In an effort to prevent colon cancer, we're told to eat less meat, fatty foods and desserts and more fruits, vegetables and whole grains. According to a study published today in the Journal of the American Medical Association, this advice can also keep the cancer from coming back. Nutrition expert Leslie Beck provides some insight into the study.
Q: Do we know what foods can help prevent colon cancer recurrence?
No, we really don't. Although many studies have investigated the link between certain foods and the risk of developing colon cancer in the first place, very few studies have looked at dietary factors that can improve survival. Two recent studies did find that regular exercise reduced the risk of colon cancer recurrence by as much as 50 per cent.
Q: What foods increase the risk of colon cancer recurrence?
In the study, researchers from the Dana-Farber Cancer Institute in Boston, Massachusetts examined the influence of certain eating patterns on colon cancer recurrence in 1,009 patients diagnosed and treated for stage III colon cancer (cancer present in the colon and the lymph nodes). Patients were then followed up for cancer recurrence or death for 5.3 years.
The researchers examined the impact of two dietary patterns on cancer recurrence and survival: a "Western" diet (higher intakes of red and processed meats, sweets, desserts, fatty foods, refined grains) and a "prudent" diet (higher intakes of fruit, vegetables, legumes, fish, poultry, whole grains). Among individuals who adhered to a Western eating pattern, those who had the highest intake of these types of foods were 3.3 times more likely to have their cancer return or die, compared to those who ate less of them. In contrast, the prudent eating pattern was not significantly related to cancer recurrence or survival.
For colon cancer survival eat less:
- Red and processed meat
- Sweets and desserts
- Fatty foods
- Refined grains
These findings suggest that when it comes to improving colon cancer survival, it's what you don't eat that matters. Reducing consumption of red meat, fatty foods, sugary desserts and refined grains is an additional step colon cancer patients can take to improve their outcome.
Q: What makes the combination of foods in the Western diet increase the risk of colon cancer recurrence?
The researchers hypothesized that, following surgery for stage III colon cancer, eating the combination of foods typical of a Western diet could allow residual microscopic cancer to proliferate and spread. Scientists have long suspected that certain foods or food components may work together to increase the risk of colon cancer. Western dietary patterns have been linked with higher levels of insulin and inflammatory compounds in the body, factors that may enhance tumor growth.
Q: What should be the diet to prevent colon cancer in the first place?
Studies suggest that red meat, processed meat, animal fat, sugary foods, refined grains and alcohol increase colon cancer risk, while whole grains, calcium, vitamin D and folic acid lower the risk.
Eat less meat.
- Many studies show that people who eat the most red meat (beef, veal, pork, lamb) and/or processed meat (luncheon meat, bacon, hot dogs, sausages) are more likely to get colon cancer than those who eat these foods occasionally.
- Meat might boost colon cancer risk in a few ways. In lab animals, compounds formed when meat is cooked have been shown to cause colon tumours. The form of iron in red meat - heme iron - may also damage colon cells and trigger cancer growth. And it's thought that nitrites in some processed meats may form cancer-causing compounds.
- If red meat is eaten at all, limit your intake to less than three ounces (90 grams) per day. Choose fish chicken, turkey, legumes, tofu and soy foods more often.
Limit fatty foods.
- Studies suggest that the more animal (saturated) fat people eat, the more likely they are to get colon cancer. Fatty foods might induce the cancer by increasing the secretion of toxic bile acids into the colon and stimulate the production of insulin. Limit your intake of fatty meats, ice cream, cheese, and rich desserts. Choose lean meats, poultry breast, and non-fat dairy products. Use higher fat spreads like butter and cream cheese sparingly if at all.
Increase whole grains.
- The relationship between a high fibre diet and colon cancer risk remains unclear, but evidence suggests that eating more whole grains can lower the risk. In a 2007 study of almost 500,000 men and women, aged 50 to 71, whole grain intake - but not total fibre - was protective. Participants who ate the most whole grain were one-fifth as likely to develop colorectal cancer compared to those who ate the least.
- Whole grains such as barley, brown rice, oats, whole wheat, whole rye and quinoa contain a "package" of nutrients and phytochemicals that are thought to work together to guard against from cancer.
Reduce alcohol.
- In a study of more than 45,000 male health professionals, drinking more than two alcoholic drinks per day doubled the risk of colon cancer. Based on these and other similar findings, cancer experts advise if you drink at all to limit alcohol intake to seven drinks per week (women) and nine per week (men).
- Alcohol may stimulate the growth of colon cancer cells, activate cancer-causing substances, and help transform of polyps into cancer. Alcohol also interferes with the body's use of folate, a B vitamin needed for the repair of DNA in cells. If you do drink, increase your intake of folate-rich foods such spinach, lentils, asparagus, avocado and oranges.
Be active.
- Regular exercise has been shown to reduce the risk of colon cancer by 30 to 40 per cent. Exercise stimulates peristalsis, a wave-like muscular contraction that helps move waste through the colon. Regular exercise can also lower levels of certain hormones and insulin that can promote cancer growth.
