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LAURA
PENSIERO, R.D., SUSAN
OLIVERIA, Sc.D. M.P.H., MICHAEL OSBORNE, M.D. Whether or not they want to admit it, Americans are having a love affair with fat. An oily substance that is one of the principal components of living cells, fat is essential in the diet; however, too much fat puts people at risk for significant health complications. Many elements of American cuisine include fat: T-bone steaks, dairy products, salad dressings, condiments (sour cream, cream cheese, butter), and processed foods (commercial chips, cookies, and crackers). Other cultures offer diets richer in fruits, vegetables, and whole grains. Because Americans consume more fat, their incidence of heart disease and cancer is significantly higher than that of people who eat a traditionally low-fat diet. To lower your risk of both heart disease and cancer, it is recommended that you limit your fat intake to 20 to 25 percent of your total calories (in some instances underlying medical conditions warrant lower or higher fat intakes). Because individuals require different amounts of calories, fat intake is expressed as a percentage of caloric intake. The guideline of 20 to 25 percent should not be used for individual foods, but for your whole day or even week. If your average fat intake in a meal is 40 percent of calories, you can offset it by limiting two or more subsequent meals to 15 to 20 percent. In addition, you may have a day where your fat intake is at 40 percent of calories; you can come out even if you balance total fat intake for the next two days at 15 to 20 percent of calories. This amount allows for moderate portions of animal protein and limited amounts of added fat in cooking and seasoning of food and even an occasional rich dessert. The best way to stay close to this guideline is to assess your daily target for maximum amount of fat in grams. Once you know the number of grams of fat you can consume each day, reading labels and making decisions becomes much easier. To assess your daily fat intake: 1.
Determine your daily calorie requirements (see page 19). Example: If you require 1,800 calories a day: 0.20 X 1,800 = 360 (fat calories). 360/9 calories/gram = 40 grams of fat per day. If you don't want to do the math, refer to the table below after assessing your caloric requirements.
To figure out the percentage of calories from fat in a meal, recipe, or food product: 1. Determine the number of grams of fat. 2. Multiply the grams of fat by 9 (every gram of fat has 9 calories)-this will provide the total calories from fat. 3. Divide this number by the total number of calories from the meal or food. 4. Multiply by 100 and you will have the percentage of calories from fat. Example: If a recipe contains 300 calories and 10 grams of fat: 10 grams fat X 9 calories per gram = 90 calories from fat. 90 fat calories divided by 300 total calories = 0.30 x 100 30 percent calories from fat. Beware: fat grams add up quickly. A tablespoon of olive oil in a homemade salad dressing will cost you 15 grams; a small serving (4 ounces) of meat, fish, or poultry can be 10 to 15 grams; each teaspoon of butter, regular margarine, and other oils is another 5 grams. That's why it's important to moderate your intake of lean protein sources and added fats. The "Nutrition Facts" labels of commercial food products contain information on the fat content of particular foods in the "Total Fat" section that you can use to choose products that fit into your total fat allotment for the day. Be sure to adjust for the portion size you actually consume. Not all fat is created equal. Dietary fat is composed of two major types of fatty acids: saturated and unsaturated. Unsaturated fatty acids are further classified as either polyunsaturated or monounsaturated. Foods that contain fat usually have a combination of all three fatty acids, although they are generally classified by the predominant fatty acid. Saturated Fats Saturated fats are "saturated," or loaded, with the hydrogen atoms they carry. You should make the greatest effort to avoid these fats. A diet high in saturated fat can lead to high blood cholesterol levels, and may be associated with increased risk of certain types of cancer. Saturated fats are usually solid at room temperature, and are the visible fats that you can see in foods such as bacon. Although saturated fat comes in the highest ratios in foods of animal origin (beef, lamb, pork, veal, poultry, and full-fat dairy