Although there isn't a lot of research to date on phytochemicals, experts say that they are generally healthy and safe when eaten as part of a balanced diet containing a wide range of fruits and vegetables. What raises concern is when they are ingredients in nutritional supplements, which are not regulated by the Food and Drug Administration.
Supplements cannot begin to replicate the wide variety of phytochemicals that occur naturally in foods; and in high concentrations, they might actually be dangerous. Certain phytochemicals in supplements have in fact been found to contribute to cancer cell growth. Beta-carotene, although it can be beneficial when taken naturally, has been found to increase the risk of lung cancer in male smokers when taken in a high-dose supplement. Some flavonoids can cause serious gastrointestinal or allergic problems when taken in high doses.
For more information on phytochemicals and related topics, check out the links on the next page.
- How Antioxidants Work
- How B Vitamins Work
- How Cancer Works
- How Food Works
- How Heart Disease Works
- How Organic Food Works
- How Vitamin C Works
More Great Links
- Food and Nutrition Information Center
- National Institutes of Health: Office of Dietary Supplements
- 5 A Day for Better Health: The Power of Phytochemicals
- USDA Phytonutrient Laboratory
- U.S. Food and Drug Administration: Dietary Supplements
- "The Importance of Good Nutrition, Herbs and Phytochemicals: For Your Health, Good Looks and Longevity" by Getty T. Ambau
- "PowerFoods: Good Food, Good Health with Phytochemicals, Nature's Own Energy Boosters" by Stephanie Beling
- "Designing Your Life With Designer Foods: The Facts About Phytochemicals" by Neecie Moore
- "Eat to Heal: The Phytochemical Diet and Nutrition Plan" by Kristine M. Napier
- American Heart Association, Phytochemicals and Cardiovascular Disease.
- "Antioxidants May be Responsible for the 'French Paradox." Nutrition Research Newsletter, March 1993.
- Craig, Winston J., Ph.D.Phytochemicals: Guardians of Our Health. Vegetarian Nutrition.
- Webb, Densie. Phytonutrients: The hidden keys to disease prevention, good health. Environmental Nutrition, January 2003, Volume 26, page 1.
- Hackman, Robert. "Flavonoids and the French Paradox - Unhealthy-living French Have Low Rate of Heart Attacks." USA Today, September 1998.
- Howard, Barbara V., Ph.D., and David Kritchevsky, Ph.D. "Phytochemicals and Cardiovascular Disease," Circulation 1997; 95:2591.
- National Cancer Institute, The Power of Phytochemicals.
- New York Methodist Hospital, What are Important Foods?
- Phytochemicals - Vitamins of the Future? Ohio State University Extension Fact Sheet.
- The Phytochemical Collection, Florida State University.
- What are Vitamins, Carotenoids, and Phytochemicals?