Joseph A Rothwell1, Viktoria Knaze, Raul Zamora-Ros. 1. aNutrition and Metabolism Section, Biomarkers Group, International Agency for Research on Cancer (IARC), Lyon, France bUnit of Nutrition and Cancer, Cancer Epidemiology Research Programme, Catalan Institute of Oncology, Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Spain.
Abstract
PURPOSE OF REVIEW: Polyphenols are a large and diverse family of phytochemicals widely consumed by humans. Here we summarize the latest epidemiological evidence for associations between cancer risk and polyphenol intake, taking into account difficulties in the accurate estimation of exposure. RECENT FINDINGS: Flavonoids are the most studied subgroup of polyphenols with regard to cancer risk. In recent epidemiological studies, total flavonoid intake has rarely been associated with a reduction in cancer risk. However, isoflavones, whose main dietary source is soy foods, plausibly reduce the risk of colorectal, breast, and prostate cancers, especially in Asian countries. Findings depend heavily upon the assessment of polyphenol intake, which is usually measured by food frequency questionnaires coupled to databases of food polyphenol composition. To a lesser extent, nutritional biomarkers have been used whenever estimating associations of polyphenol intake with cancer. SUMMARY: Polyphenol intake may mitigate cancer risk but this depends on cancer site, the subgroup of compounds under study, and accurate assessment of dietary exposure. Further work must better characterize the effects of intake of different flavonoid subclasses and begin to investigate the role of phenolic acids and other minor polyphenol classes.
PURPOSE OF REVIEW: Polyphenols are a large and diverse family of phytochemicals widely consumed by humans. Here we summarize the latest epidemiological evidence for associations between cancer risk and polyphenol intake, taking into account difficulties in the accurate estimation of exposure. RECENT FINDINGS:Flavonoids are the most studied subgroup of polyphenols with regard to cancer risk. In recent epidemiological studies, total flavonoid intake has rarely been associated with a reduction in cancer risk. However, isoflavones, whose main dietary source is soy foods, plausibly reduce the risk of colorectal, breast, and prostate cancers, especially in Asian countries. Findings depend heavily upon the assessment of polyphenol intake, which is usually measured by food frequency questionnaires coupled to databases of food polyphenol composition. To a lesser extent, nutritional biomarkers have been used whenever estimating associations of polyphenol intake with cancer. SUMMARY:Polyphenol intake may mitigate cancer risk but this depends on cancer site, the subgroup of compounds under study, and accurate assessment of dietary exposure. Further work must better characterize the effects of intake of different flavonoid subclasses and begin to investigate the role of phenolic acids and other minor polyphenol classes.
Authors: Michał Wiciński; Jakub Gębalski; Ewelina Mazurek; Marta Podhorecka; Maciej Śniegocki; Paweł Szychta; Ewelina Sawicka; Bartosz Malinowski Journal: Nutrients Date: 2020-01-29 Impact factor: 5.717