Tips for Managing Diarrhea after Radiation Therapy for Rectal Cancer

Tips for Managing Diarrhea after Radiation Therapy for Rectal Cancer



Do you have diet suggestions for someone who has diarrhea after radiation therapy for rectal cancer? 


Chronic radiation enteritis is the technical term for the long-term damage that can result after radiation therapy for rectal cancer. It can lead to chronic diarrhea, incontinence, and bowel urgency. This can occur after treatment of other cancers that require radiation therapy to the abdominal area as well. These side effects can occur months, or even years, after therapy is completed.

The following suggestions can help you manage chronic diarrhea:

  • If this is a new symptom, tell your doctor about it. Your doctor can help determine if a treatable medical condition is contributing to the diarrhea, and prescribe medications to manage it, if appropriate
  • Ask your doctor to check you for "C. diff" (Clostridium difficile) infection. C. diff is an overgrowth of normal GI bacteria, and can cause severe loose stools and abdominal cramping
  • Drink at least three quarts (12 cups) of liquid each day to prevent dehydration. Drink liquids at room temperature and sip them slowly throughout the day. Avoid drinking large quantities at once, and avoid sugary beverages such as juice and regular soda. These can worsen diarrhea. Try plain broth or bouillon, Gatorade, decaf coffee, decaf tea and water. Avoid alcohol and caffeine
  • Eat small, frequent meals and snacks to avoid giving your digestive tract too much food at one time. Lie down immediately after eating
  • Keep a detailed food record of what you eat and drink. The foods that cause symptoms are different for each person. Record what and how much is eaten, whether foods are homemade or from a restaurant, food temperature, and time of day. Include specific details about the symptoms you experience. Discuss the food and symptom diary with your Registered Dietitian Nutritionist (RDN), who can help you determine what triggers symptoms. It may take several weeks to identify patterns, so be patient!
  • Review all complementary and alternative therapies you are using, such as special teas, vitamins, minerals, herbal supplements, and other nutrients, with your RDN. Some herbs and dietary supplements can cause diarrhea
  • Discuss diarrhea medication options with your doctor. Imodium or other anti-diarrheal medications may allow for a less restrictive with diet
  • Supplement your diet with psyllium, guar gum, inulin, or another soluble fiber product as soon as possible. If you can, add a fiber supplement when you begin radiation therapy. Begin with one dose per day, per package instructions. Increase
  • Change only one aspect of your treatment at a time. For example, change your diarrhea medication or your food intake, but not both at once. This will let you evaluate what works and what doesn't
  • Snack on dry, salty foods, such as saltine crackers or dry toast 
  • Avoid hard-to-digest foods, such as popcorn, peas, corn, raw vegetables, and “gassy” vegetables in the cruciferous and allium vegetable families. This includes broccoli, cauliflower, cabbage, Brussels sprouts, kale, chard, onions, garlic, and leeks 
  • Avoid spicy foods if they worsen your diarrhea
  • Avoid sugar-free foods and gum, and candy made with sugar alcohols, such as sorbitol, mannitol, and xylitol. Sugar alcohols can worsen diarrhea. Also avoid tobacco (cigarettes, pipe or chewing tobacco), which can aggravate diarrhea
  • Avoid greasy, fatty and fried foods, such as French fries, bacon, sausage, pizza, cheese, pastries, snack chips, gravies, high-fat sauces and salad dressings
  • Eat yogurt with live active cultures or drink buttermilk or kefir. Aim for 4-8 ounces daily. Use other dairy products only if you’re taking lactase tablets to aid digestion. Try non-dairy milk, such as soy, rice, or almond, in place of cow’s milk
  • Eat more foods with soluble fiber, including oatmeal or oat bran, bananas, applesauce, and canned peaches and pears. Beans are high in soluble fiber, but can cause gas and worsen symptoms. Avoid these as much as possible
  • Avoid foods with insoluble fiber, including fresh fruit and raw vegetables, and whole grain breads and cereals. Eat well-cooked, peeled fruits and vegetables or consider adding them to soups or smoothies. This breaks down the insoluble fiber, making it easier to digest
  • Try Rice Congee, a soupy rice mixture. Combine 1 cup long or shortgrain WHITE rice with 6-7 cups of water and one teaspoon of salt; bring to a boil, then simmer until you have a sticky, soupy mixture (usually ~ 40 minutes). Sip and eat mixture. Broth may be used instead of water
  • Ask your dietitian if you need a vitamin and mineral supplement to help make up for malabsorption due to diarrhea. A chewable product, with 100% of the daily value (DV) for most vitamins and minerals can be taken twice daily. As diarrhea improves, switch to once daily dosing
  • Ask your doctor or dietitian to order blood tests for vitamin B12 and fat-soluble vitamins. You may need to provide a stool sample, as well, so you can be checked for bile salt malabsorption
  • Ask your doctor or dietitian about testing for undiagnosed celiac disease (gluten intolerance). You must eat a 100% gluten-free diet to manage celiac disease if you are diagnosed with this condition. Seek counseling from an RDN to help you design a healthy, well-balanced, gluten- free diet

The original question and answer were generously donated by Diana Dyer, MS, RD a cancer survivor, registered dietitian, organic garlic farmer, and the author of "A Dietitian's Cancer Story: Information & Inspiration for Recovery & Healing from a 3-time Cancer Survivor."

Question and Answer updated on behalf on the ON DPG by Jennifer McIver, R.D., April 2013, Daria Pori, April 2016

Page Updated: April 2016