This is one of the few lectures that will be given on nutrition at my medical school. Have fun tearing it up
The major features of the diet for the prevention and treatment of coronary artery disease is that it is low in cholesterol, low in fat and saturated fat and, reciprocally, high in complex carbohydrate and fiber.
The first objective is to reduce cholesterol consumption from 400-500 to <100 mg/day (note that
only foods of animal origin contain cholesterol).
This requires keeping egg yolk consumption to a minimum, since much of the dietary cholesterol comes from egg yolk. Half of this is from visible eggs and half from eggs incorporated into processed foods. Lean red meat and poultry are emphasized as well as increased consumption of fish. Nonfat dairy products are recommended.
Cholesterol: 100 mg
Salt: 1 teaspoon
Cholesterol: 400-500 mg
Salt: 2 1/2 teaspoons
The second objective is to decrease the current saturated fat intake by two-thirds, from
12 to 5% of calories. This requires eating red meat or cheese to no more than twice a week, using lower-fat cheeses (20% fat or less), limiting ice cream and chocolate to once a month, using soft margarines and oils sparingly and avoiding products containing coconut and palm oil.
The major plasma cholesterol elevating effects of a given food reside in its cholesterol and
saturated fat content. To help understand the contribution of these two factors in a single food item and to compare one food with another, we have computed a cholesterol-saturated fat index (CSI) for selected foods. The formula for the CSI is:
CSI = (1.01 x g saturated fat) + (0.05 x mg cholesterol), where the amounts of saturated fat and cholesterol in a given amount of a food item are entered into this equation.
The higher the CSI of a food, the greater the hypercholesterolemic and atherogenic effect. This cholesterol-saturated fat index is a representation of how much a given food will decrease the activity of the LDL receptor and, hence, raise the level of LDL cholesterol in plasma. Worldwide the CSI of a countryâ??s diet is highly correlated with the mortality from coronary heart disease.
In this context it is particularly instructive to compare the CSI of fish versus that of
moderately fat beef, both being 85 g portions. An 85 g portion of cooked fish contains 58 mg of
cholesterol and 0.31 g of saturated fat. This contrasts to 72 mg cholesterol and 10.3 g of saturated fat in 85 g of 30% fat beef. The CSI for beef (14) is almost 5 times greater than for fish (3). The caloric value of these two portions also differs greatly (100 kcals for fish and 310 kcals for beef).
The CSI of cooked chicken and turkey (without the skin) is also lower than that of beef and other red meats and the total fat content is considerably lower. The saturated fat in an 85 g serving of poultry is 1.5 g, the cholesterol is 71 mg and the CSI is 5. Shellfish have low CSIs because their saturated fat content is extremely low despite the fact their cholesterol or total sterol content is 2.5 to 3 times higher than fish, poultry or red meat.
Three-ounce portions of shellfish have an average CSI of 4. When considering both cholesterol and saturated fat, shellfish like poultry, is a better choice than even the leanest red meats. Even though salmon is a higher fat fish, it has a low CSI and is the preferred choice over red meat and even poultry.
The third objective is to reduce fat intake by one-half from 40 to 20% of calories.
can be done by avoiding fried foods, reducing the fat used in baked goods by one-third and using low-fat dairy products. A good guide to use in selecting foods is to choose main dishes with no more than 10 grams of fat per serving. For other dishes choose those with no more than 5 grams of fat per serving. Added fat should be limited to two teaspoons per day for women and children and four teaspoons per day for teenagers and men. Peanut butter should be eaten no more than twice a week as part of a meal and not as a snack; nuts, olives and avocados used sparingly as condiments.
The daily fat allowance in calories and grams for a 20% fat diet is given below:
THE 20% FAT DIET: DAILY FAT ALLOWANCE IN CALORIES & GRAMS
Calorie levels Daily Fat Allowance Appropriate for
1200 240 27 Weight loss
1600 320 36 Weight loss
2000 400 44 Women/children
2400 480 53 Women
2800 560 62 Men/teens
3200 640 71 Men/teens/exercisers
3600 720 80 Exercisers
When people are advised to decrease the amount of fat in their diets, they usually think only
of visible fat and are surprised to learn that visible fat such as spreads and salad dressings represents only 22% of their total fat intake. Decreasing dietary fat would be very difficult without knowing that 78% is invisible, with the majority coming from red meat, cheese, ice cream and other dairy products, baked products and fat used in food preparation.
The fourth objective is to increase the intake of omega-3 fatty acids from seafood.
Omega-3 fatty acids from seafood have important effects whether or not the diet is high in saturated fat. In either instance, omega-3 fatty acids produced a lowering of plasma cholesterol, triglyceride and especially VLDL, about 50%. With a low saturated fat diet, the plasma cholesterol is lowered by as much as 25%. Thus, an ideal diet would be low in saturated fat and high in omega-3 fatty acids.
It is not known exactly how much the intake of omega-3 fatty acids should be increased to
achieve optimum effect. One study from the Netherlands indicated that men who included fish in
their diet twice a week had fewer deaths from heart disease. A similar protective effect from eating fish occurred in a Seattle study. Men who ate a weekly meal of salmon had a fifty percent reduction in cardiac arrest, a most compelling statistic. In a prospective trial in Wales, the prescription of two fatty fish meals per week led to both a reduction in total mortality and in coronary events.
Even very low-fat seafood contains an appreciable amount of omega-3 fatty acids, up to 40 percent or more of total fatty acids. Eating a total of 12 ounces of a variety of fish and shellfish each week would provide 3 to 5 grams of omega-3 fatty acids as well as protein, vitamins and minerals. The fish could be fresh, frozen or canned without affecting the quantity of omega-3 fatty acids. The patient with hyperlipidemia can only expect to have such beneficial effects from following this dietary advice, if fish replaces red meat in the diet since meat is a major source of saturated fat.