products), some vegetable-based products, such as coconut and palm oils (used in commercial baked goods) and solid vegetable shortenings, contain saturated fat. Coconut and palm oils, in fact, derive approximately 86 percent of their calories from saturated fat. The vegetable oils in many commercial food products also undergo a solidifying process called hydrogenation, that further increases their levels of saturation. Hydrogenation is the process used to make vegetable shortenings and margarine. Cholesterol Cholesterol is a waxy fat like substance. Your body needs some cholesterol to help form cell walls, hormones, and vitamins. But too much cholesterol in your bloodstream can cause fatty deposits to build up on artery walls. This can lead to heart attacks and strokes. Blood cholesterol comes from two sources. Your liver makes all the cholesterol your body needs. Blood cholesterol levels are also related to the foods that you eat, particularly foods high in saturated fat. Surprisingly, the cholesterol found in food has less influence on blood cholesterol levels than does saturated fat. This type of cholesterol is called dietary cholesterol and it is found only in foods of animal origin, such as butter, dairy products, and meats. So it's not such a big deal when a food label says cholesterol free for a product such as peanut butter or vegetable oil, because these foods have always been cholesterol free. Don't be confused: cholesterol free does not mean fat free! Some plant foods that are high in saturated fat, such as coconut and palm oils, do not contain cholesterol. Even though the relationship between dietary cholesterol and cancer is not strong, you should limit your intake of foods that contain substantial amounts of cholesterol because they generally contain high levels of saturated fat, which has been associated with cancer. Unsaturated Fats Olive oil is a type of unsaturated fat called monounsaturated. Olive oil is the predominant dietary fat source in Mediterranean countries like Greece, Italy, and Spain. The rate of breast cancer in these countries is lower than that of the United States (even though the overall total fat intake is about the same). A few epidemiologic studies suggest that olive oil is beneficial in reducing breast cancer risk, but research in this area is continuing. It has been shown that monounsaturated fat (in place of saturated fat) has a positive effect on blood lipid (fat) levels. Monounsaturated fat reduces "bad" low-density lipoprotein (LDL) cholesterol and elevates the levels of "good" high-density lipoprotein (HDL) cholesterol, reducing the risk of heart disease. Another type of unsaturated fat, polyunsaturated, is made up of omega-6's, found in vegetables, and omega-3's, which are most often present in fatty fish. Some plants have the potential to provide omega-3 fatty acids. The body can convert linolenic acid, a type of fat found in canola oil, flaxseeds, soybeans, walnuts, and some leafy green vegetables, into omega-3 fatty acids. Moderate dietary intake of omega-3 fatty acids, found in substantial amounts in salmon, bluefish, swordfish, trout, tuna, and striped bass, may have a protective effect against heart disease and certain types of cancer. Interest in the omega-3 fatty acids has been based on the observation that cancer rates are lower in populations where the diet is composed of a high proportion of these fatty acids. When compared to diets that contain omega-6 fatty acids from vegetable oils like corn and safflower, diets that contain a high proportion of omega-3 fatty acids have been shown to slow or prevent the growth of tumors, particularly mammary and colon tumors in animals, possibly by inactivating hormones that promote certain cancers. Other beneficial effects of omega-3 fatty acids include reduction of cholesterol and triglyceride levels and lowering of blood pressure. They may also improve symptoms of inflammatory diseases like rheumatoid arthritis and ulcerative colitis, as well as immune function. The omega-6's and their effect on cancer risk has also been a focus of interest. It appears that certain polyunsaturated fats may actually increase the risk for some cancers; however, this has been shown mainly in animal studies with little support from human data. The relationship between omega-3 fatty acids and omega-6 fatty acids is competitive and interrelated. When dietary intake of one is out of proportion, the other can control important biochemical reactions in the body. Researchers believe that a 1:1 ratio of omega-3 to omega-6 may he important in the prevention of heart disease. The American diet contains about ten omega-6's to one omega-3. This disproportion may lead to the overproduction of hormones, which in turn can cause formation of blood clots, promote the buildup of plaque on artery walls, and disturb immune function. A healthy immune system is vital to warding off certain types of cancer. Here are some ways to increase your omega-3 intake. 