Foods You Should Eat to Avoid Colon Cancer

Anything that starts out growing in the ground gets the green light for your diet. That includes fresh fruits and vegetables, legumes (beans), whole grains, nuts, and seeds. “These foods contain antioxidants—chemicals that help eliminate oxygen-free radicals associated with cancerous changes—and unique fibers that can both trap carcinogenic material and promote cellular defense mechanisms,” explains Bethany Doerfler, R.D.N., registered dietitian in the division of gastroenterology and hepatology at Northwestern University Feinberg School of Medicine in Chicago.

Eating a plant-based diet doesn’t mean you have to be a vegetarian. You do, however, want to give meat, especially red meat, the back seat behind plant foods. That includes basically anything that originally had four legs: beef, veal, lamb, pork, and goat. “Red meat contains heme (iron) compounds that can damage the lining of the gut,” Taylor says. Plus, the by-products of digesting red meat are dangerous to the DNA of the colon cell, Doerfler notes. To be safe, eat no more than three servings of about 4 ounces each of red meat per week.

That includes bacon, ham, sausage, hot dogs, jerky, bratwurst, kielbasa, and lunch meats like deli turkey, bologna, pastrami, and corned beef. (Yes, you may have to start rethinking your lunch.) Eating only 1.8 oz.—that’s two strips of bacon—of processed meat per day increases your risk of colorectal cancer by 16%, Taylor says. In addition to the other issues with red meat, which much of this processed category comes from, the preservatives in processed meat may lead to cancer-causing compounds forming in the body, she notes. Make bacon a special-occasions-only treat.

High-fiber foods are a win-win for multiple reasons, says Taylor. For starters, fiber increases the bulk and weight of stool, diluting harmful substances. It then speeds the elimination of those harmful substances from the body, protecting the lining of the colon. Fiber also helps control body weight by slowing digestion and keeping you fuller, longer—important since excess body fat increases colon cancer risk—and helps produce a fatty acid that may play a role in decreasing risk. Aim to get at least 30 grams of fiber a day.

In addition to providing fiber, fruits and vegetables also contain phytochemicals, compounds that inhibit cancer growth and boost immunity. You can identify the phytochemical by the color of the food. Dark greens, like spinach, kale, and broccoli, contain isothiocyanates, which have been associated with a lower risk for cancer. Red fruits and veggies like tomatoes, red peppers, and watermelon contain lycopene, which also may be cancer-protective. Yellow or orange foods like carrots, sweet potatoes, and pumpkin feature cancer-preventing carotenoids. Aim for at least five and ideally nine servings daily.

Resistant starch is a kind of fiber found in potatoes, legumes like beans and lentils, and a variety of whole grains like oats and barley. “Our bodies can’t digest resistant starch, so our gut bacteria converts it into the compound butyrate, which studies suggest protects against cancer,” explains Taylor. It may be especially helpful to eat resistant starch when you treat yourself to that occasional red meat. Some research suggests that eating them together appears to decrease the production of cancer-causing compounds associated with the meat. So sometimes, eating meat and potatoes can be a good thing!

“More whole grains equals more cancer protection,” Taylor emphasizes. Unfortunately, on average, Americans eat only 10 grams of whole grains daily—just one third of the recommended amount. “Three servings a day (90 grams) is associated with a 17 percent decreased risk for colorectal cancer,” she says. That’s because whole-grain foods contain anti-cancer vitamins and phytonutrients, help reduce chronic inflammation, and protect the gut from carcinogens by speeding up transit (read: poop) time.

It would be great if there were a magic pill that delivered the cancer-preventing nutrients you need, but no such luck—no matter what supplement marketers may claim. “The natural food matrix of vitamins, minerals, antioxidants, and fiber produces beneficial effects on the gut which are more protective than what supplements can deliver,” Doerfler says. Also, the isolated nutrients in supplements appear to be less well-absorbed. An exception: Vitamin D, which has been associated with a lower risk of colorectal cancer but is hard to get in foods. For D, a supplement may be helpful.

Let’s get the bad news out of the way first: Alcohol is not a great idea, because it contains cancer-causing agents that damage DNA. “Consuming 3.5 drinks per day was associated with a 50 percent increased risk of colorectal cancer compared to light or non-drinkers,” Taylor warns. “Avoid it entirely or limit yourself to less than two drinks a day.” Watch out for sugary drinks (sodas, fruit juices, sports drinks), as well, because they can lead to excess body fat, a major risk factor for colorectal cancer as well as 11 other types of cancer.

Meanwhile, much-loved energy boosters coffee and tea get the thumbs up when it comes to colon cancer prevention, although more research is needed. Coffee contains phytochemical compounds that reduce cancer cell growth, block carcinogens, and promote cancer cell death, Taylor says. Tea has similar phytochemical compounds, and a large-scale Chinese study found that drinking two to three cups of tea per week decreased digestive cancers by about 14%. Two to three cups of tea daily brought that protection to 21%, and long-term (20 years or more) tea drinkers had a 29% reduced risk.