Practical Tips: Foods to support your microbiome during treatment

Our bodies host trillions of microorganisms, primarily in our gut. In fact, they outnumber our own body’s cells! These guests make up what is called our “Microbiome”. When these microorganisms are in a healthy balance, they support many of our body’s functions such as intestinal wall integrity, metabolism, optimal immunity, inflammation control, brain and nervous system health and mood function. 

Chemotherapy can disrupt the gut microbiome, which can affect treatment outcomes ¹Chrysostomou, D., Roberts, L. A., Marchesi, J. R., & Kinross, J. M. (2023). Gut Microbiota Modulation of Efficacy and Toxicity of Cancer Chemotherapy and Immunotherapy. Gastroenterology, 164(2), 198–213.; Montassier, E., Gastinne, T., Vangay, P., Al-Ghalith, G. A., Bruley des Varannes, S., Massart, S., Moreau, P., Potel, G., de La Cochetière, M. F., Batard, E., & Knights, D. (2015). Chemotherapy-driven dysbiosis in the intestinal microbiome. Alimentary pharmacology & therapeutics, 42(5), 515–528.. Radiation to the abdominal or pelvic area can damage the lining of the gut and alter the microbiome ²Hauer-Jensen, M., Wang, J., & Boerma, M. (2014). Radiation-induced gastrointestinal toxicity: Mechanisms and clinical implications. Radiotherapy and Oncology, 112(1), 11–17.; Oh B, Eade T, Lamoury G, Carroll S, Morgia M, Kneebone A, Hruby G, Stevens M, Boyle F, Clarke S, Corless B, Molloy M, Rosenthal D, Back M. The Gut Microbiome and Gastrointestinal Toxicities in Pelvic Radiation Therapy: A Clinical Review. Cancers (Basel). 2021 May 13;13(10):2353. A growing body of evidence suggests that the microbiome influences the effectiveness of immunotherapy treatments. Certain microbes are associated with improved responses, though the research is complex, making it difficult to make general recommendations. ³Fuller-Shavel N, Krell J. Integrative Oncology Approaches to Supporting Immune Checkpoint Inhibitor Treatment of Solid Tumours. Curr Oncol Rep. 2024;26(2):164-174. doi:10.1007/s11912-023-01492-4; Routy, B., Le Chatelier, E., Derosa, L., Duong, C. P. M., Alou, M. T., Daillère, R., Fluckiger, A., Messaoudene, M., Rauber, C., Roberti, M. P., Fidelle, M., Flament, C., Poirier-Colame, V., Opolon, P., Klein, C., Iribarren, K., Mondragón, L., Jacquelot, N., Qu, B., Ferrere, G., … Zitvogel, L. (2018). Gut microbiome influences efficacy of PD-1-based immunotherapy against epithelial tumors. Science (New York, N.Y.), 359(6371), 91–97.; Gopalakrishnan, V., Spencer, C. N., Nezi, L., Reuben, A., Andrews, M. C., Karpinets, T. V., Prieto, P. A., Vicente, D., Hoffman, K., Wei, S. C., Cogdill, A. P., Zhao, L., Hudgens, C. W., Hutchinson, D. S., Manzo, T., Petaccia de Macedo, M., Cotechini, T., Kumar, T., Chen, W. S., Reddy, S. M., … Wargo, J. A. (2018). Gut microbiome modulates response to anti-PD-1 immunotherapy in melanoma patients. Science (New York, N.Y.), 359(6371), 97–103.  

One of the main ways we can support our microbiome is through our diet.

Strategies to support your microbiome during treatment

1. High fiber diet 
   Consuming whole grains, leafy greens, fruits, vegetables, legumes, and nuts support a diverse microbiome, and feed beneficial gut bacteria.
   • Microorganisms in your gut ferment the fiber you feed them and make a helpful substance called butyrateButyrate is produced when “good” bacteria in your gut help your body break down dietary fiber in your large intestine (colon). It’s one of several short-chain fatty acids, which are named for their chemical structure., which becomes their key energy source. Butyrate also improves the health of the GI tract by decreasing inflammation, protecting the barrier lining of the intestines, promoting a healthy microbiome and protecting against cancers such as colon cancer, and more. ⁴Hodgkinson, K., El Abbar, F., Dobranowski, P., Manoogian, J., Butcher, J., Figeys, D., Mack, D., & Stintzi, A. (2023). Butyrate’s role in human health and the current progress towards its clinical application to treat gastrointestinal disease. Clinical nutrition (Edinburgh, Scotland), 42(2), 61–75. 
   • Specific foods to help with butyrate production include,
     • Whole grains: oatmeal, brown rice, quinoa,  whole wheat
     • Legumes: beans, lentils, chickpeas
     • Fruits: high-pectin fruits such as apples, berries
     • Vegetables: garlic, onions, carrots, leafy greens, cruciferous vegetables such as broccoli, and cooked and cooled potatoes (high in resistant starcha type of carbohydrate that is not digested in the small intestine but instead ferments in the large intestine.)
     • Nuts and seeds: flax and chia seeds, almonds, walnuts, peanuts
     • Full-fat dairy products in moderation: yogurt, butter, cheese, ghee and milk 
2. Fermented foods 
   Deliver probiotics safely to the gut, creating a healthy and diverse microbiome. Fermentation also enhances digestibility and generates additional nutrients, such as vitamins and antioxidants. Other health benefits include a reduced risk of cardiovascular disease, diabetes, and obesity. ⁵Leeuwendaal, N. K., Stanton, C., O’Toole, P. W., & Beresford, T. P. (2022). Fermented Foods, Health and the Gut Microbiome. Nutrients, 14(7), 1527.
   • Examples of fermented foodsFood fermentation is the process of creating food or changing the properties of food using microbes.:
     • Yogurt 
     • Tempeh
     • Miso
     • Pickled vegetables, kimchi, sauerkraut (naturally fermented) 
     • Kefir 
     • Kombucha 
     • Sour cream 
     • Apple Cider Vinegar
   • Note, if you have a weakened immune system, avoid:
     • Cheeses and yogurts made with raw/unpasteurized dairy products
     • Unpasteurized drinks such as unpasteurized kombucha or raw milk;  
     • Check with your oncologist or oncology dietician to see if unpasteurized foods or beverages are safe for you.
3. Prebiotics
   Stimulate the growth of beneficial bacteria and promote the production of short-chain fatty acids (SCFAs) like butyrate, which have evidence for supporting beneficial bacteria.It has become common for the food industry to add prebiotic supplements like Inulin, to prepared beverages or snacks. However, the best (and tastiest) source of prebiotics comes from real food:
   • Garlic
   • Onions
   • Bananas
   • Whole oats
   • Apples
   • Dandelion greens.  
4. Probiotics 
   Probiotic supplements introduce beneficial bacteria to the gut, but choosing the right probiotic can be complex. The strain of the microbe matters. Whether and which probiotic to use is best guided by your physician, as conditions like low immunity may increase the risk for complications.
   
   Find an integrative practitioner to explore a personal probiotic regimen 

Read our side effect guides if you are experiencing digestive symptoms