1. Include an omega-3-rich fish source in your diet two to three times per week. 2. Sprinkle whole flaxseed on rolls, muffins, or breads before baking or add it to waffles, pancakes, muffins, or quick breads. For more information about flaxseed and its uses, contact the Flax Council of Canada (800) 817-9894, or visit their web site at http://www.flaxcouncil.ca. 3. Substitute ground flax flour for up to 10 percent of the flour in baked goods. Because of its high fat content (omega-3's), cut the fat in the recipe by up to one-third by replacing the moisture with water, juice, or fruit puree. 4. Use all oils sparingly, and use olive, canola, flaxseed, soybean, and walnut oils more frequently than other vegetable oils. 5. Limit omega-6-rich foods, such as salad dressings, margarine, and mayonnaise. 6. Avoid fish oil capsules unless prescribed by your physician. The most concentrated source of omega-3' s, these supplements can cause overdose, which may lead to excessive bleeding, increased risk of hemorrhagic stroke, adverse drug interactions, and, in some instances, high cholesterol. Fatty Acid Food Sources High in Monounsaturated Fatty Acids Best Sources Good Sources High in Polyunsaturated
Fatty Acids corn oil
Good Sources Moderate Sources PLANT SOURCES OF OMEGA,3's (linolenic acid): canola oil It is acknowledged that some fats are better than others with respect to prevention of heart disease and cancer, but your total fat intake should be moderate. This will help keep you at an appropriate weight and will lower your risk for many chronic diseases, including heart disease and cancer. Does this mean the less fat you eat the healthier you will be? Not necessarily; it is possible to eat too little fat. Fat serves several vital functions in the body. Fats carry vitamins A, D, E, and K across the intestinal wall into the bloodstream. In fact, vitamin E is found predominantly in fatty foods of plant origin. Essential fatty acids, such as linolenic and linoleic, which are provided only through the diet, are needed to make hormones and maintain healthy cells. Over a long period of time, diets with less than 10 percent of calories from fat can put you at risk for vitamin and essential fatty acid deficiencies. Diets high in saturated and hydrogenated fat (the kind found in commercial snack foods and baked goods) can also lead to essential fatty acid deficiency if they are low in monounsaturated and polyunsaturated fats. The bottom line is to go easy on the fat-free and other processed foods. Moderation and variety are the keys to balancing your fat intake.
Decreasing the amount of fat you eat can be achieved with a little planning and good decision making when shopping, cooking, and dining out. By using good quality cooking equipment, some of today's hottest chefs have refined the art and techniques of healthy cooking. A sampling of their methods include high temperature oven roasting (for meat, fish, poultry, fruits, and vegetables), searing food in nonstick pans to achieve flavor and browning, and using fruit and vegetable purees to replace some or all of the fat in soups, sauces, and baked goods. By applying some of their basic techniques and making healthy substitutions for high-fat ingredients, you can substantially cut the amount of fat in your diet and never miss it. COOKING AND BAKING 1. Trim the fat off meat and limit portion sizes. 2. Bake, broil, roast, boil, braise, sear, saute (with minimal oil or stock in a nonstick skillet), steam, or grill rather than fry. 3. Roast firm-fleshed fish, such as snapper, halibut, or cod, "en papillotte" (in paper). Inside the fold of parchment paper, sprinkle the fish with fresh herbs and a splash of white wine (or broth). Seal at the edges with egg whites, folding over repeatedly. Well-sealed foil wrap can also be used. This method of cooking really concentrates the flavors of the herbs and fish, allowing you to forget all about fat. 4. Use a rack in the pan when cooking meats to allow fat to drip down. 5. Use nonstick pans and bakeware to limit the amount of fat in cooking and baking. Use a limited amount of fat (about 1/2 teaspoon per serving) to saute or sear food in a nonstick pan. Heating oil until it is very hot-almost smoking-and then turning down the heat to medium-high before adding the food will help to achieve good browning and flavor with a minimum of fat. 6. Saute foods in broth, water, or wine instead of butter or oil. 7. Steam or oven-roast vegetables. 