Research is increasingly showing the important role of the immune system in cancer. The World Cancer Research Fund recommends three main things that any person can do to reduce their risk or to help in their recovery. They are: be a healthy weight, exercise regularly, and eat a nutritious diet.[1] We have all heard this advice before, but may not have appreciated its link to cancer.
In our bodies, cancer cells develop regularly, especially as we grow older. A healthy immune system will provide continuous surveillance and destroy most aberrant cancer cells before they have a chance to grow and form a tumour.
Unfortunately, our modern-day lifestyle is not always conducive to maintaining optimal immune health. Many of us can face multiple stressors that can weaken our immune function, these can include factors such as smoking, poor dietary habits and nutrient depletion, damage to our microbiome, lack of exercise, increased levels of psychological stress and tension, alcohol consumption and exposure to toxic chemicals. These stressors, when sustained over long periods without resolution, can overburden the immune system and compromise its ability to deal with any circulating aberrant cells.[2][3]
For a cancer to be able to develop, it must be able to avoided detection by the immune system. Cancer cells become expert at doing this, and even enlist some of our normal cells to assist them. Cancer grows from what were originally healthy cells in our body, which over time, became increasingly damaged genetically and lost their original functions. The immune system can easily be misled into thinking the cancer cells belong there and because these now aberrant cells are not being recognized, they are not attacked and destroyed.
What makes it worse is that cancer can also hijack aspects of the immune system. It does so by a type of white blood cell that migrates into the tumour called “tumour-associated macrophages”. These macrophages produce chemicals which dampen the response of other immune cells whose job it is to kill the cancer.[4] They also send out chemicals that attract another type of cell that are called “regulatory cells,” which are designed to protect us from autoimmunity. But these regulatory cells can be used by the cancer to again protect it from the immune cells that would otherwise kill them, thereby providing an effective barrier to an anti-cancer immune response. [5]
It is important to note however, that the orchestration of the various different types of immune cells present within the tumour, as well as how they function, can be changed through altering the surrounding environment in which they reside. This can occur through various medical agents such as immunotherapy or through factors such as diet and microbiome health and lifestyle.[6]
Studies have showed us that having continually elevated high blood glucose levels can increase our risk of developing cancer and that many cancers use glucose as their main source of energy for to sustain their high rates of proliferation. Reducing the concentrations of glucose and other associated drivers of cancer growth (insulin/IGF-1) through dietary measures may help to sensitize tumour cells to conventional therapies and improve outcomes.[7]
The food we eat on a daily basis can provide the body with a wide array of natural substances that can help correct immune dysfunction. For example, fruits and vegetables, have a variety of important active compounds including vitamins, minerals, fibre, fatty acids and phytochemicals such as polyphenols, which can influence various chemical and inflammatory pathways. The many different types of fibre found in fruit and vegetables are known to support the health of the beneficial bacteria in our gut (probiotics) which in turn can help restore immune functioning.[8]
A specifically formulated diet as set out in Nutritious: Metabolic Fasting for Cancer can help prime the immune system so that it is better able to detect cells becoming cancerous, as well as providing foods and nutrients that have anticancer, antiviral and antimicrobial properties, which can be helpful to strengthen your immunity and keep you healthy.
The human body has an amazing ability to heal given the right tools.
References
[1] World Cancer Research Fund/American Institute for Cancer Research. Diet, Nutrition, Physical Activity and Cancer: a Global Perspective. Continuous Update Project Expert Report 2018. Available at dietandcancerreport.org [2] Wei, E. K., Wolin, K. Y., & Colditz, G. A. (2010). Time course of risk factors in cancer etiology and progression. Journal of clinical oncology: official journal of the American Society of Clinical Oncology, 28(26), 4052–4057. https://doi.org/10.1200/JCO.2009.26.9324 [3] Christ A, Lauterbach M, Latz E. Western Diet and the Immune System: An Inflammatory Connection. Immunity. 2019 Nov 19;51(5):794-811. doi: 10.1016/j.immuni.2019.09.020. PMID: 31747581. [4] Coussens, L. M., Zitvogel, L., & Palucka, A. K. (2013). Neutralizing tumor-promoting chronic inflammation: a magic bullet?. Science (New York, N.Y.), 339(6117), 286–291. https://doi.org/10.1126/science.1232227 [5] Soldati, L., Di Renzo, L., Jirillo, E., Ascierto, P. A., Marincola, F. M., & De Lorenzo, A. (2018). The influence of diet on anti-cancer immune responsiveness. Journal of translational medicine, 16(1), 75. https://doi.org/10.1186/s12967-018-1448-0 [6] Iida, N., Dzutsev, A., Stewart, C. A., Smith, L., Bouladoux, N., Weingarten, R. A., Molina, D. A., Salcedo, R., Back, T., Cramer, S., Dai, R. M., Kiu, H., Cardone, M., Naik, S., Patri, A. K., Wang, E., Marincola, F. M., Frank, K. M., Belkaid, Y., Trinchieri, G., … Goldszmid, R. S. (2013). Commensal bacteria control cancer response to therapy by modulating the tumor microenvironment. Science (New York, N.Y.), 342(6161), 967–970. https://doi.org/10.1126/science.1240527 [7] Mundi MS, Mohamed Elfadil O, Patel I, Patel J, Hurt RT. Ketogenic diet and cancer: Fad or fabulous? JPEN J Parenter Enteral Nutr. 2021 Nov;45(S2):26-32. doi: 10.1002/jpen.2226. PMID: 34897736. [8] Lundin A, Bok CM, Aronsson L, Björkholm B, Gustafsson JA, Pott S, Arulampalam V, Hibberd M, Rafter J, Pettersson S. Gut flora, Toll-like receptors and nuclear receptors: a tripartite communication that tunes innate immunity in large intestine. Cell Microbiol. 2008 May;10(5):1093-103. doi: 10.1111/j.1462-5822.2007.01108.x. Epub 2007 Dec 17. PMID: 18088401.