How cancer therapies affect the microbiome

The role your gut bacteria play in the response of your immune system has been most studied in the recent decade. Researchers however still have limited knowledge in understanding the full role microbes in our gut, or the gut microbiota, play on influencing the immune response. Oppositely, the health of our immune systems also impacts the concentration of healthy and harmful microbes in our gut.

Immunotherapy is an even more recent topic that offers cancer patients an alternate strategy for healing. Bacteria are responsible for communicating with the immune system so intrinsically that researchers have found that bacteria can be used to possibly cure cancer in immunotherapy. [5]

Today you can optimize the health of your immune system preventing illness and cancer today but maintaining a healthy gut microbiome.

Influences of gut microbes on immunity

A community of microorganisms inhabits the digestive tract making up the gut microbiota. Bacteria are the primary residents that colonize the intestines amongst the one hundred trillion organisms. Other inhabitants include fungus and viruses.

The healthy co-existence in a mutual relationship within the human body inhibits cancer growth and development. Healthy bacteria help coordinate chemotherapeutic pathways regulated by the immune system.

When it comes to cancer treatment, every individual has a different immune response controlled by several influences. For example, different cancer patients may exhibit different responses and reactions from the same chemotherapeutic drug. These factors include infection, metabolism, gut dysfunction including bacterial imbalance and the environment. [3] Promoting the healthiest conditions of bacteria in your gut increases anticancer activity response of the immune system by stimulating tissue repair and detoxification. [1]

Dr. David Jockers

“Despite your genetics and the predispositions you have to develop cancer, you can avoid the risk factors which disrupt immune responses and your ability to defend against infectious and cancerous agents.”

Dr. David Jockers

Bacteroidales and Bifidobacteria

Two common bacteria species are associated with a strong immune system. Bacteroidales and Bifidobacteria are the major classifications of bacteria reflected by the body’s ability to prevent cancer growth. Researchers at the University of Chicago found that these strains of bacteria in the gut actually reduce tumor growth similar to a new chemoprevention drug currently being tested in human trials. [7]

The drug used, ipilimumab, was used in the study to analyze the advantages of bacterial strains and was approved in 2011 for the treatment of melanoma cancer. Cancerous mice with normal gut bacteria were given ipilimumab and exhibited improved healing abilities such as a decrease in abdominal inflammation. Germ-free mice or those with antibiotic-treated systems did not exhibit the same health response. [5]

The study shows that the cancer treatment drug ipilimumab destroys Bacteroidales and Bifidobacteria while stimulating the immune response to attack and treat cancer. These results support the necessity to maintain a healthy gut microbiota.

Targeting CTLA-4

The protein CTLA-4 (cytotoxic T-lymphocyte-associated protein 4) is a key immune system regulating protein. The drug ipilimumab functions to block the CTLA-4 response which downregulates the immune system and functions as one of the primary treatments known as immune checkpoint blockade therapy. [6]

Patients who have these antibodies which serve as an antagonist and shut off CTLA-4 have antitumor effects. Ipilimumab functions as an antibody blocking the protein’s receptors but is reliant on Bacteroides species. Germ-free mice and those with antibiotic treatments did not have the capacity to block the receptors on CTLA-4 and thus did not exhibit anti-cancer effects. [4]

Avoid risk factors for gut dysbiosis

Maintaining a healthy gut microflora is essential for supporting a healthy immune response and optimal health and healing. Gut bacteria are key players in the elimination of toxinsA poison made by certain bacteria, plants, or animals, including insects. from the body and nutrient absorption. A diverse and healthy gut microbiota promotes an external immune response exhibited from the intestines to the health of your skin.

Free radical agents destroy the immune system while stimulating carcinogenesis, or the initiation of cancer formation. Beneficial bacteria are capable of inhibiting the release of these destructive and carcinogenic agents. [2]

Despite your genetics and the predispositions you have to develop cancer, you can avoid the risk factors which disrupt immune responses and your ability to defend against infectious and cancerous agents. Major influences include smoking, diet, and antibiotic treatment. Recall, the germ-free and antibiotic-treated mice did not possess the ability to treat cancer. These same mice in the study also had zero potential for tumor invasive lymphocytes to destroy cancer cells.

10 tips for maintaining a healthy gut microbiota

Leaky gut syndrome, colitis and other infections of the gut promote carcinogenic activity from bacteria. Optimizing healthy gut bacteria within your digestive tract is as simple as supporting healthy digestion.

