Diet and colorectal cancer: Review of the evidence.
OBJECTIVE
To investigate whether diet has a role in the development and progression of colorectal cancer (CRC).


METHODS
MEDLINE was searched from January 1966 to December 2006 for articles on the relationship between diet and CRC using the key words colorectal cancer and folic acid, calcium, vitamin D, red meat, or fibre. Evidence that these factors are associated with CRC came from case-control and prospective cohort studies and some clinical trials.


RESULTS
Whether red meat is a culprit in causing CRC remains unanswered, although any effect it might have is likely moderate and related to processing or cooking. The effect of dietary fibre on risk of CRC has also been difficult to determine because fibre intake is generally low. Evidence that folic acid, calcium, and vitamin D reduce risk of CRC is stronger. In particular, recent research indicates that calcium and vitamin D might act together, rather than separately, to reduce the risk of colorectal adenomas. There might also be an interaction between low folate levels and high alcohol consumption and CRC.


CONCLUSIONS
Before dispensing dietary advice, physicians should understand the potential benefits and harm of specific components of various foods. People might be able to reduce their risk of CRC by increasing their vitamin and mineral levels through eating more vegetables and fruit. Multivitamin and mineral supplements can complement a healthy diet.
Ryan-Harshman
Milly
M
947 Oshawa Blvd N, Oshawa, ON L1G 5V7. ryanharshman@rogers.com
Aldoori
Walid
W
D002170:Canada; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000517:prevention & control*; D004032:Diet; D004041:Dietary Fats / Q000008:administration & dosage; D004043:Dietary Fiber / Q000008:administration & dosage*; D019587:Dietary Supplements; D019317:Evidence-Based Medicine; D005260:Female; D005638:Fruit; D006801:Humans; D015994:Incidence; D008297:Male; D015596:Nutrition Assessment; D011379:Prognosis; D018570:Risk Assessment; D014675:Vegetables
D004041:Dietary Fats; D004043:Dietary Fiber