An Evaluation of the Evidence Associating the Phenolic Phytochemicals in Food With Cancer Chemoprevention

• Published in: Journal of the American Dietetic Association 1996-09, Vol.96 (9), p.A55-A55
• Main Authors: King, Amy J.G., Youez, Gloria
• Format: Article
• Language: English
• ISSN: 0002-8223; 1878-3570
• DOI: 10.1016/S0002-8223(96)00497-X

LEARNING OUTCOME: TO inform dietitians about the anticancer activity of food phenolic phytochemicals so that they can respond accurately when asked if certain foods prevent cancer. Phytochemicals are promoted as possible anticancer agents and the popular literature has sensationalized the health benefits of phytochemicals. Phenolic phytochemicals are one class of phytochemicals and flavonoids are the most ubiquitous phenolics. We reviewed over 60 scientific publications to assess the anticancer activity of food phenolic phytochemicals. The anticancer activities of plant phenolics include antioxidant ability, affecting enzyme systems involved in carcinogenesis, inhibiting the growth of tumors in lab animals and inhibiting the growth of human cancer cells in vitro. Total flavonoids were not associated with reduced cancer risk in the only known large-scale epidemiological study done to date. The conclusions we drew were: (1) phenolic phytochemicals are biologically active in mammals; (2) phenolic phytochemicals can be anticarcinogenic in laboratory animals when introduced as aglycones at relatively high concentrations; (3) the study of plant phenolics as cancer chemopreventers is at an early stage. Many characteristics of plant phenolics are still unclear, i.e. the mechanism by which they exert their anticarcinogenic activity, whether they inhibit spontaneously occurring cancer in lab animals, how they are metabolized by humans, and if their presence and level in human diets correlates with decreased cancer risk at specific sites. If food phenolic phytochemicals were found to be anticarcinogenic in humans, and if their anticancer mechanisms were understood, dietitians could recommend specific foods to clients at high risk for developing specific cancers. Investigating the over one thousand year old Chinese practice of using food to mediate disease would benefit the research in this area. Currently, there is not enough evidence for phenolic phytochemicals as cancer chemopreventers to allow dietitians to recommend certain foods as anticancer agents. The current evidence does strengthen the National Cancer Institute's recommendation to eat more fruits and vegetables.