8. Prepare soups and stocks at least a day in advance so that fat can be skimmed off the top more easily. Add starches such as beans (cooked), peas, potatoes, or rice when preparing soup. Cook until tender, then puree all or half of the soup. The starch will give it a creamy consistency and will thicken the soup. 9. Limit the use of butter, margarine, oils, cream, regular salad dressing, lard, commercial baked goods (containing hydrogenated fats or tropical oils such as palm and coconut), and shortening. 10. Try nonfat powdered milk in baking. Low-fat baked goods typically do not brown well. Adding one or two tablespoons of dry milk will help you to achieve a golden brown color. 11. Halve the amount of fat called for in savory recipes, such as soups, stews, sauces, and casseroles. 12. When baking, use fruit purees made from apples, bananas, prunes, soy, or flaxseed flour to replace part of the fat. Replace unsweetened chocolate with unsweetened cocoa powder: for every ounce of chocolate, substitute 3 tablespoons of cocoa. Because fat adds flavor to baked goods, enhance flavor by increasing or adding ingredients such as citrus zests, various extracts, and sugar when you cut fat from a recipe. SUBSTITUTE... 1. fish, poultry without skin, and lean meats for higher fat meats 2. nonfat or I percent milk for whole milk 3. low-fat or fat-free sour cream for the full-fat versions; I or 2 percent milk or half the amount of fat-free sour cream for cream in "cream" soups and sauces 4. 1 cup of milk mixed with I tablespoon of cornstarch or '/4 Cup of evaporated skim milk mixed with I tablespoon of all-purpose flour for cream in cooking. Whisk the mixture into a soup or sauce and bring to a boil. Reduce the heat and maintain a low boil until creamy and slightly thickened, about two minutes (the cornstarch or flour will prevent the milk from breaking when heated). 5. 1 whole egg plus 2 egg whites for 2 whole eggs in cooking and baking reduced-fat cheeses, such as cottage, part-skim mozzarella and ricotta, farmer, soy, for high-fat cheeses; and lower-fat versions of Swiss, Cheddar, goat's milk, and cream cheeses. 6. soy sausages for regular sausages to add flavor (and protein) to a soup or stew; smoked turkey or lean smoked ham in bean soups that call for hocks 7. fruit or vegetable salsas, chutneys, or flavorful mustards for mayonnaise on sandwiches 8. pureed I percent or nonfat cottage cheese or "yogurt cheese" for mayonnaise as a sandwich spread or as a base for dressings adding fresh herbs or seasonings, such as tarragon, thyme, parsley, cilantro, saffron, curry, cayenne, tomato paste or pureed sun-dried tomatoes, and a pinch of olive or anchovy paste 9.pureed I percent or nonfat cottage cheese for ricotta cheese in cooking and baking 10. acidic dairy products, such as yogurt or buttermilk, for part of the liquid ingredients in baking to help prevent gluten (a protein found in flour) from developing and tenderize the baked goods. 11. turkey or chicken breast (skin removed) or tuna salad (prepared with a small amount of olive oil, reduced-fat mayonnaise, or mustard) for high-fat luncheon meats, such as bologna, ham, or salami 12. fresh fruit, pretzels, baked tortilla chips with salsa, raw vegetables, air-popped popcorn, low-fat cheese, whole-grain low-fat crackers, flavored rice cakes, cereal, or sorbet for high-fat snacks, such as potato chips, cold cuts, high-fat cheese, cookies, chocolate, nuts, or ice cream 13. small portions of low-fat or fat-free sweets for the regular versions. (Remember, they still have calories!) 14. broth-based or vegetable puree soups for cream-based soups 15. high-fiber, low-fat breakfast cereals or a bagel with a light layer of reduced-fat cream cheese (or any other type of low-fat cheese) for high-fat muffins or scones; include a piece of fruit with your breakfast to add nutrients and replace fat. 16. thin-crust pizza topped with vegetables for pizza with sausage or pepperoni; blot any surface fat with a napkin LAURA
PENSIERO, R.D., SUSAN OLIVERIA, Sc.D.