Also to be considered are the antithrombotic actions of fish oil mediated through inhibition of the thromboxane A2 in platelets (39) and the enhanced clearance of chylomicrons. Other effects of fish oil include inhibition of platelet-derived growth factor, alteration of certain functions of leukocytes, reduction of blood viscosity, greater fibrinolysis, inhibition of intimal hyperplasia in vein grafts used for arterial bypass and, most recently, reduced risk of primary cardiac arrest.
Fish oil serves as a therapeutic agent in certain hyperlipidemic states, especially the chylomicronemia of type V hyperlipidemia. Thus, fish oils have not only discrete effects upon the plasma lipids and lipoproteins but also upon the atherosclerotic and thrombotic process.
The fifth major dietary objective is to increase the complex carbohydrate and fiber
content. If dietary fat is reduced from 40% to 20% of calories and protein kept constant at 15% of calories, then carbohydrate intake must be increased from 45% to 65% of total calories. In practical terms, this means that at least two complex carbohydrate-containing foods should be eaten at each meal.
For example, eating toast and cereal for breakfast, a sandwich (2 slices of bread) or bean soup and nonfat crackers at lunch and 1-2 cups of rice, pasta, potatoes, corn, etc. with bread at dinner. Snacks should be of a complex carbohydrate type, such as baked chips, popcorn or low-fat crackers and low-fat cookies. This is a significant change as most Americans currently limit carbohydrate foods to no more than one per meal.
To reach the increased carbohydrate objective, the patient must also eat 3-5 cups of legumes per week, 2-4 cups of vegetables per day and 3-5 pieces of fruit per day with a concomitant decrease in refined sugar intake from 20% of calories to 10%. This means that sweets (pop, candy or baked desserts) are limited to no more than two servings per week. While research increasingly supports the value of a high carbohydrate diet, many people are reluctant to adopt it because “starchy” foods are associated with weight gain because they are typically combined with foods high in fat and calories (oil, cheese, sour cream, etc.).
Patients need recipes and convenience foods that combine complex carbohydrates with lowfat ingredients and provide tasty dishes. The carbohydrate objective, however, is essential if the fat intake is reduced and body weight is to be maintained.
The treatment and prevention of coronary heart disease involves BIG CHANGES in eating
style!! My motto is “From Meat to Beans in 10 Short Years”. This involves changing from the
typical U.S. diet to the NCEP Step 1 diet of 30% fat (making substitutions) to the NCEP Step 2 diet of <30% fat (eating meatless, cheeseless lunches and trying new recipes) to a maximal lipid lowering diet of 20% fat (doing every day what one used to do once a week).
Phase I – NCEP Step 1 Diet
â?¢ Avoid foods high in cholesterol and saturated fat
Delete egg yolk, butterfat, lard, organ meat
Vegetable oils (Canola, olive, etc.) for shortening
Skim milk for whole milk
Egg whites and egg substitute for whole eggs
Fish, chicken and leaner meats for fatter meats
Nonfat or low fat dairy products for typical versions
â?¢ Use Lite Salt
These are the changes that are required in order to meet the guidelines of the NCEP Step 1 diet in which 30% of the calories are from fat and 50% are from carbohydrate. Changing from the typical US intake to this eating style will lower the plasma total and LDL cholesterol 5 to 7%, on the average.
Phase II – NCEP Step 2 Diet
â?¢ Gradual transition to eating meat once a day
â?¢ Use less fat and cheese
â?¢ Eat more fruits, grains, beans and vegetables
â?¢ Use products that contain less salt (salt reduced chicken
broth, no salt added tomatoes and tomato sauce, etc.
â?¢ Acquire new recipes
These are the changes that are required in order to meet the guidelines of the NCEP Step 2 diet in which <30% of the calories are from fat and 50+% of calories are from carbohydrate. Changing from the typical US intake to this eating style will lower the plasma total and LDL cholesterol 10 to 14%, on the average.
Phase III – (Maximal Lipid Lowering Diet
â?¢ Use meat as a condiment (3-4 oz a day)
â?¢ Use low CSI cheeses
â?¢ Decrease amount of salt used in cooking
â?¢ Save these foods for use on special occasions:
These are the changes that are required in order to meet the guidelines of a maximal lipid lowering diet in which 20% of the calories are from fat and 65% of calories are from carbohydrate. People need to change slowly and gradually by trying new recipes and new food products one at a time and incorporating those they like into their lifestyles. How far and how fast one progresses depends on the motivation for trying new recipes and new products.
People need to have continual exposure to new foods and recipes if a new eating style is to be established. Eating styles are continually being remodeled so people need continual inspiration. Most of what people eat should come from foods as they exist in nature. Science wonders such as fat free baked goods, fat free frozen yogurt, wine, etc. are best considered as â??spices.â?? People should choose among the â??spicesâ?? to enhance their lowfat, high complex carbohydrate eating styles.
Changing from the typical US intake to this eating style will lower the plasma total and LDL
cholesterol 15 to 20%, on the average (5 to 7% per phase, on the average).
USA Diet I II III
Plasma Cholesterol, mg/dl
The facts all add up to this–It is very important to keep building the fence around the cliff to keep ourselves and our children from falling offâ??PREVENTION – by flossing our teeth, wearing our seat belts, getting plenty of exercise, never smoking and, of course, working on a lower fat, higher complex carbohydrate way of eating.