Scientists are studying how avoiding excess inflammation, keeping a healthy population of gut bacteria, limiting carcinogen exposure, and supporting normal cell processes may all guard against colon cancer, one of the most preventable forms of cancer. Fortunately, eating choices can provide protection on multiple fronts.
“Inflammation is one of several hallmarks of cancer,“ notes Cynthia Thomson, PhD, RD, professor and oncology researcher at the University of Arizona. Studies consistently link inflammation with development, progression, and prognosis of several cancers. No single food causes or prevents inflammation, but together, dietary choices add up to play a role. Overall eating habits likely to promote inflammation, as estimated by the Dietary Inflammatory Index, link to greater risk for several cancers, Thomson says.
The community of bacteria and other microbes in our digestive tract may support anti-inflammatory and other defenses against colon cancer. According to Johanna Lampe, PhD, RD, of Fred Hutchinson Cancer Center, these bacteria metabolize components in food to substances that may have beneficial or harmful effects on the gut or, if absorbed, can have broader effects on cancer risk. Lampe explains, “Many natural compounds from plant foods are not active in the body, but substances bacteria produce from them have been associated with lower risk of colorectal cancer.”
Four Strategies to Lower Colon Cancer Risk
These strategies combine what research ties to lowering colon cancer risk with steps that reduce inflammation and support healthy gut microbes.
1. Say Yes to Fiber. Each 10 grams of fiber in the diet is linked with a 10 percent lower risk of colorectal cancer, according to an analysis of studies in the Continuous Updates Project of the American Institute for Cancer Research (AICR) and World Cancer Research Fund. High-fiber diets encourage the growth of health-promoting gut bacteria, which use fiber to produce substances (like butyrate) that protect colon cells against cancer and may have anti-inflammatory effects. What’s more, fiber adds bulk and reduces the time your digestive tract is exposed to carcinogens.
Tips: Foods with fermentable fibers may be important to get the protective substances gut bacteria produce, according to Lampe. Examples include beans, oats, barley, and many fruits and vegetables. But since fiber’s protection seems to come through many paths, aim for a variety of high-fiber foods from whole plant foods.
Combine uncooked oats with plain yogurt, nuts, and fresh or dried fruits, and let it sit overnight in the fridge to make muesli.
Add beans, lentils and tofu to soups, stews and stir-fries.
2. Fill Up on Plants. Mediterranean diets, anti-inflammatory diets, and diets scoring high on the Healthy Eating Index (indicating a good fit with the Dietary Guidelines for Americans) are all linked to lower risk of colorectal cancer. These eating habits are centered around plant foods, like vegetables, fruits, whole grains, beans, and nuts.
Tips: Look beyond fiber content, emphasizes Lampe. “There are likely a lot of other aspects of diet-microbe interactions besides fiber that are important for cancer risk.” Many phytochemicals or compounds formed from them seem to support antioxidant, anti-carcinogen, or anti-inflammatory defenses.
- Let vegetables be the star in stir-fries and casseroles.
- Make a modest portion of cereal or yogurt more satisfying by filling at least half the bowl with fruit.
3. Be Choosy about Meat. When it comes to meat, the greatest colon cancer risk relates to processed meats (see page 3 Processed Meats, Risky Business), such as bacon, ham, sausage, and hot dogs. Limit consumption of meats preserved by smoking, curing, salting or the addition of chemical preservatives to very occasional use only. Eating too much red meat (beef, lamb, and pork) also raises risk, so AICR recommends holding it to no more than 18 ounces a week.
Tips: Choosing lean meats helps cut calories, but doesn’t remove the colon cancer risk, which seems tied to compounds formed in processing meat and after consuming it, and the effects of meat protein on inflammatory gut bacteria.
Replace meat with fish or seafood a couple of times per week to boost anti-inflammatory omega-3 fats and other healthful nutrients.
Add a few more meatless meals to your week.
4. Balance Calories In and Out. Colon cancer is among the 11 types of cancer linked to overweight and obesity, which promote inflammation and raise cancer-related growth factors and hormones. Physical activity seems to act through weight control assistance and more directly to guard against colon cancer.
Tips: Set realistic goals, since even a 5-10 percent weight loss can reduce levels of inflammation and cancer-related hormones.
If exercise seems overwhelming, set aside two or three 10-15 minute/week blocks for brisk walking.
Cut 250-500 calories a day by removing sugary drinks or other low-nutrient processed foods (such as cookies and doughnuts) from your diet.
Thomson emphasizes, “Any one food is unlikely to significantly cut inflammation. It’s the combination of total choices that is likely protective.” So as you cut calories, you can shape eating habits that defend against colon cancer on many fronts
—Karen Collins, MS, RDN, CDN, FAND