M.P.H., MICHAEL OSBORNE, M.D. Carbohydrates are the major energy source in the human diet. They are the least expensive energy source and the majority of the world's population relies on carbohydrates to meet most of its energy requirements. Foods rich in complex carbohydrates (starches or fiber) are generally rich in vitamins, minerals, and phytochemicals. The calories derived from fruit are almost exclusively from carbohydrates. Grains, cereals, legumes and vegetables contain protein and, in some cases fat, but they are composed of significantly more carbohydrate by weight. Carbohydrates are chemical ring compounds made solely of carbon, oxygen, and hydrogen. The number and structure of the rings determine the type of carbohydrate. Carbohydrates are distinguished as simple carbohydrates, containing one or two rings, or complex carbohydrates, containing many rings. Complex carbohydrates are further differentiated as starches, which are digestible, and fiber, which is not digestible. Simple carbohydrates include monosaccharides (fructose, glucose, and galactose) and disaccharides (sucrose, maltose, and lactose) that are split when digested. Common simple sugars include sucrose (fructose and glucose joined together), what we call table sugar; fructose, the main sugar in fruit (also used to make the high fructose corn syrup used in many commercial products); and lactose (glucose and galactose) found in milk. Many other words that appear in ingredients lists indicate that the product contains sugar. If you are trying to moderate your intake of empty calories from sugar, look for the following ingredients (the higher they appear in ingredients lists, the greater the amount present): beet
sugar
Fact: Although sugar should not be a major component of your diet, especially if you are watching calories, researchers have not found a direct link between sugar and ill health. There are medical conditions, such as diabetes and elevated trigylcerides (a type of fat found in the bloodstream), that do warrant restrictions on sugar and other simple carbohydrates, but for most people, sugar intake does not impose health dangers. Furthermore, all types of sugars (and complex carbohydrates) are broken down to the body's primary energy source, glucose. Whether refined or unrefined, sugar is not a source of any major nutrient except calories. For this reason, you should limit your sugar intake to leave room for nutrient-packed complex carbohydrates. LAURA
PENSIERO, R.D., SUSAN
OLIVERIA, Sc.D. M.P.H., MICHAEL OSBORNE, M.D. Getting enough protein is rarely a health concern for most Americans. The average American less than sixty-five years of age consumes 50 percent more protein than the Recommended Dietary Allowance (RDA) (46 to 63 grams per day for adults, depending on age and sex). Two-thirds of the protein intake is from meat, fish, poultry, or dairy; the remaining one-third is from plant sources, such as legumes, grains, cereals, and vegetables. Animal protein sources provide high-quality protein and vitamins B6, B1 2, and zinc (nutrients that are hard to get from a strict vegetarian diet), and contain a form of iron that is easily absorbed by the body. However, they also contain significant amounts of total fat, saturated fat, and cholesterol. Researchers have linked diets high in animal protein to increased risk of heart disease and certain types of cancer. People whose intake of protein is moderate and more predominantly from plant sources consume less fat and more fiber, vitamins, minerals, and other substances such as phytochemicals. They are healthier in general and are less prone to these diseases. Why are high protein diets so popular? Every decade or so high protein diets are repackaged as a "new" concept for weight loss. The most recent wave of these books blames the increase in obesity on excessive carbohydrate intake, which supposedly causes insulin resistance and thus weight gain in many people. In fact, the relationship between insulin resistance and obesity is just the opposite: insulin resistance is often the result of obesity, not the cause of it. Furthermore, these diets "work" by limiting food choices and food groups and, in the final analysis, total calories. Most nutrition experts agree that weight control is a matter of "calories in = calories out." Whenever calorie intake exceeds calories burned, whatever the source of the calories-carbohydrate, protein, or fat-the excess will he stored as fat. The exceptions to this rule are rare medical conditions that cause irregular metabolism or interfere with the body's ability to digest and absorb nutrients. As for the safety of high-protein diets, there is no evidence that protein intake up to 50 percent greater than the RDA poses detrimental health consequences, provided that intake of animal protein and fat are not excessive and the individual does not have any conditions or diseases that compromise kidney function. In the long run, however, these diets can be problematic if protein foods replace fruits, vegetables, and high fiber grains and cereals. How Much Protein Do You Need? The protein RDA for adults is 0.8 grams per kilogram of body weight or 0.36 grams per pound of body weight. For a
