For many years, researchers have recognized that diets high in fruits, vegetables, grains, and legumes appear to reduce the risk of a number of diseases, including cancer, heart disease, diabetes, and high blood pressure when compared with diets high in meat. More recently, it was discovered that the disease-preventing effects of these foods are partly due to antioxidants - specific vitamins, minerals, and enzymes that help prevent cancer and other disorders by protecting cells against damage from oxidation. Now, researchers have discovered that fruits, vegetables, grains, and legumes contain yet another group of health-promoting nutrients. Called phytochemicals, these substances appear to be powerful ammunition in the war against cancer and other disorders.

Phytochemicals are the biologically active substances in plants that are responsible for giving them color, flavor, and natural disease resistance. To understand how phytochemicals protect the body against cancer, it is necessary to understand that cancer formation is a multistep process. Phytochemicals seem to fight cancer. For instance, cancer can begin when a carcinogenic molecule - from the food you eat or the air you breathe - invades a cell. But if sulforaphane, a phytochemical found in broccoli, also reaches the cell, it activates a group of enzymes that whisk the carcinogen out of the cell before it can cause any harm.

Other phytochemicals are known to prevent cancer in other ways. Flavonoids, found in citrus fruits and berries, keep cancer-causing hormones from latching onto cells in the first place. Genistein, found in soybeans, kills tumors by preventing the formation of the capillaries needed to nourish them. Indoles, found in cruciferous vegetables such as Brussel sprouts, cauliflower, and cabbage, increase immune activity and make it easier for the body to excrete toxins. Saponins, found in kidney beans, chickpeas, soybeans, and lentils, may prevent cancer cells from multiplying. P-coumaric acid and chlorogenic acid, found in tomatoes, interfere with certain chemical unions that can create carcinogen. The list of these protective substances goes on and on. Tomatoes alone are believed to contain an estimated 10,000 different phytochemicals.

Although no long-term human studies have shown that specific phytochemicals stop cancer, research on phytochemicals supports the more than 200 studies that link lowered cancer risk with a diet rich in grains, legumes, fruits, and vegetables. Moreover, animal and in vitro studies have demonstrated how some phytochemicals prevent carcinogens from promoting the growth of specific cancers. For instance, the phytochemical phenethyl isothiocyanate (PEITC), found in cabbage and turnips, has been found to inhibit the growth of lung cancer in rats and mice. Among other things, PEITC protects the cells' DNA from a potent carcinogen found in tobacco smoke.

Researchers have been able to isolate some phytochemicals, and a number of companies are now selling concentrates that contain phytochemicals obtained from vegetables such as broccoli. These may be used as supplemental sources of some of these nutrients. However, such pills should not be seen as a replacement for fresh whole foods. Because severeal thousand phytochemicals are currently known to exist, and because new ones are being discovered all the time, no supplement can possibly contain all of the cancer-fighters found in a shopping basket full of fruits and vegetables.

Fortunately, it is easy to get a healthy dose of phytochemicals at every meal. Almost every grain, legume, fruit, and vegetable tested has been found to contain these substances. Moreover, unlike many vitamins, these substances do not appear to be destroyed by cooking or other processing. Genistein, the substance found in soybeans, for instance, is also found in soybean products such as tofu and miso soup. Similarly, the phytochemical PEITC, found in cabbage, remains intact even when the cabbage is made into cole slaw or sauerkraut. Of course, eating much of your produce raw or only lightly cooked, you will be able to enjoy the benefits of not just phytochemicals, but of all of the vitamins, minerals, and other nutrients that fresh whole foods have to offer.

Foods That Fight Disease:
A simple Guide to Using and Understanding Phytonutrients to Protect and Enhance Your Health
By Laurie Deutsch Mozian

PowerFoods: Good Food, Good Health with Phytochemicals, Nature's Own Energy Boosters
By Stephanie Beling

