The Link Between Fiber, Cancer & the Gut Microbiome

15 November 2022by Barış Özdinç

Recent breakthroughs in cancer research are revealing a profound connection between the gut microbiome, dietary habits, and the success of cancer immunotherapy.

While we have previously come to understand the wider links between the microbiome and cancer, this research dives into the specific link between dietary fiber, cancer and the gut microbiome.

As reported by the Washington Post, the human gut microbiome, teeming with bacteria, fungi, phages, and other microbes, can play a crucial role in shaping our immunity, health, and overall balance.

Read on to discover exactly how the gut microbiome, fiber and cancer are all linked, and the potential outcomes this could have for human health.

The Gut Microbiome and Cancer Immunotherapy

A recent article in the Washington Post highlights a link between the gut microbiome composition and cancer immunotherapy treatment outcomes. The human gut microbiome consists of a vast array of bacteria, fungi, phages and other microbes. The interactions between the microbes and their interconnection with the host affects host immunity, health and homeostasis. 

In this context, it may be unsurprising that changes to the gut microbiome may also influence cancer outcomes. According to several different studies, the gut microbial composition can modulate the success of a ground-breaking cancer treatment, immunotherapy. Cancer patients with certain gut bacteria had a better response to immunotherapy than patients who lacked them. 

Scientists from the University of Chicago demonstrated that feeding mice a strain of Bifidobacterium increased immune response against melanoma tumors and slowed their growth as compared to mice who lacked the bacteria. 

What’s more, combining the bacteria with immunotherapy nearly abolished the tumors. 

What’s the Link Between Fiber and Cancer?

In short: the gut microbiome. 

The Western diet, high in processed foods and low in fiber has been linked to increased incidence of a number of high-impact diseases, including inflammatory bowel disease and colon or colorectal cancer.

But it is not just our dietary habits that are responsible for this connection. It turns out that dietary fiber plays a significant role in promoting the growth of certain bacteria, such as Bifidobacterium, which have shown potential in fighting cancer cells. 

Fiber serves as food for these beneficial bacteria, allowing them to thrive and produce beneficial metabolites that can help fortify the immune system against cancer. This highlights the importance of a rich dietary fiber intake for maintaining a healthy gut microbiome, and potentially reducing the risk of developing certain types of cancer.

Dietary Fiber and Probiotics: A Potential Game-Changer

Human studies showed a similar immunotherapy outcome improvement in cancer patients whose guts had more microbial diversity, as well as a greater abundance of several microbes, including Akkermansia muciniphila and Bifidobacterium longum

Furthermore, new research highlights that consuming more dietary fibers and probiotics including Bifidobacterium and Lactobacillus may improve cancer immunotherapy treatment. Giving patients a more fiber-rich diet of fruits, produce, beans, nuts and whole grains improves the microbiome and their odds of response to cancer immunotherapy treatment.

Clinical Trials at MD Anderson Cancer Center

These impressive results led to a formal clinical trial at the University of Texas MD Anderson Cancer Center in Houston, the largest cancer center in the United States. 

Hector Facton, a pediatrician undergoing immunotherapy treatments for Stage 4 melanoma in the clinical test, stated that he has been eating triple the amount of fruits and veggies than he used to eat, and adds he also eats lots of quinoa or anything else with lots of fibers in it. 

High Fiber Diet: Caution and Hope

Although scientists caution against the strategy of using a fiber-rich diet to boost immunotherapy, as it remains clinically unproven, the clinical research is shedding new light on how the gut microbiome affects our ability to fight cancer. 

Cancer patients often want to know what they can personally do to improve their treatment outcomes. Although increasing fiber intake can be recommended by physicians, this clinical study will show definitively whether this is clinically significant in immunotherapy response, which may give patients a greater sense of hope and control over their disease. 

Dietary fiber intake, gut microbiota composition and cancer summary

In light of the aforementioned research, the integral role of dietary fiber consumption in shaping the human gut microbiota emerges clearly. It is noteworthy that a higher dietary fiber intake, particularly in the form of fruits, vegetables, and whole grains, promotes the growth of beneficial microbes in our gut. This, in turn, reflects in the improved health outcomes, including enhanced response to cancer immunotherapy.

One of the mechanisms through which dietary fibers exert their beneficial effects is by serving as substrates for carbohydrate active enzymes. These enzymes, produced by the gut bacteria, break down complex carbohydrates, including insoluble fiber, into simpler compounds. 

The resultant compounds, primarily short chain fatty acids, serve a key role in maintaining gut health and supporting the immune system. They create an unfriendly environment for pathogenic bacteria and provide energy for the gut lining cells, contributing to maintaining the integrity of the gut barrier.

Lastly, a pivotal way in which the microbiota influences the host is through signaling via G protein-coupled receptors (GPCRs), specifically referred to as metabolite-sensing GPCRs. 

Within the gut, GPCRs are expressed by both immune and nonimmune cells, and their activation typically delivers anti-inflammatory signals by regulating both immune system activities and the integrity of the epithelium. Members of the GPCR family act as a bridge connecting the microbiota, the immune system, and the intestinal epithelium, all of which play a crucial role in maintaining gut homeostasis.

The Future Landscape: Integrating Microbiome Insights into Treatment Plans

The future landscape of cancer treatment is expected to evolve, integrating microbiome insights into its core strategies. As our understanding of the gut microbiome deepens, its role in enhancing immunotherapy will likely be recognized by mainstream medicine.

It’s envisaged that treatment plans will not only focus on administering medicine, but also on tailoring diets to modify the gut microbiome. This holistic approach may seek to increase the intake of dietary fibers or the use of probiotics to enhance the body’s immune response.

Moreover, there are potential prospects for the development of ‘microbial interventions’ – a form of treatment that might include fecal transplants, probiotic bacteria, or other microbial products. Additionally, the possibility of personalized medicine based on one’s microbiome composition could become a reality.

However, it’s important to underscore that these applications require rigorous clinical trials to verify their efficacy and to evaluate potential risks. How we integrate these promising microbiome insights into cancer treatment plans will be a crucial determining factor in the fight against cancer in the forthcoming years.

Unlock the Power of the Microbiome with CosmosID

In conclusion, the complex interplay between dietary fiber intake, gut microbes, and cancer prognosis underscores the potential of dietary fiber interventions as an adjunct to traditional cancer treatments. 

While further research is warranted to fully elucidate the mechanisms underlying these interactions, the current evidence offers both hope and a promising avenue for enhancing treatment outcomes and human health in cancer patients.

At CosmosID, our state-of-the-art microbiome sequencing and metagenomics platform, the CosmosID-HUB, has supported numerous research studies exploring the role of the microbiome in various health conditions, including cancer.

With our advanced computational tools and extensive database of microbial reference sequences, we can help unlock the power of the microbiome for a better understanding of disease progression and treatment efficacy.

To learn more about how CosmosID can support your research, contact us today!

Barış Özdinç

Barış Özdinç analyzes microbiome research with his educational background in genetics and evolution. As a research analyst for CosmosID, he combines metagenomics and data analyses to identify microbial biomarkers in disease cohorts and evaluate microbiome research tools. His work involves curating microbiome data and creating interesting microbiome content for newsletters and blog posts. Barış Özdinç received his bachelor’s degree in genetics and master’s degree in biodiversity, evolution, and conservation from University College London (UCL). Currently, he lives in Istanbul, Turkey, where he lives with his cat, Delight, and mentors female students in their STEM career pursuits.