By Dena McDowell, MS, RD

Whether you are undergoing radiation therapy, chemotherapy, or a combination of the two, cancer treatment often causes gastrointestinal problems. Pain medications, dehydration, and changes in diet often slow the bowels and cause constipation; whereas certain types of chemotherapy and radiation therapy to the pelvic region cause diarrhea. Bowel issues can be alleviated with specific diets, proper hydration, and in certain instances, prescription medications.

Bowel issues can be regulated with a proper diet. Constipation and diarrhea are very common side effects of cancer treatment, so do not be embarrassed if you suffer from either. It is important to inform your health care team if you are experiencing any of these symptoms; they can help with dietary and medical interventions. Here are some general recommendations to help with your symptoms.

Alleviating constipation during cancer treatment

When dealing with constipation, examine your diet and hydration levels. The goal is to normalize your bowel movements through diet and medications as needed. To promote this, it is important to eat at about the same time each day and to incorporate the same amount of fiber and hydration in your diet.

Start the day with a large breakfast. Eating a fiber-rich cereal (bran-based or oatmeal), fruit, and a hot beverage (coffee or tea) can jump-start your gastrointestinal tract. Prune juice and stewed prunes also stimulate the colon.

For lunch and dinner, include raw fruits and vegetables with each meal. Whole grain bread, pasta, and rice can also increase the fiber in your diet. Beans or legumes are a good source of fiber. To prevent gas and bloating, gradually add them to your diet.

When you increase the fiber in your diet, it is important to drink enough fluids. Water, sports beverages, juice, and hot beverages all work well. Try to drink a minimum of 8 to 10 cups of liquid a day. Avoid foods such as white rice, bananas, and cheese if you are constipated.

Pain medications cause constipation, so if diet and hydration do not work, speak to your health care provider for a prescription for a laxative or stool softener.

Controlling diarrhea during cancer treatment

If you are undergoing chemotherapy or radiation to the pelvic region, you may have the opposite bowel issues. If diarrhea is a problem, a special low residue diet is usually helpful in slowing down stool production. A low residue diet consists of limiting dairy, greasy high fat foods, and high fiber foods. Foods to avoid include:

• Dried beans, peas, and lentils
• Nuts and seeds
• Whole grain breads, cereals, and pastas
• Wild or brown rice
• Fresh or unpeeled fruit
• Coconut
• Dried fruits
• Fresh vegetables
• Pickles
• Popcorn
• Fatty meats
• Spicy and highly seasoned foods
• Large quantities of milk (more than 2 cups per day) and dairy products
• Sorbitol (the artificial sweetener found in sugar free gums and candies).

When dealing with diarrhea, drink enough fluids to stay hydrated. Consume diluted fruit juices, water, sports drinks, and broths throughout the day. A good rule of thumb is to drink at least 1 cup of fluid after each loose bowel movement. To reestablish your electrolyte balance, add foods that are rich in sodium and potassium in your diet, such as broth soups, sports drinks, pretzels, crackers, skinless potatoes, cantaloupe, and bananas. Eating foods with pectin can also add bulk to stools. Try eating applesauce, rice, and bananas to increase pectin in your diet.

See your health care provider if your diarrhea is persistent or if you are unable to replenish the liquids in your diet. Your health care provider can prescribe medications that can alleviate the rate of stooling.