Hello Habiba Sundus

There is an established connection between the bacterial component of the human gut microbiome and certain types of cancer like colorectal cancer, with certain microbial products and activities contributing to risk of tumor development while other traits are protective against colorectal cancer. Exercise could mediate changes that could promote the antitumorigenic characteristics of the gut microbiota. This inverse relationship between exercise and colorectal cancer involves the gut microbiota.

The gut microbiome has been shown to influence colorectal cancer risk via multiple routes including altered metabolite production, DNA damage, derangements in cellular processes and immune responses that contribute to microenvironmental conditions that can initiate and propagate colorectal cancer.

Exercise may alter the gene expression of intraepithelial lymphocytes residing within the gastrointestinal tract, promoting the release of anti-inflammatory cytokines, and enhancing microbial homeostasis. Other potential mechanisms include altered integrity of the gut mucus layer, increased core temperature, reduced intestinal blood flow during exercise and subsequent reperfusion during rest, improved gut motility and activity of the enteric nervous system, which may impact intestinal pH, mucosal secretion, and availability of nutrients for the microbiome following exercise.

The intensity of exercise will also matter. Longer duration or higher intensity, exercise allows for more oxygen to reach the brain and bloodstream. Researchers mention that this is an environment for good bacteria to flourish.

The effects of low intensity exercise on the microbiome can influence the gastrointestinal tract by reducing the transient stool time (the time it takes for food to move through the digestive tract). This is important for the microbiome because a healthy digestive tract means that gut microbiota can effectively perform their multiple functions, which includes optimizing the body’s cells that turn non-digestible components of food into energy.

Though exercise may have a beneficial impact on the gut, the microbiome won’t be fully optimized unless one has a good healthy diet along with exercise. Healthy diet and exercise complement each other to optimize overall health, including gut biome. If one provides the body with nutrient-dense and anti-inflammatory foods as well as work out consistently, one will provide the body with what it needs to optimize all functions and boost the immune system.

A microbiome must be resistant, resilient, and stable to perturbation and thereby, the functional ‘housekeeping’ aspects of the gut microbiota are maintained. It would be difficult to define a so called ‘healthy’ microbiome because of the significant inter- and intra-variability that exists for the gut microbiota, as well as the functional diversity and redundancy inherent to different microbes. Furthermore, there are other factors which you mentioned such as age, genetics, diet, lifestyle choices and/or medications which can all coalesce and manifest to change the functional attributes of the gut microbiota.

I have attached a few articles for your reference which may help!

https://physoc.onlinelibrary.wiley.com/doi/10.1113/JP283702

https://www.fisiologiadelejercicio.com/wp-content/uploads/2023/12/Exercise-and-the-gut-microbiome-implications-for-supportive-care.pdf

https://acsjournals.onlinelibrary.wiley.com/doi/full/10.1002/cncr.34669

Article Exercise Modifies the Gut Microbiota with Positive Health Effects

Article The Microbiota: an Exercise Immunology Perspective

https://e-century.us/files/ajcr/12/10/ajcr0145332.pdf

Best.

As you have stated gut microbiome and cancer relations are maybe the most complex issue of all medicine as within the scope of gastrointestinal oncology. The secrets of this utmost complex issue with so many unsolved neoplastic mechanisms are hidden as if rooted in darkest unknown ocean deeps. I recommend you to read the links below...

Article Tumor microbiome metabolism: A game changer in cancer develo...

https://www.frontiersin.org/files/Articles/933407/fonc-12-933407-HTML/image_m/fonc-12-933407-t001.jpg

Exercise‐induced changes to the human gut microbiota and implications for colorectal cancer: a narrative review