April 20, 2010 – Eating oranges – and other citrus fruits – every day could reduce the incidence of cancer of all types by 15% to 20%, according to a Japanese study1. For pancreatic and prostate cancers, the relative risk reduction would be around 37%.
However, the preventive action of citrus fruits (orange, tangerine, lemon, lime, grapefruit, etc.) was only significant in participants who also consumed green tea on a daily basis.
The researchers followed, for 9 years, a cohort made up of 42,470 adults registered with a public health insurance plan. The participants, aged 40 to 79, were all in good health at the start of the study.
The results indicate that the protective effect against cancer is proportional to the amount of citrus consumed: subjects who consumed them every day had better protection than those who ate only 3 or 4 times a week. In addition, the researchers did not observe a protective effect against cancer for green tea which was not accompanied by daily consumption of citrus fruits.
“Various components of citrus fruits and green tea would have a complementary action which could explain the preventive effect observed in this study”, affirms the principal investigator of the study, Wen-Qing Li.
Citrus consumption was assessed using a questionnaire on participants’ eating habits (40 foods and drinks). The study authors then analyzed this data based on the incidence of cancer cases diagnosed during the study.
Pierre Lefrançois – PasseportSanté.net
1. Li WQ, Kuriyama S, Li Q, et al. Citrus consumption and cancer incidence: the Ohsaki cohort study. Int. J. Cancer, February 2010.
