Does nutrition play a role in cancer patients receiving immunotherapy treatment?
The good news is that cancer is no longer necessarily a death sentence. (1) Currently, one of the main areas of cancer research is immunotherapy, a treatment that harnesses the power of our immune system to identify and control diseases such as cancer. This treatment has allowed more than 15.5 million people to live beyond a cancer diagnosis as of 2016 – and this number is expected to surpass 20 million by 2026. (1) Immunotherapy can be administered intravenously, orally, topically, or by intravesical treatment, and is either dispensed from or administered at doctors’ rooms, a clinic or an out-patient unit in a hospital.(8)
Immunotherapy has greatly improved cancer outcomes, yet variability in response and off-target tissue damage can occur with these treatments, including immune checkpoint inhibitors (ICIs). Multiple lines of evidence indicate the host microbiome influences ICI response and risk of immune-related adverse events (irAEs). As the microbiome is modifiable, these advances indicate the potential to manipulate microbiome components to increase ICI success.(2)
The composition of the gut microbiome may contribute to the efficacy of cancer therapy, primarily by modulating the antitumour immune response through training infiltrating myeloid and APCs in distant tumours. This was shown in a series of studies involving CpG-oligodeoxynucleotides, oxaliplatin, cyclophosphamide, activated clotting time (ACT) and immune checkpoint inhibitors. Until recently, most data was from mouse models but several clinical studies have now suggested a role of microbiota composition in response to treatment, including anti-PD-1 therapy.(3)
Dietary patterns and gut microbiome
Specific dietary patterns, such as animal-based, vegetarian, or Mediterranean diets, for example, alter the gut microbiome’s composition.(4) An appropriate intestinal microbiota structure might modulate the function of the human immune system, which affects the body’s anti-cancer response.
- Mediterranean Diet:
A Mediterranean diet, containing mono-and polyunsaturated fats from olive oil, nuts and fish, polyphenols and fibre from vegetables, fruit, and wholegrains, was significantly associated with an improved response to ICIs. ICIs have been highly successful in treating melanoma, and work by blocking immune system checkpoints, which then force the body's own T-cells to attack cancers.(4)
Fasting every other day leads to increased levels of Firmicutes inside the gut while simultaneously lowering the amounts of other phyla (5). Different forms of fasting, such as intermittent fasting, multi-day fasting and diets that mimic fasting, improve intestinal microbiome diversity.(4)
- Low-FODMAP diet:
A low-FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) diet is considered beneficial because total bacteria levels, as well as the amounts of specific bacteria, like Bacteroides, Clostridium coccoides, Enterococcus, Eubacterium rectale, Faecalibacter prausnitzii, Lactobacillus, and Prevotella, are not affected by the diet. (6,7) Subjects who followed a low-FODMAP diet for three weeks, besides a decreased amount of Bifidobacteria, showed elevated levels of Actinobacteria and Lachnospiraceae, as well as generally increased diversity. In addition, the subjects had increased levels of Firmicutes, Clostridiales, and overall microbiotic diversity. However, long-term use of a low-FODMAP diet is problematic due to the limited amount of healthy plant foods and natural probiotics. (7)
As good gut health promotes the efficacy of immunotherapy, dietary interventions that can positively alter a patient’s gut microbiota are recommended. As Immunotherapy is more effective when combined with good gut health, the role of nutrition, therefore, cannot be understated. Moreover, diet may have other beneficial effects not mediated by the microbiome. Dietary intervention based on promoting a wholefood, plant-based high-fibre diet may be more cost-effective and acceptable and provide wider health benefits than approaches solely based on microbiome modulation.
- Johns Hopkins in Health – Immunotherapy: Precision Medicine In Action https://www.hopkinsmedicine.org/inhealth/about-us/immunotherapy-precision-medicine-action-policy-brief.html#:~:text=Immunotherapy%20drugs%20work%20better%20in,are%20about%2015%20to%2020%25
- Gopalakrishnan V, Spencer CN, Nezi L, et al. Gut microbiome modulates response to anti-PD-1 immunotherapy in melanoma patients. Science 2018;359:97–103.
- MDPI: Diet, Microbiome, and Cancer Immunotherapy—A Comprehensive Review. https://www.mdpi.com/2072-6643/13/7/2217
- Klement, R.; Pazienza, V. Impact of Different Types of Diet on Gut Microbiota Profiles and Cancer Prevention and Treatment. Medicina 2019, 55, 84. [Google Scholar] [CrossRef] [PubMed][Green Version]
- Hills, J.R.D., Jr.; Pontefract, B.A.; Mishcon, H.R.; Black, C.A.; Sutton, S.C.; Theberge, C.R. Gut Microbiome: Profound Implications for Diet and Disease. Nutrients 2019, 11, 1613. [Google Scholar] [CrossRef][Green Version]
- Reddel, S.; Putignani, L.; Del Chierico, F. The Impact of Low-FODMAPs, Gluten-Free, and Ketogenic Diets on Gut Microbiota Modulation in Pathological Conditions. Nutrients 2019, 11, 373. [Google Scholar] [CrossRef][Green Version]
- National Cancer Institute (Immunotherapy to Treat Cancer): https://www.cancer.gov/about-cancer/treatment/types/immunotherapy#how-is-immunotherapy-given