Ohio State University Extension Fact Sheet Family and Consumer Sciences 1787 Neil Avenue, Columbus, Ohio 43210 Phytochemicals - Vitamins of the Future? HYG-5050-98 Sereana Howard Dresbach Amy Rossi Recently, you may have heard the words chemoprevention, nutraceuticals, and phytochemicals in the media. What exactly do these terms mean? With the ever-increasing interest in improving our health, it is important to understand these words and understand their function in health care. The information presented here will provide a basis for deciphering the mixed messages that are being delivered in the media, conversations, research, and education. Research has demonstrated that cancer is a largely avoidable disease. It is estimated that more than two-thirds of cancer may be prevented through lifestyle modification (1). Nearly one-third of these cancer occurrences can be attributed to diet alone, secondary to our American diet of high-fat, low-fiber content. Fruit and vegetable consumption have been consistently shown to reduce the risk of many cancers (2). A major prevention strategy has been the "5 A Day for Better Health" program sponsored by the National Cancer Institute (NCI), encouraging the public to include more fruits and vegetables in their diet. The American Cancer Society has developed guidelines for nutrition and cancer prevention. These guidelines are similar to the Dietary Guidelines for Americans and include the following: Choose most of the foods you eat from plant sources. Limit your intake of high-fat foods, particularly from animal sources. Be physically active. Achieve and maintain a healthy weight. Limit consumption of alcoholic beverages if you drink at all. The guideline stating to "choose most of the foods you eat from plant sources" has been recognized for years as important for good health. The Food Guide Pyramid illustrates this recommendation. More importantly, recent research has begun describing properties, specifically chemicals, contained in fruits, vegetables, grains, legumes, seeds, licorice root, soy, and green tea. Chemical compounds found in these foods are being recognized for their potential for protection against heart diasease and cancer. This fact sheet will describe phytochemicals, identify the foods in which they are found, and suggest ways to obtain them from the diet. Current "Buzzwords" in Nutrition Chemoprevention -- Using one or several chemical compounds to prevent, stop, or reverse the development of cancer. Designer Food -- Processed foods that are supplemented with food ingredients naturally rich in disease-preventing substances (5). Functional Food -- Any modified food or food ingredient that may provide a health benefit beyond the traditional nutrients it contains (6). Nutraceutical -- Specific chemical compounds in food, including vitamins and additives, that may aid in preventing disease. Pharmafood -- Food or nutrient that claims medical or health benefits, including the prevention and treatment of disease (7). Phytochemical --Nonnutrient plant chemicals that contain protective, disease-preventing compounds. What are phytochemicals? Phytochemicals are nonnutritive plant chemicals that contain protective, disease-preventing compounds. More than 900 different phytochemicals have been identified as components of food, and many more phytochemicals continue to be discovered today. It is estimated that there may be more than 100 different phytochemicals in just one serving of vegetables (6). As early as 1980, the National Cancer Institute Chemoprevention Program of the Division of Cancer Prevention and Control began evaluating phytochemicals for safety, efficacy, and applicability for preventing and treating diseases. Researchers have long known that there are phytochemicals present for protection in plants, but it has only been recently that they are being recommended for protection against human disease. Most Commonly Studied Phytochemicals Food Phytochemical(s) Allium vegetables (garlic, onions, chives, leeks) Allyl sulfides Cruciferous vegetables (broccoli, cauliflower, cabbage, Brussels sprouts, kale, turnips, bok choy, kohlrabi) Indoles/glucosinolates Sulfaforaphane Isothiocyanates/thiocyanates Thiols Solanaceous vegetables (tomatoes, peppers) Lycopene Umbelliferous vegetables (carrots, celery, cilantro, parsley, parsnips) Carotenoids Phthalides Polyacetylenes Compositae plants (artichoke) Silymarin Citrus fruits (oranges, lemons, grapefruit) Glucarates Monoterpenes (limonene) Carotenoids Other fruits (grapes, berries, cherries, apples, cantaloupe, watermelon, pomegranate) Ellagic acid Phenols Flavonoids (quercetin) Beans, grains, seeds (soybeans, oats, barley, brown rice, whole wheat, flax seed) Protease inhibitors Flavonoids (isoflavones) Phytic acid Saponins Herbs, spices (ginger, mint, rosemary, thyme, oregano, sage, basil, tumeric, caraway, fennel) Gingerols Flavonoids Monoterpenes (limonene) Licorice root Green tea Polyphenols Glycyrrhizin Catechins There are also hundreds more phytochemicals existing and in need of discovery! How are they beneficial? Although phytochemicals are not yet classified as nutrients, substances necessary for sustaining life, they have been identified as containing properties for aiding in disease prevention. Phytochemicals are associated with the prevention and/or treatment of at least four of the leading causes of death in the United States -- cancer, diabetes, cardiovascular disease, and hypertension (7). They are involved in many processes including ones that help prevent cell damage, prevent cancer cell replication, and decrease cholesterol levels. Specifically, the economic cost of cancer to society was estimated to be about $104 billion in 1997 (8). With health-care costs being a major issue today, it would be cost effective to continue the research needed to help promote the awareness and consumption of phytochemicals as a prevention strategy for the public. Can I just take a pill containing these substances? Americans spend approximately $2-2.5 billion a year on vitamin/mineral supplements (9). It should be expected that extracted phytochemicals will be, if not already, available for consumer purchasing. Consumption of supplements containing phytochemicals will only provide selected components in a concentrated form, not the diversity of compounds that occur naturally in foods (10). It is important to continue the effort to encourage increased fruit, vegetable, and grain consumption to