Frequent Fruit and Vegetable Consumption May Not Protect From Colorectal Cancer
For immediate release: October 31, 2000
BOSTON, MA--Results from the largest research study to date on the topic indicate that frequent consumption of fruit and vegetables may not reduce the risk of cancer of the colon or rectum. Researchers from Brigham and Women’s Hospital (BWH) and the Harvard School of Public Health (HSPH) used data from more than 135,000 women and men from two large sources--the Nurses' Health Study and the Health Professionals' Follow-up Study. The finding are published in the November 1 issue of the Journal of the National Cancer Institute.
"Certainly, this research does not mean that eating fruits and vegetables has little value. Overall, fruits and vegetables remain an essential part of a healthy diet, contributing to our overall health and reducing risk for many other chronic diseases," explained lead researcher, Dr. Karin B. Michels, Assistant Professor at Harvard Medical School and Clinical Epidemiologist at Brigham and Women's Hospital. "What this study indicates is that fruits and vegetables may be less important for preventing colorectal cancer than adopting other diet and lifestyle changes."
Continued Dr. Michels, "Past studies have lead to the currently held belief that fruits and vegetables protect from cancer. Most of these studies, however, were done retrospectively--people were asked what they ate after they had already developed cancer. Reporting of diet may have been influenced by the disease. Furthermore, studies were rather inconsistent in their findings."
Specifically, the women in the BWH/HSPH study were followed for 16 years, the men for 10 years, and their diet was assessed repeatedly during these years. During that time, 1181 participants were diagnosed with colon or rectal cancer which were documented with medical records. But a low consumption of fruit and vegetables did not seem to be associated with the occurrence of these cancers.
The latest findings add to the growing evidence that the role of diet in cancer may be less important than previously assumed. Fiber has also been found to be of little importance in the development of colorectal cancer and the recurrence of polyps, a precursor of colorectal cancer.
Dr. Michels suggests that other components of diet may influence colon cancer risk. "The link between red meat consumption and colorectal cancer has been found in most studies and is well supported by evidence. Changes in lifestyle and diet in adult lives have been found to affect colorectal cancer risk.
Dr. Michels concluded, "A large number of colorectal cancers can be avoided by a healthy lifestyle including regular exercise, multivitamin supplements, and avoiding obesity, large amounts of red meat, smoking and excessive alcohol consumption."
The BWH and HSPH researchers also point out that regular screening for colon cancer can both help prevent the disease by removing polyps and reduce mortality by detecting cancers in an early stage.
For further information, please contact:
Maggie Hayden (BWH) 617-732-5527
Office of Communications
Harvard School of Public Health
677 Huntington Avenue
Boston, MA 02115