and obesity. Useful Tips : Use of Indian Vegetables and replacement of saturated fats with complex carbohydrates, and chicken with green beans expand the food-palate as well as taste-palate. Try eating relatively larger breakfasts and lighter dinners. Make all your meals low-fat. Avoid heavy dinner i.e. saving most calories at the end of the day, when we are least active.

Snacks : Micro-wave pop-corn is a great snack known to man-kind. It is a filling without fattening (unless it is drenched in butter or margarine). Nuts as snacks. The ones with least amount of saturated fat are Walnuts, Pecans, Almonds, Pistachios and hazelnuts (about 13-17 saturated fat calories per ounce of dry-roasted shelled nuts). About 40 shelled pea-nuts weigh an ounce (160-190 calories/ounce).

The Bad Nuts : Cashews, Macadamia Nuts, Brazil-nuts and Coconut contain in increasing order, greater amounts of saturated fat. Coconut is almost purely saturated fat. It should be avoided. Vegetables : Tasty, healthy and filling, often overlooked as snacks are cut-up vegetables, like carrots, cauli-flower, broccoli, celery, cucumbers, cabbage may be eaten raw or with a low-fat curds. Fast foods : Avoid fast-foods having high-calories and with saturated fats. Fats and Oils : The Poly-unsaturated fat to saturated fat ratio (P/S ratio) should be studied. P/S ratio of greater than or equal to 1 : 1 is considered good and a ratio less than 1 : 1 is considered bad. Olive-Oil : used as cooking medium by Greeks. Mainly Mono-unsaturated Fat and a little Poly un-saturated fat P/S Ratio 6 : 1. It is an ideal oil least risky with minimum heart

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disease. (Pea-nut oil is also mono unsaturated but causes clogging of coronary arteries. So why take a chance?) Second choice is vegetable oils with the lowest saturated fat content and highest Poly-unsaturated fat content. Safflower oil has a P/S ratio of 8.3 : 1. Sunflower oil has a P/S ratio 6.4 : 1, which is quite good. Corn-oil has 4.6 : 1 and Soyabean (4 : 1). On hydrogenation these poly-unsaturated oils are converted chemically to saturated oils and lose their some (or all) heart-healthy properties. Coconut oil has a P/S ratio of 0.02 : 1 and 106 sat-fat calories per tablespoon. So it is one of the most heart-risky fat known. All oils have equal calories : All the oils are really mixtures of poly un-saturated, mono-unsaturated and saturated fats. None contains only one type of fat. However, all the fats contain the same number of calories i.e. 9 calories per gram. All are high in calories and should be avoided as much as possible, especially by people trying to maintain their desirable weight. Risk Factors for CORONARY HEART DISEASE : (A) RISKS ONE CANNOT CONTROL : (i) (ii) (iii) Family History Sex Age

(B) RISKS WE CAN CONTROL : (i) (ii) Smoking : Smoking one pack a day doubles the risk of heart attack. Smoking more than one pack a day triples the risk. High Blood Pressure : Both High B.P. (Hypertension) and high blood cholesterol are silent killers.

These risks are additive. The presence of two risk factors quadruples the risk. (C) OTHER RISK FACTORS : (i) (ii) Diabetes : Diabetics have a two fold greater rate of coronary heart disease than do normal people. Obseity : Obseity is associated with higher rates of angina pectoris, stroke and sudden death. High B.P. and diabetes, riskfactors for heart-disease are 3 times more common in obese people. -9-

(iii) (iv)

Lack of Physical Exercise. High Blood Triglycerides : These levels can be reduced by physical activity, weight-loss (if obese), restriction of alcohol consumption, reduced intake of sweets and saturated fats.

Table : Cholesterol Contents of Selected Foods : (COMPILED FROM U.S.A. LITERATURE) Dairy Products 1. Butter 2. Cheese (i) (natural & processed) (ii) low-fat 3. Egg yolk 4. Milk Whole 20% Skim 5. Curds low-fat non-fat 6. Meat, Fish & Poultry (a) cooked pork, chicken, turkey, fish (b) Kidney, beef, cooked(c) liver (i) Chicken simmered (ii) Beef cooked (d) Scallops, cooked(Shell fish) (e) Shrimp cooked 7. Plant Products Fruits Grains Vegetables - 10 1 oz 1 oz 1 oz 1 oz 1 oz 1 oz 18-25 200 180 126 15 43 Qty. 1 pat Cholesterol (mg) 11

1 oz. 1 cup 1 large

16-35 10 274

1 cup 1 cup 1 cup 8 oz 8 oz

33 18 5 10-14 0-1

0 0 0

Vegetable oils

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