What to eat to prevent colon cancer

Kelsey Coulter, RD, CSO, is a registered dietitian and board-certified specialist in oncology at the Inova Saville Cancer Screening and Prevention Center and Survivorship Clinic.

Colorectal cancer screenings are the best way to prevent colorectal cancer and diagnose it early. A colonoscopy can detect and remove precancerous polyps and cancerous growths, providing both diagnosis and treatment in one procedure.

But there’s an additional way you can help prevent this cancer – and it starts in your kitchen. In fact, a combination of regular screenings and a colon-healthy diet could be the perfect recipe for reducing your risk.

The foundation: fiber

The most important dietary change you can make for better colon health is to increase your intake of high-fiber plant foods. The goal for most adults is 25 to 34 grams of fiber daily, depending on overall calorie needs. Only about 5% of U.S. adults reach this target.

Fiber can reduce your risk of colon cancer because it:

• Feeds beneficial gut microbes (bacteria and yeasts) that produce protective compounds like short-chain fatty acids
• Helps you feel fuller after meals, which supports a healthy body weight — a protective factor against colorectal cancer

Vegetables are cancer fighters

Vegetables, especially non-starchy types, can help lower your colon cancer risk. Not only do they contain fiber, but they also contain antioxidants. These compounds clean up free radicals, which cause cell damage that can lead to cancer. Veggies that are colorful or leafy are some of your best bets, such as:

• Artichokes
• Asparagus
• Broccoli, cauliflower and Brussels sprouts
• Celery
• Green beans
• Kale, spinach and other leafy greens
• Peppers
• Tomatoes

Easy ways to add more vegetables to your diet

If you’re not eating enough vegetables, try these strategies to help increase your intake:

• Change your preparation method: Raw cauliflower tastes different from roasted cauliflower with olive oil and garlic. If you think you don’t like a vegetable, try preparing it differently with seasonings you enjoy.
• Hide them: Blend vegetables into sauces, soups or smoothies so they’re not the main focus of the taste.
• Make it convenient: Keep frozen vegetables on hand. All the nutrients are still there, and they cut prep time dramatically. Canned options are convenient and nutritious, too.

The power players: beans, legumes and nuts

Beans, legumes and nuts are great for your colon. They add a punch of fiber, protein and other nutrients all in one package. You can add these foods to existing recipes or try them on their own. Ideas include:

• Adding black beans to tacos
• Cooking lentils into a meat sauce for pasta
• Eating hummus with fresh veggies instead of chips and dip
• Making a chickpea wrap for lunch instead of using lunch meat
• Snacking on ¼ cup of nuts with fruit instead of processed snacks
• Sprinkling nuts on salad or yogurt

Don’t forget whole grains

Another colon-healthy swap involves choosing whole grains over refined grains. Aim for at least half of your grains to be whole grains, though more is even better. Try these swaps:

• Air-popped popcorn (yes, it’s a whole grain) instead of crackers
• Quinoa or farro instead of white rice
• Whole-grain pasta or bread instead of white varieties

Other protective nutrients

While fiber takes center stage, other nutrients may also reduce colon cancer risk, including:

• Calcium, found in dairy products like low-fat milk and cottage cheese and some non-dairy alternatives like almond milk
• Omega-3 fatty acids, found in flaxseeds and fatty fish like salmon
• Vitamin C, found in bell peppers, broccoli, kiwis and citrus fruits
• Vitamin D, found in egg yolks and some fortified foods and milks

If you’re eating a balanced diet with plenty of plant foods, you’re likely already getting enough vitamin C and some omega-3s. However, because vitamin D is found in relatively few foods, talk to your provider about vitamin D supplementation and whether it’s best for you.

Foods to limit for colon health

The evidence is clear that red meat, processed meats and alcohol increase colon cancer risk. You don’t need to eliminate them entirely, but limiting them is wise:

• Aim for no more than 18 ounces of red meat weekly (about three small servings).
• Eat little, if any, processed meat, such as hot dogs, bacon, and sausage.
• Limit your alcohol intake to moderate amounts: no more than one drink daily for women and two for men. One standard drink is 5 ounces of wine, 12 ounces of beer or 1.5 ounces of liquor. Alcohol is a carcinogen that increases the risk for multiple cancer types.

If you do eat red meat, avoid cooking it at very high temperatures, such as grilling over an open flame. Cooking at high temperatures can produce potentially cancer-causing compounds in the meat. Instead, bake or roast at lower temperatures, remove any blackened bits and marinate meat before cooking.

It’s also helpful to cut back on highly processed foods and sugar-sweetened beverages. These options are low in nutrients and high in calories, and they tend to promote weight gain.

Building your colon-healthy plate

The American Institute for Cancer Research recommends the New American Plate. This guideline suggests that meals should include:

• Two-thirds plant foods, such asfruits, vegetables, whole grains and legumes
• One-third (or less) animal proteins, such as fish, poultry, eggs or meat

This approach is similar to the Mediterranean diet, which emphasizes plant foods while including fish and healthy fats like olive oil. The New American Plate and Mediterranean Diet are flexible and sustainable, shifting the proportions on your plate without requiring you to give up foods you enjoy.

Can supplements lower colon cancer risk?

Many people wonder if supplements can help prevent cancer. Right now, there’s no supplement with strong evidence showing it reduces colorectal cancer risk.

Get nutrients from food whenever possible. Whole foods contain a variety of nutrients that aren’t available in a pill. Take supplements only if you have significant dietary gaps or your doctor specifically recommends them.

Start small and focus on adding, not avoiding

Small changes add up, and you don’t need to overhaul your entire diet overnight. You can get started with colon-healthy changes by adding:

• One extra serving of fruits or vegetables each day
• Nuts or seeds to your oatmeal or smoothie
• Whole grains or legumes into one of your recipes

Aim for healthy food addition, rather than subtracting foods. When you add fiber-rich plant foods to your meals, they naturally help phase out some of the foods we want to eat less of. It’s a more positive, sustainable approach than focusing on restriction.

Your dietary choices are powerful tools in cancer prevention. By gradually incorporating more fiber-rich plants into your meals, you’re taking meaningful steps to reduce your risk of colon cancer, and you’re improving your overall health in the process.

Looking for more information about eating for cancer prevention? Join the free “Cooking with Kelsey” virtual class.