I have posted many blogs on how your food influences prostate cancer (PCa) risk. Most of the research based content in my blogs is based on diet and inflammation. Since chronic inflammation is a known set up for many types of cancer, including PCa, the chain of events seems pretty obvious:

Western dietary style → chronic inflammation → PCa (or other cancers)

I recently came across a scientific paper that suggests the pathway is more complex. The chain includes an unexpected element. It’s your gut bacteria (also called microbiota). According to Matsushita, et al., “Diet composition and lifestyle have a direct and profound effect on the gut bacteria.” That may strike you as obvious, but I hope it makes you wonder what that has to do with PCa.

You may not realize it, but you’re walking around with a hundred trillion organisms, mostly bacteria, in your intestines. The interrelationship between you and these organisms is a normal part of life, and keeping them in peak condition and balance is important. When they go out of whack, it leads to a microbiota dysfunction called dysbiosis. Many factors can send your gut bacteria into dysbiosis: foreign pathologic bacteria, antibiotics, smoking, hormones, aging, and—you guessed it—diet.

The number of research studies connecting dysbiosis with the onset of colorectal and other cancers has flourished in the two decades since the new millennium. By 2013, there was no doubt that disturbing the gut microbiota was a causal factor in colorectal cancers. Continued research demonstrated an association of dysbiosis with both breast and liver cancers. In fact, “… the gut microbiota influences oncogenesis [the onset of cancer] and tumor progression both locally and systemically.”^[i] This means that other organs not connected with the digestive and excretion systems may be at higher risk for cancer, including the prostate.

Matsushita et al. recently published a paper that addresses three different lifestyle diets (Western, Prudent, and Traditional), dysbiosis and PCa.^[ii] The authors cite a 2017 study showing that “… gut microbiota, which is altered by various external factors, including dietary composition, is involved in all stages of cancer, including initiation, progression, treatment outcomes and adverse reactions.”^[iii] They point to a 2018 study by Liss, et al.^[iv] in which 133 U.S. patients who had prostate biopsies were found to have different concentrations of certain gut bacteria based on whether or not their biopsies were positive for PCa. Those who were indeed diagnosed with PCa had significantly more Bacteroides and Streptococcus spp., both of which are linked with intestinal inflammation.

The Matsushita study points out regional dietary differences and patterns of prostate cancer. They note that when mice are fed the equivalent of the Western diet (higher intake of red meat, processed meat, potatoes, and high-fat dairy products), their microbiota becomes less diverse. Also, some studies have
found an association between the Western diet and increased PCa risk, while the Prudent pattern (greater consumption of vegetables, fruits, legumes, and fish) was linked with less PCa incidence.

The typical Japanese diet follows the Traditional pattern for that country, consisting of high amounts of pickles, seafood, chicken, and Japanese sake. PCa risk has typically been lower in Japanese men than U.S. men—until they switch to a Western diet. One can only imagine the impact such a change has on the gut bacteria of Japanese men.

Matsushita and his co-authors may be onto something important, but their conclusion states more research needs to be done:

… the mechanisms by which gut microbiota control PCa have not been elucidated. Although the prostate is not an organ directly affected by gut microbiota, the prostate could be affected indirectly by cytokines and immune cells modified by microbiota in the gut or bacterial metabolites and components absorbed from the intestine that enter systemic circulation (i.e., a “microbiota-gut-prostate axis”).^[v]

The human body is a tightly woven, interdependent system that plays host to other organisms. In the case of gut bacteria, it’s a symbiotic relationship. They need us and we need them. When we provide them with what they need to survive, including healthy nutrients, in turn they perform functions or produce compounds that enhance our immune system and indirectly affect our energy level and even our brain health. Let’s not complicate that relationship by consuming unhealthy foods that can foster dysbiosis, setting up a chain reaction that threatens the innocent prostate gland.

NOTE: This content is solely for purposes of information and does not substitute for diagnostic or medical advice. Talk to your doctor if you are experiencing pelvic pain, or have any other health concerns or questions of a personal medical nature.

[i] Zitvogel L, Galluzzi L, Viaud S, Vétizou M et al. Cancer and the gut microbiota: an unexpected link. Sci Transl Med. 2015 Jan 21;7(271):271ps1.
[ii] Matsushita M, Fujita K, Nonomura N. Influence of Diet and Nutrition on Prostate Cancer. Int J Mol Sci. 2020 Feb 20;21(4):1447.
[iii] Dzutsev A., Badger J.H., Perez-Chanona E., Roy S., Salcedo R., Smith C.K., Trinchieri G. Microbes and Cancer. Annu. Rev. Immunol. 2017;35:199–228.
[iv] Liss M.A., White J.R., Goros M., Gelfond J., Leach R., Johnson-Pais T., Lai Z., Rourke E., Basler J., Ankerst D., et al. Metabolic Biosynthesis Pathways Identified from Fecal Microbiome Associated with Prostate Cancer. Eur. Urol. 2018;74:575–582.