Dietary and Lifestyle Considerations for Colon Cancer
There is a 25-fold difference in geographical areas in incidence of colorectal cancers, within North America, Australia, New Zealand, Western Europe, and select areas of Eastern Europe having the highest rates. 102 People who migrate from low rate areas to high rate areas see an increase in development of colorectal cancers, indicating that the cultural environment and dietary habits contribute significantly to risk.103
In general, Western diets contain too much red meat and not enough fruits and vegetables compared to Non-Western diets. Fruits and vegetables, in addition to the vitamins, minerals and fiber they provide, contain thousands of other compounds (phytochemicals) that have anticancer effects. One class of phytochemicals that lessen cancer risk are the phenolic compounds, including hesperidin, anthocyanins, quercetin, rutin, epigallocatechin-3-gallate (EGCG), and resveratrol, among others.104-107
Many cultures outside the United States also use a more diverse and greater proportion of herbs and spices in their cooking. Many spices have anti-inflammatory effects and daily consumption of a variety of spices may contribute to the lower rates of colorectal cancers in non-Western cultures.108,109 Perhaps the most well studied spice with a potent anti-inflammatory action is turmeric, whose active ingredient is curcumin. Curcumin, through its modifying action of NF-kB, affects hundreds of molecules involved in proliferation, survival, migration and new blood vessel development.
While there is some controversy over the precise components of the diet that influence colorectal risk, there is no real debate that whole foods, with the nutrients and fibers intact, provide protection against colorectal cancers. A recent look at data from a study using the Dietary Approaches to Stop Hypertension (DASH) diet, which is high in whole grains, fruit, and vegetables; moderate amounts of low-fat dairy; and lower amounts of red or processed meats, desserts, and sweetened beverages, found the DASH diet reduced the risk of colon cancer by nearly 20% and rectal cancers by 27%.110
A healthy diet not only reduces risk, but appears to favorably affect outcomes once colon cancer has been diagnosed as well. A study of patients with stage III colon cancer divided their dietary habits into two dietary patterns. The “Prudent” pattern was characterized by high intakes of fruits and vegetables, poultry, and fish; and the “Western” pattern was characterized by high intakes of meat, fat, refined grains, and dessert. Those with Prudent diet had less recurrence of their colon cancer and were more likely to still be alive at the 5-year point.111
Population studies show that those who exercise have a reduction in the risk of developing many cancers, including breast, prostate, lung, pancreatic and colon cancer.112 A study in the Journal of the American Medical Association showed that overweight survivors of cancer who took part in nutritional improvement, exercise and modest weight loss had less functional decline than non-participants.113
Exercise may protect against the development of cancers by reducing the likelihood of obesity and/or diabetes, but there are other, more direct effects as well. Fat, or adipose tissue, releases chemical messengers called adipokines. These adipokines increase inflammation and create glucose dysregulation and other metabolic disturbances. Recently, myokines from muscle have also been discovered. These myokines, which are made when muscles contract, appear to have a cross-talk with the adipokines, and the net effect is that myokines lead to improved glucose utilization and less fat deposition.114 Therefore, usage of muscle and reduction of adipose through exercise results in a reduction of inflammation overall.
Maintaining normal weight protects against many cancers115 and may be one reason that diet and exercise are linked so strongly to the reduction of risk of colorectal cancer.116