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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
Allyl sulfides
(garlic, onions, chives, leeks)
Cruciferous vegetables
Indoles/glucosinolates
(broccoli, cauliflower,
Sulfaforaphane
cabbage, Brussels sprouts,
Isothiocyanates/thiocyanates
kale, turnips, bok choy,
Thiols
kohlrabi)
Solanaceous vegetables
Lycopene
(tomatoes, peppers)
Umbelliferous vegetables
Carotenoids
(carrots, celery, cilantro,
Phthalides
parsley, parsnips)
Polyacetylenes
Compositae plants (artichoke)
Silymarin
Citrus fruits
Monoterpenes (limonene)
(oranges, lemons, grapefruit)
Carotenoids
Glucarates
Other fruits (grapes, berries,
Ellagic acid
cherries, apples, cantaloupe,
Phenols
watermelon, pomegranate)
Flavonoids (quercetin)
Beans, grains, seeds
Flavonoids (isoflavones)
(soybeans, oats, barley, brown
Phytic acid
rice, whole wheat, flax seed)
Saponins
Protease inhibitors
Herbs, spices (ginger, mint,
Gingerols
rosemary, thyme, oregano,
Flavonoids
sage, basil, tumeric, caraway,
Monoterpenes (limonene)
fennel)
Licorice root
Green tea
Glycyrrhizin Catechins
Polyphenols
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 healthcare 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.
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