Introduction

Inflammatory Bowel Disease (IBD) is a chronic inflammatory disease of the gut and bowels. The 2 conditions that are commonly associated with IBD are Crohn’s disease (CD) and ulcerative colitis (UC). The differences between CD and UC lie in the following [1]:

• Location: inflammation can affect any part of the gastrointestinal (GI) tract for CD; for UC, it is limited to the colon and the rectum
• Type: damaged tissues appear in patches in CD, whereas the damaged areas are often continuous in UC
• Extend: the extend of inflammation can affect multiple layers of the GI tract in CD, while inflammation is only often present in the innermost layer of the colon in UC.

An estimated 3 million adults from the United States (U.S.) suffer from IBD [2], with many more children under the age of 18 years old being diagnosed as well [3]. Common symptoms of IBD may resemble irritable bowel syndrome (IBS), but they are not the same condition. Some symptoms include abdominal pain, weight loss, and rectal bleeding.

The health of your gut and the gut microbiota (also called gut microbiome) has been shown to affect inflammation, which is the key feature of IBD [4]. Fiber intake may also have certain roles in the cause of IBD, which includes (but not limited to) its effects as a prebiotic for the gut microbiota.

World IBD Day falls on 19 May every year [5]. In conjunction with this day, find out how the health of your gut (including your gut microbiota) is related and associated with this autoimmune and inflammatory disease of the bowels!

Gut Health: What is the Gut Microbiota?

The human digestive system and health is greatly affected by the microorganisms harbored within the gut, which includes bacteria, virus, and fungi species. This is termed as the gut microbiota, with the number of bacterial cells estimated to be more than 10 times the number of human cells [6]. Its composition is unique to everyone, as several factors such as environmental and lifestyle contribute to the uniqueness of the gut microbiota composition [7].

Indications of an unhealthy digestive system can range from local (i.e., gut-related) such as digestive issues, to more systemic-related problems like skin health, mood swings, and even depression [8], and many of these effects may be contributed by the gut microbiota [9]. A change in the bacterial species and environment could happen because of drugs (e.g., antibiotics), toxins, and pathogens. This is called ‘dysbiosis’ [10].

How The Gut Microbiota affects IBD

There have been several published reports that studied the effects of the gut microbiota on IBD, mainly reflected by the gut microbiota’s effect on reducing inflammation.

Dysbiosis has been observed in patients with IBD as compared to healthy individuals [11]. As a healthy gut microbiota has been associated with anti-inflammatory effects on the gut, dysbiosis could have pro-inflammatory effects on the gut, leading to symptoms of IBD. An increase in the number of ‘bad’ bacteria in the gut also affects the gut in other ways, such as changing the permeability of the intestine walls [11]. This effect has also been shown in animal studies, where rats with gut microbiota changes induced by using antibiotics were associated with recurrent gut inflammation [12].

The gut microbiota also produces short-chain fatty acids (SCFAs) through the fermentation of prebiotics such as dietary fiber [9]. The concentrations of these SCFAs were also found to be lower in IBD patients, which may also play a part in inducing inflammation, leading to IBD and its respective symptoms [11].

How Can Dietary Changes Help with IBD?

Dietary changes that target gut microbiota may help to alleviate IBD symptoms [13]. The Anti-inflammatory Diet for IBD (IBD-AID) has been researched and studied as an adjunct therapy for IBD treatment [14]. The IBD-AID includes the use of more prebiotic and probiotic foods to restore the healthy levels of gut microbiota. According to the study, a 61.3% of patients on IBD-AID for 8 weeks reported a significant decrease in IBD symptoms [14]. IBD-AID also emphasize on the importance of using soluble fiber, which also promotes benefits such as SCFAs production by the gut microbiota, as mentioned above as well [15].

Prebiotics are substrates that are used and broken down by the gut microbiota to form metabolites such as SCFAs. Different forms of prebiotics include [16]:

• Resistant starches such as Fibrosol
• Frutans
• Galacto-oligosaccharides
• Pectin

Conclusion

Inflammatory Bowel Disease (IBD) is a chronic inflammatory disease that can affect any part of the gastrointestinal system, depending on the type of IBD. The gut microbiota and alterations of the composition of it has been associated with IBD, as dysbiosis has been shown to be observed in patients with IBD as compared to healthy individuals. Dietary changes such as increasing the usage of prebiotic and soluble fiber may be useful in alleviating the symptoms of IBD.

This article is written in conjunction with World IBD Day, which falls on 19 May every year.

References

1. Centers for Disease Control and Prevention (CDC). Inflammatory bowel disease (IBD): What is IBD? 2018 March. Available on: https://www.cdc.gov/ibd/what-is-IBD.htm
2. Centers for Disease Control and Prevention (CDC). Inflammatory bowel disease (IBD): Data and Statistics. 2021 November. Available on: https://www.cdc.gov/ibd/data-statistics.htm
3. Pituch-Zdanowska A, Banaszkiewicz A, Albrecht P. The role of dietary fibre in inflammatory bowel disease. Prz Gastroenterol. 2015;10(3):135-141. Available on: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4607699/
4. National Institutes of Health (NIH). Changing gut bacteria in Crohn’s disease. 2017 December. Available on: https://www.nih.gov/news-events/nih-research-matters/changing-gut-bacteria-crohns-disease
5. World IBD Day. 2022. Available on: https://worldibdday.org/
6. Thursby E, Juge N. Introduction to the human gut microbiota. Biochem J. 2017;474(11):1823-1836. Available on: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5433529/
7. Rutsch A, Kantsjö JB., Ronchi F. The Gut-Brain Axis: How Microbiota and Host Inflammasome Influence Brain Physiology and Pathology. Immunol. 2020;11. Available on: https://www.frontiersin.org/articles/10.3389/fimmu.2020.604179/full
8. Digestive Health: An Introduction. 2022 April. Available on: https://fibrosol.com/digestive-health-an-introduction/
9. What is the Gut Microbiota? 2021. Available on: https://fibrosol.com/what-is-the-gut-microbiota/
10. Bourassa MW, Alim I, Bultman SJ, Ratan RR. Butyrate, neuroepigenetics and the gut microbiome: Can a high fiber diet improve brain health?. Neurosci Lett. 2016;625:56-63. Available on: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4903954/
11. Nishida A, Inoue R, Inatomi O, et al. Gut microbiota in the pathogenesis of inflammatory bowel disease. Clin J Gastroenterol. 2018 Feb;11(1):1-10. Available on: https://link.springer.com/article/10.1007/s12328-017-0813-5
12. Schaubeck M, Clavel T, Calasan J, et al. Dysbiotic gut microbiota causes transmissible Crohn's disease-like ileitis independent of failure in antimicrobial defence. 2016;65:225-237. Available on: https://gut.bmj.com/content/65/2/225
13. To Help IBD Symptoms, Target Your Microbiome with These Foods. 2020 January. Available on: https://www.healthline.com/health-news/microbiome-diet-may-help-ibd
14. Olendzki BC, Silverstein TD, Persuitte GM, et al. An anti-inflammatory diet as treatment for inflammatory bowel disease: a case series report. Nutr J. 2014 Jan 16;13:5. Available on: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3896778/
15. UMass Chan Medical School, Center for Applied Nutrition. Anti-Inflammatory Diet for IBD (IBD -AID). Available on: https://www.umassmed.edu/nutrition/ibd/ibdaid/
16. Overview of Prebiotics. 2021. Available on: https://fibrosol.com/overview-of-prebiotics/