Cancer Treatment, Side Effects, and Implications on the GI Tract

Cancer Treatment, Side Effects, and Implications on the GI Tract

Published on Monday, January 02, 2023 by Emily Hamm

A diagnosis of cancer is tough enough by itself. 

If any of you have had or currently have cancer and are undergoing any form of cancer treatment, you know how challenging some of the side effects can be on top of a heavy diagnosis.

I currently practice nutrition therapy in the oncology setting and I see people daily who struggle with the side effects related to treatment. Dietitians can help tremendously with side effect management through nutrition along with medication management. Let’s elaborate.

Common treatments for cancer include:

-          Chemotherapy/Immunotherapy

-          Radiation therapy

-          Surgery

Upper GI Side Effects and Solutions


Dry mouth and thick saliva

  • Increase hydration 
  • Limit/avoid caffeine and alcohol
  • Eat soft and moist foods (for example: add broth, gravy, and sauces to meals)
  • Suck on hard candy, frozen fruit, ice chips, and cold foods
  • Practice good oral hygiene (avoid alcohol-containing mouth care products; choose products such as Biotene instead)
  • Rinse your mouth with a baking soda and salt rinse several times daily (3/4 tsp salt, 1 tsp baking soda, 1 qt warm water)
  • Sleep with a cool mist humidifier
  • Swish and spit with club soda to loosen up thick secretions

Taste changes

  • Rinse mouth with a baking soda and salt rinse several times daily (3/4 tsp salt, 1 tsp baking soda, 1 qt warm water)
  • Avoid metal utensils and canned foods- use plastic or bamboo utensils instead
  • Use a variety of seasonings/sauces to alter the taste of foods
  • Try M Berry supplements or MetaQil

Difficult and painful swallowing

  • Try a texture-modified diet- soft/liquid foods
  • Request a magic mouthwash prescription to numb your throat
  • If unable to swallow or choking, talk with your medical team about the possibility of a feeding tube (most of the time this is short-term)
  • If you have mouth/throat sores,  talk with your medical team about using L-glutamine to help heal and prevent them from coming back

Lower GI Side Effects and Solutions


Abdominal pain/cramping

  • Avoid foods that trigger abdominal pain- (for example sugary foods, high-fat foods, fried foods, and foods high in insoluble fiber)


  • Increase fiber in your diet
  • Increase hydration
  • Try drinking prune juice or eating prunes
  • Use psyllium fiber supplement
  • Talk with your provider to see about taking a probiotic supplement
  • Consume a hot beverage to stimulate your bowels
  • Engage in light activity or stretching


  • Increase soluble fiber foods (bananas, applesauce, oatmeal, rice, pasta, cooked carrots, squash, peaches, oranges, avocados)
  • Increase hydration- use electrolyte-rich beverages
  • Avoid caffeine, alcohol, and carbonated beverages
  • Avoid gas-forming foods and insoluble fiber foods (broccoli, Brussels sprouts, cabbage, cauliflower, corn, onions, peppers, peas)
  • Avoid fried foods, high-fat foods, high-sugar foods
  • Avoid sorbitol, xylitol, mannitol, and other sugar-alcohols
  • Try supplements like L-glutamine to help prevent and treat colitis
If you or a loved one is going through cancer treatment, you can view this list to find a Board Certified Specialist in Oncology Nutrition in your state. Also, check out the American Institute for Cancer Research and the American Cancer Society for more information.


  1. Richards, J., Arensberg, M. B., Thomas, S., Kerr, K. W., Hegazi, R., & Bastasch, M. (2020). Impact of early incorporation of nutrition interventions as a component of cancer therapy in adults: A Review. Nutrients, 12(11), 3403.
  2. Voss, C. A., & Williams, V. (2021). Oncology nutrition for clinical practice. Academy of Nutrition and Dietetics.

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