125-pound (57-kg) female = 125 X 0.36 equals 45 grams protein/day When
you consider that an 8-ounce steak (half the portion served in many restaurants)
provides approximately 56 grams of protein, you realize how easy it is
to get adequate protein and even more. By keeping animal protein at around
6 ounces per day (two 3-ounce servings), while increasing plant protein
sources, you will meet key nutrient requirements (vitamin B12, iron, and
zinc) and at the same time be moderating your total fat, saturated fat,
and cholesterol intake. PROTEIN SOURCES Lean Protein Sources MEAT/POULTRY/GAME/FiSH AND SHELLFISH (6 to 8 grams protein per ounce) BEEF
Fresh pork tenderloin is a terrific alternative protein source for those who are all "chickened out." It is almost as lean as skinless chicken breast, and is very tender. Pork tenderloin and loin chops cook quickly, so be careful not to overcook. Searing, grilling, roasting, or braising are other cooking techniques to consider for these cuts of pork. Another form of pork, extra-lean ham, can be as low in fat as 1.5 grams per ounce; however, you should still limit consumption because even "fresh" hams often contain nitrites. Sources
Sources
(skin removed)
As consumer demand for game has increased in recent years, different varieties have become more available in some supermarkets, gourmet specialty shops, and from butchers. Many types of game can also be purchased through mail order sources. Wild game tends to have even less fat than ranch-raised varieties; however, the taste is typically more "gamey" and is not quite as tender. Because game meat tends to be so lean, it will dry out quickly, particularly when roasting. Be careful not to overcook it. For nonpoultry game such as buffalo, elk, or venison grill or sear quickly (medium rare to medium) in a hot nonstick pan with a little oil. This will preserve juices and tenderness. Other cooking methods for boar, rabbit, or venison include careful roasting or braising in flavorful liquids such as stocks, fruit juices, wines, or combinations. Flavorings and seasoning, which compliment game include: fresh herbs such as thyme, rosemary, sage (for stronger flavored game), and tarragon; frozen, fresh, or dried berries (great additions to a sauce, and fresh and dried berries are nice garnishes); juniper berries; peppercorns; currant preserves; and roasted garlic. Sources FISH AND SHELLFISH Even some fattier fish, high in good omega-3 fatty acids, are low in total fat as compared with many other protein sources. There are many varieties of fish with 3 or less grams of fat per serving. To keep the fat down in these already low-fat protein choices, avoid breading and frying and heavy butter and/or cream-laden sauces. Use simple cooking techniques such as grilling, roasting, pan searing, poaching, or steaming to keep the fat low and allow the full flavors of the fish to come through. LOW-FAT
DAIRY Sources Milk
and Yogurt (portion sizes as indicated) Cheeses
(labeled "low-fat"-7 to 10 grams protein per ounce; portion
size is 1 oz.)
PLANT PROTEIN SOURCES After computing your daily protein requirement, note how easy it is to achieve it with plant sources alone. Plants that are good protein sources also tend to be rich ill fiber, vitamins, minerals, and protective phytochemicals. The macronutrient profile of most plant foods is a mixture of carbohydrate and protein. Fat levels will vary from none to quite high. Sources
LAURA
PENSIERO, R.D., SUSAN
OLIVERIA, Sc.D. M.P.H., MICHAEL OSBORNE, M.D. Vitamins and minerals are nutrients that are present in food but can also be obtained from vitamin supplements (pill form). Since a beneficial effect of fruits and vegetables on cancer risk has been consistently observed in studies, it is reasonable to think that the vitamins and minerals contained in fruits and vegetables might protect against cancer. The role of particular vitamins and minerals in the prevention of cancer has been investigated in studies. Although vitamins and minerals do not definitively prevent cancer, anticancer properties have been observed for certain cancers. VITAMINS, MINERALS, AND CANCER Antioxidants: Vitamins A, C, E, and Selenium Carotenoids.
