The latest issue of the Journal of American Medical Association (JAMA) has a very interesting study on the effect of increased vegetable and fruit consumption (High Fiber Diet) on breast cancer patients.
There has been significant evidence (in the scientific literature) that foods, and especially plant-derived foods (fruits and vegetables), contain cancer fighting compounds. A 1997 publication on Food and Cancer established that high vegetables /fruit diets probably decreases breast cancer risk and, on the contrary, high total fat diets possibly increases cancer risk. The information on Breast cancer and the relationship with diet is somehow confusing and mixed on the positive effects of high fiber diets.
The study’s (see reference bellow for original paper) purpose was to evaluate if an increase in the consumption of vegetables, fruits, and fiber, and a decrease in fat has an effect on the risk of recurrent and new breast cancer development. Also, it examined if such high-fiber/limited fat intake may have an effect on the all-cause mortality rate among women with previously treated early stage breast cancer.
The study included a sample of 3000 individuals divided in two groups of about 1500 patients each. One of the group (the test group-1537 patients) received a counseling program in addition to cooking classes and newsletter so as to promote a 5 vegetable servings a day plus a daily 16 oz juice plus a 3 serving of fruits (for a total o eight-a-day combined fruit and vegetable services). The control group (1551 patients) received material to promote the 5-a-day dietary guidelines.
Participants were enrolled at 7 study sites between 1995 and 2000. Patients were followed by a little more than 7 years to assess mortality rates an breast cancer events.
The study was designed to test whether the new dietary pattern (the 8-a-day fruits and veggie diet) is associated with a increased overall survival among women previously treated for early stage breast cancer. Also, the study examined if the new diet may induce or reduce the breast cancer event-free interval (the time between episodes of breast cancer events).
The study employed a computational analysis of data which showed that there was not significant differences between both the test and the control group in relation to survival rates and overall risk of breast cancer.
This means that a 5-a-day vegetable servings is enough for your fiber needs in relation to the effect that they may have on breast cancer risk. Just continue to eat your daily 5 servings of fruits and vegetable. Is not worth to go over it to protect yourself, at least, for breast cancer, and according to this study.
Steinmetz KA, Potter JD. (1991). Vegetables, fruit, and cancer, II: mechanisms. Cancer Causes Control. 2(6): pages 427-442
World Cancer Research Fund. Food, Nutrition and the Prevention of Cancer: A Global Perspective. Washington, DC: World Cancer Research Fund, American Institute for Cancer Research; 1997.
Pierce et. al . 2007. Influence of a Diet Very High in Vegetables, Fruit, and Fiber and Low in Fat on Prognosis Following Treatment for Breast Cancer. The Women’s Healthy Eating and Living (WHEL) Randomized Trial. JAMA. Vol. 298 (3) : pages 289-298