Diarrhea After Radiation

Radiation therapy uses high-energy x-rays to damage the DNA of cells. This kills cancer cells or stops them from reproducing. Radiation treatment can also cause harm to healthy cells in the area being treated. 

When the bowel is in the treatment area, this damage can lead to diarrhea, incontinence (not being able to hold your bowels), and urgency (needing to go right away). Your body may not be able to absorb the nutrients it needs from food. You may lose weight. These bowel issues are called radiation enteritis. It can happen months to years after radiation treatment and can be a long-term problem.

Tell your healthcare provider if you are having frequent diarrhea after having had radiation. Your provider can:

• Find out if there is some other cause for diarrhea.
• Find out if your blood has low levels of vitamins, such as B12.
• Order medications to help you have less diarrhea.
• Have you meet with a dietitian, who can help you handle your symptoms by making changes in your diet.

Keeping a Food Diary

If you are having diarrhea after radiation, it is a good idea to keep a food diary. This will help to see if certain foods cause diarrhea or make it worse. Your healthcare provider or dietitian will use this information to make suggestions.

• Write down the day and time of each meal or snack.
• Make note of what was eaten, how much, and the ingredients.
• Note any diarrhea or other symptoms you have. Write down as many details as you can.
• Keep this log for at least a week, as it can take time to find a pattern.
• Include any medications (prescribed or over-the-counter), vitamins or supplements you take in your log.
• Keep your log as you make a change in food or add a medication. Try to only make one change at a time to see how it affects your symptoms.

What can I do to stop or lessen the diarrhea?

• Take a fiber supplement, such as Metamucil (psyllium), Benefiber, or Citrucel. There are store brand versions of these products, which may cost less.
• Eat bland and easy-to-digest foods such as chicken, fish, eggs, puddings, mashed potatoes, noodles, rice, yogurt, cottage cheese, cream of wheat, farina, smooth peanut butter, white bread, bananas, applesauce, canned fruit, and well-cooked vegetables.
• Soluble fiber is a type of fiber found in some foods that soak up fluid and can help ease diarrhea. Foods high in soluble fiber are:
  • Fruits: Applesauce, bananas (ripe), canned fruit, orange, and grapefruit.
  • Vegetables: Boiled potatoes.
  • Breads & pastas: White rice and products made with white flour.
  • Cereals: Oatmeal, cream of rice, cream of wheat and farina.
• Eat small amounts of food 5-6 times throughout the day, instead of three large meals.
• Drink 8-10 glasses of non-caffeinated fluid per day. Other than water, you can try fluids that replace minerals and electrolytes lost through diarrhea, such as sport drinks (Gatorade®) or broth.
• Rice congee is a soupy rice that can help lessen diarrhea. To make it, mix 1 cup long or short-grain white rice with 6-7 cups of water or broth and one teaspoon of salt; bring to a boil, then simmer for about 40 minutes - until you have a sticky, soupy mixture.

Yogurt and Kefir may be helpful, but if you are lactose intolerant you should avoid dairy. 

What should I avoid if I have diarrhea?

• Avoid dried fruits, cruciferous vegetables (broccoli, cauliflower, cabbage, peas), raw vegetables, whole grains, beans, and legumes.
• Avoid caffeine (cola, coffee, tea), alcohol, milk or milk products, chocolate, dried fruits, beans, or popcorn, as well as fatty, fried, greasy, or spicy foods.
• Avoid very hot and cold drinks.
• Avoid sugar free gum, candy, and foods that have sorbitol, mannitol, or xylitol.

If you are having problems with diarrhea after radiation, make sure to speak with your provider.