The following list provides strategies for you to improve the conditions of your gut microbiota and promote anti-cancer properties that benefit the whole body: [1, 3, 8, 9]

  1. Take a once daily probiotic to improve health. Probiotics increase the transmit time for foot and toxins to pass through the body, therefore, stimulating regularity.
  2. Avoid all contaminants including sugar which deplete beneficial gut bacteria. Sugar feeds harmful gut bacteria while increasing inflammatory conditions.
  3. Consume anti-inflammatory foods rich in herbs and dark leafy greens that stimulate natural detoxification pathways and stabilize intestinal pH.
  4. Eat fresh, organic or vegetables containing no synthetic sprays. Farmers markets are excellent locations to find foods yet to be cleaned. These foods have soil-based microorganisms that will help reduce harmful bacterial overgrowth in the gut while stimulating digestive function and the immune response. (Note that this is not indicative of consuming vegetables covered in dirt and rather that a limited amount of dirt won’t harm you.)
  5. Avoid medication use and especially the use of antibiotics. Ampicillin and streptomycin are broad-spectrum antibiotics which deplete bacterial colonies and extinguish their anti-cancer benefits.
  6. Consume probiotic-rich foods that stimulate healthy bacteria growth. For instance, add foods like garlic, leeks, asparagus, jicama and onions into your diet daily.
  7. Eat fermented foods regularly. Adding fermented veggies like kimchi and sauerkraut to meals as well as drinking beverages like kefir and coconut water improve the microbiome. Also, consider adding small quantities of raw apple cider vinegar to water for its benefits.
  8. Add antioxidant-rich foods like berries to your diet. Berries contain powerful phenolic compounds that are broken down in the colon and stimulate detoxification pathways. Blackcurrant powder exhibits the same responses as prebiotics and stimulates Bifidobacteria Give your smoothies a chemopreventive boost by adding them to your beverages and even desserts.
  9. Consider intermittent fasting. Fasting for a minimum of 12 hours in a day can encourage enzymatic function and stimulate chemopreventive responses. While fasting, drink plenty of herbalA product made from a plant that is thought to be useful in treating a disease or staying healthy. Herbal supplements are taken by mouth. teas, water, and fermented drinks to promote gut function.
  10. Relax before eating. Eating on the go is not the best technique to optimize digestion. Doing so prevents adequate digestive juice secretions such as stomach acid, pancreatic enzymes, and bile. These conditions stress the digestive tract causing intestinal inflammation and promoting microbial overgrowth. Improve digestion before eating by taking three relaxing deep breaths. This helps you relax and improves digestion.

Optimize gut health for long-term health

You can focus on stimulating your digestive system and maintain healthy gut bacteria to prevent and heal from cancer. Gut microbes play an endless role in our body’s ability to metabolize food, absorb nutrients and successfully respond to cancer treatments- both conventional and alternative in nature. Follow the action steps listed in this article to help you improve your gut microflora and reduce your risk for a disease.


  1. Organic Lifestyle: How to Detoxify from Chemotherapy and Repair the Body Link Here
  2. Zitvogel L, et al. Cancer and the gut microbiota: An unexpected link. 2015. Sci Trans Med Jan; 7(271). Link Here
  3. Cario E. Toll-like receptors in the pathogenesis of chemotherapy-induced gastrointestinal toxicity. Curr Opin Support Palliat Care. 2016 Jun; 10(2): 157-64. PMID: 26986508
  4. Vetizou M, et al. Anticancer immunotherapy by CTLA-4 blockade relies on the gut microbiota. Science. 2015 Nov; 350(6264): 1079-1084. PMCID: 4721659
  5. New Scientist: Gut bacteria may affect the success of cancer treatments Link Here
  6. Perez-Chanona E, and Trinchieri G. The role of microbiota in cancer therapy. Curr Opin Immunol. 2016 Apr; 39: 75-81. PMID: 26820225
  7. Francois T, et al. Environmental and Gut Bacteroidtes: The Food Connection. Front Microbiol. 2011; 2: 93. PMCID: 3129010
  8. Afrin S, et al. Chemopreventive and Therapeutic Effects of Edible Berries: A Focus on Colon Cancer Prevention and Treatment. Molecules. 2016 Jan; 21(2): 169. PMID: 26840292
  9. Jaganathan SK, et al. Chemopreventive effect of apple and berry fruits against colon cancer. World J Gastroenterol. 2014 Dec; 20(45): 17029-17036. PMCID: 4258571