acquire the benefits of phytochemicals versus simply ingesting a pill containing these substances. Researchers continue to investigate the interactions of phytochemicals naturally present in food. It would be difficult to extract phytochemicals from plants for supplement use before understanding the synergistic effect of all phytochemicals present. Are there any negative effects? Individual phytochemicals are being evaluated for their safety and effectiveness in regard to disease prevention. Although most studies support positive outcomes, there are a few studies involving animals that show possible detrimental effects. These studies involve animals and specific extracted phytochemicals in high dosages. The safety of consuming large amounts of fruits, vegetables, and grains is not presently a concern. The research question being asked is: "Should one increase the intake of a particular plant food containing phytochemicals, and how much should they increase it?" Obviously, like any other newly discovered chemical, there is a need for further investigation for potential health benefits and possible health risks. Optimal levels of phytochemicals have yet to be determined. In addition, requirements during disease states may differ from requirements for prevention of heart disease and cancer. Individual recommendations in terms of requirements for different genders, age groups, body types, and so forth also need further study. How can I incorporate more phytochemicals into my diet? First, it is important for Americans to become aware of their lack of consumption of fruits, vegetables, and grains. The average American consumes only one serving of vege-tables and one serving of fruit each day (11). In one survey, one in every nine Americans ate no fruit or vegetable on the day they were interviewed (12). Increasing the consumption of plant products in one's diet should not be difficult or time consuming. There are plenty of simple strategies for increasing dietary fruits, vegetables, and grains, including the suggestions below: Keep fruits and vegetables (fresh, frozen, and canned) stocked and in sight. Reach for juice instead of coffee or soda. Add chopped fruit to cereal, yogurt, pancakes, muffins, or even a milkshake. Snack on fresh chopped carrots, celery, broccoli, cauliflower, and peppers (purchase at a salad bar to save time). Add fresh greens, carrots, celery, parsley, tomatoes, and/or beans to your soups. Store dried fruit (apricots, dates, raisins, and more) for a quick snack at home or work. There are also several other easy methods for increasing fruits, vegetables, and grains in your lifestyle. Why not challenge yourself and create one of your own? Good Luck! Conclusion It was once stated that our health is a "gift" -- a largely controllable gift (13). We can control this gift through lifestyle choices of our own. These choices include the foods we choose to eat. Research has demonstrated the tremendous potential of phytochemicals in regard to prevention and treatment of disease. Now, it is the responsibility of not only health-care professionals, but also individuals to begin the conscientious effort of improving their diet. Even though phytochemicals are readily available in today's food supply, it is highly possible that future foods may undergo bioengineering or fortification to enhance naturally occurring phytochemical concentrations. This would make it even easier to incorporate phytochemicals in the diet. The research involving phytochemicals is promising, but with any newly discovered chemical, it is recommended that further studies be conducted. This fact sheet was designed to introduce the discovery and importance of phytochemicals. It is in no way intended to replace your health-care provider's recommendations. As with any health recommendation, it is advisable to check with your physician before adapting any lifestyle changes. References 1. Oliveria, S. A. et al. 1997. The Role of Epidemiology in Cancer Prevention. The Soc for Exp Bio and Med 216:142-150. 2. Block, G. et al. 1992. Fruit, vegetables, and cancer prevention: A review of the epidemiologic evidence. Nutr Cancer 18:1-29. 3. Mirvish, S. S. et al. 1975. Induction of mouse lung adenomas by amines or ureas plus nitrite and by N-nitoso compounds: effect of ascorbate, gallic acid, thiocyanate, and caffeine. J Natl Cancer Inst 55:633-636 4. Thomas, P. R., R. Earl. Eds. 1994. Opportunities in the Nutrition and Food Sciences, Research Challenges and the Next Generation of Investigators. National Academy Press. 5. Bloch, A. et al. 1995. Position of the American Dietetic Association: Phytochemicals and functional foods. JADA.95: 493-496. 6. Polk, Melanie. 1996. Feast on Phytochemicals. AICR newsletter. Issue 51. 7. Bloch, A. et al. 1995. Position of the American Dietetic Association: Phytochemicals and functional foods. JADA.95: 493-496. 8. American Cancer Society. Cancer Facts & Figures 1997. Atlanta, GA: American Cancer Society. 9. Reynolds, R. D. 1994. Vitamin supplements: current controversies. J Am Coll Nutr 13(2): 118-126. 10. Bloch, A. et al. 1995. Position of the American Dietetic Association: Phytochemicals and functional foods. JADA.95: 493-496. 11. Craig, W. 1996. Phytochemicals: Guardians of our health. JADA. 97(10): S199-S204. 12. Craig, W. 1996. Phytochemicals: Guardians of our health. JADA. 97(10): S199-S204. 13. Malaspina, Alex. 1996. Functional Foods: Overview and Introduction. Nutr Reviews 54(11): s4-s10. All educational programs conducted by Ohio State University Extension are available to clientele on a nondiscriminatory basis without regard to race, color, creed, religion, sexual orientation, national origin, gender, age, disability or Vietnam-era veteran status. Keith L. Smith, Associate Vice President for Ag. Adm. and Director, OSU Extension. TDD No. 800-589-8292 (Ohio only) or 614-292-1868

LINKS

Molecular Expressions: The Phytochemical Collection With Graphics

Nutraceuticals Phytochemicals Phytonutrients - Nutritional Value

Phytochemicals, Food Resource, Oregon State University

Module 2: Phytochemistry

Boehringer-Ingelheim.com: Phytochemical Products

University of Missouri: Diet & Disease Educational Support Materials - Phytochemicals

CancerStory.com: Phytochemicals, Cancer Plants

AmericanHeart.org: Phytochemicals & Cardiovascular Disease

Alternative Medicine: Phytochemical Links

Phytochemicals: Guardians of Our Health

You Become What You Eat - Phytochemicals - Guarding the Gates