Overall, a high intake of carotenoids (those which are vitamin A precursors
and include beta-carotene) has been linked to a decreased risk of many
cancers, including endometrial, stomach, ovarian, breast, colon, pancreatic,
prostate, bladder, cervical, lung, oral cavity, esophageal, and laryngeal. Other Vitamins and Minerals Calcium
and vitamin D. A link between increased intake of calcium and vitamin
D and reduced risk of colon cancer has been proposed, although the evidence
is not convincing at this time.
Antioxidants, Free Radicals, and Cancer Antioxidants act as scavengers of "free radicals," by-products of normal metabolism, before they can cause harm to the body. Free radicals are missing an electron (a negatively charged particle) from their chemical structure and are thus highly unstable. Because of their unstable nature, they can undergo a process called oxidation, the process whereby free radicals take electrons and transfer them, leaving a new free radical. This is damaging to the body's cells and will continue as a chain reaction unless an enzyme or free radical scavenger (antioxidant) stops the process. If left
unchecked, free radicals can cause oxidative damage: genetic damage, uncontrolled
cell growth and cancer, heart disease and other degenerative diseases,
and aging. Exposures to certain environmental factors, including radiation,
ultraviolet light, alcohol, cigarette and marijuana smoke, air pollutants,
smog, pesticides, herbicides, drugs, fried foods, inflammation, and very
strenuous physical activity (such as marathon running), can promote the
production of these free radicals. However, normal metabolism is responsible
for most free radical production. Although many studies suggest that vitamins protect against certain forms of cancer, the evidence is not compelling enough to "prove" vitamins protect against cancer. Nevertheless, we do know that diets high in vitamin- and mineral-rich fruits and vegetables definitely protect against many forms of cancer. Even if the studies on vitamins and minerals do not provide conclusive evidence of a beneficial effect, it is prudent for all people to follow the recommendations of eating five to nine servings of fruits and vegetables each day.
Carotenoids
(including Beta-Carotene) Vitamin
A (Preformed Retinol) Vitamin
C Vitamin
E Selenium Calcium Vitamin
D Folic
acid (Folate) Magnesium
Vitamin and Mineral Supplements Studies that have specifically looked at vitamin and mineral supplements (as opposed to vitamins from food sources) have shown a decreased risk of some cancers: individuals who take vitamin E supplements are at a reduced risk of oral, prostate, and colon cancer and are protected against heart disease; vitamin A supplementation has been shown to protect against colon and breast cancer; and vitamin C supplementation decreases the risk of breast, colon, and bladder cancer. Selenium supplementation reduces the risk of lung, prostate, and colorectal cancer. However, research conducted to date does not support a strong effect of vitamin and mineral supplements per se on cancer risk. Before vitamin supplementation is recommended for preventing cancer, its role in cancer prevention needs more research; however, there may be a positive effect of vitamin supplementation for people from countries that have high rates of stomach and esophageal cancer. Studies of vitamin supplementation (vitamin A, zinc, riboflavin, betacarotene, vitamin E, and selenium) have been conducted in China, where the rate of both esophageal and stomach cancer is high. The results show that vitamin A, zinc, and riboflavin taken together reduces the risk of esophageal cancer, whereas betacarotene, vitamin E, and selenium may be beneficial for stomach cancer. The idea of taking a vitamin supplement to compensate for deficiencies in their diet appeals to many people. Although the chemical structure of a particular vitamin supplement is the same as that of the vitamin found in food sources, absorption and utilization by the body may be different. It is known that diets rich in foods containing certain vitamins and minerals help to prevent cancer; however, these foods may contain other substances, such as phytochemicals, that work in conjunction with vitamins and minerals to confer benefit.
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