Introduction: Irritable bowel syndrome (IBS) is a functional bowel disease accompanied by symptoms such as chronic abdominal pain, bloating, gas and defecation disorders triggered by some dietary compounds and foods. A gluten-free diet and recently approved diet called a low-FODMAP diet, which affects dietary soluble and insoluble fibre intake are applied to relieve these symptoms⁽¹⁾. These diets affect gut microbiomes that include beneficial microorganisms for human health⁽²⁾. This study was aimed to evaluate different medical nutrition therapies on dietary fibre intake, which may cause dysbiosis in the gut.

Methods: In this study, forty-five patients aged 19-64 diagnosed with constipation-predominant IBS (IBS-C) according to Rome-IV criteria were randomized into three groups of 15 patients each. Each group adopted either a gluten-free diet, low-FODMAP (fermentable oligo-, di-, monosaccharides and polyols) diet or traditional constipation diet for six days. Participants were asked to keep a food diary using 24-hour food record for each day. At the end of the study, the food diaries were evaluated in total dietary soluble and insoluble fibre intake using Nutrition Information System software (BeBiS).

Results: Participants mean age was 37.6±11.2 year, and body mass index 25.6±3.2 kg/m2. Mean total dietary soluble fibre intake of traditional constipation diet group was 12.8±4.4 g, gluten-free diet group was 11.6±3.1 g and low-FODMAP diet group was 9.0±4.0 g. The difference in total dietary soluble fibre intake between groups was statistically significant (p = 0.033). Mean total dietary insoluble intake of traditional constipation diet group was 22.9±6.6 g, gluten-free diet group was 23.2±5.3 g, and low-FODMAP diet group was 16.9±6.9 g. Total dietary insoluble intake was the lowest for low-FODMAP diet groups and found statistically significant (p=0.024).

Conclusion: Gut microbiome needs to be supported by diet to increase its number and maintain host health. Dietary fibre, especially soluble fibre, is one of the primary energy sources of the microbiome. Even though low-FODMAP and gluten-free diets are effective to relieve the symptoms of IBS-C, they are restricted from dietary fibre. Compared to these two diets, a traditional constipation diet includes more fibre however it is not enough for a healthy diet. To support patients' dietary intervention with enough soluble fibre may be helpful for the gut microbiome.

The dietary fiber intake of patients with constipation-predominant irritable bowel syndrome who applied different medical nutrition therapies

The gastrointestinal tract is amongst the most densely populated ecosystems on earth, home to an abundant and diverse collection of microbial species, not just bacteria but also Archaea, viruses, fungi etc. Significant interest in this area has been sparked in recent years by an appreciation of the importance of the gut microbiota in the health of the host, and this has led to the microbiome of humans and animals being investigated in depth. Studies have drawn links between host nutrition, the gut microbiota and metabolic and immune functions, which in consequence affect physiology.



The first investigations of the structure of the microbiota were culture-based, however the introduction of sequencing technologies such as Sanger sequencing and subsequent development of 454 sequencing and metagenomics approaches have become the mainstay of microbiota studies. The creation of reference databases and analysis software has provided invaluable tools for assigning taxonomy to generated data. Great progress in characterising the structure of the microbiome recently has paved the way for ongoing and future studies on the functional interactions between the microbiota and the host. Studies on the function of the microbiota are critical in understanding the role of the microbiota in human homeostasis and disease pathogenesis.



The conference will be presenting the latest advancements in gut microbiome and health research. It will bring together experts who are driving technological advancements and striving to understand how nutrition impacts gut microbiome and the interactions between gut microbiome and health.



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