The effect of inulin on intestinal symptoms and quality of life in individuals with constipation-predominant irritable bowel syndrome

This study aims to evaluate the impact of inulin on bowel symptoms and the quality of life in individuals with constipation-predominant irritable bowel syndrome (IBS). The study was conducted with individuals diagnosed with predominant constipation-type IBS in the age range of 21-63 (n=34). The individuals were divided into two groups, namely the prebiotic group [(n=17) (twice daily 4.6 g (Inulin=total 9.2 g) inulin/oligofructose 50/50 mixture)] and the placebo group[(n=17), (Maltodextrin=9.2 g)]. The intervention period lasted for 8 weeks, during which anthropometric measurements, biochemical parameters, food frequency questionnaire, and 24-h dietary recall were taken at the beginning of the intervention, at the end of the 1st month, and at the end of the 2nd month. Additionally, various scales, including the Bristol Stool Scale, IBS-Symptom Severity Score (IBS-SSS) Scale, IBS-Visual Analog Scale, IBS-Quality of Life (IBS-QoL) Scale, and Beck Depression Inventory, were administered at the beginning of the intervention, at the end of the 1st month, and the end of the 2nd month. Statistical analysis of the data was performed using SPSS software. The average age of the prebiotic group in the study was 38.58±2.03 years, while the placebo group was 38.05±3.17 years. The majority of the study participants were females (76.4%). Distributions of age, gender, marital status, smoking, alcohol consumption, physical activity, reason for consulting a doctor, and comorbid diseases were similar among the research groups. Throughout the study, it was determined that the prebiotic group had a higher protein intake, while the placebo group had a higher fat intake. The protein percentage of the prebiotic group increased significantly over time at the end of the study (p<0.05). The majority of both groups were categorized as sedentary in the baseline, 1st-month, and 2nd-month measurements. There was a significant difference between the groups only in body mass index (BMI) baseline and 1st-month measurements (p<0,05). It was observed that the body fat percentage in the prebiotic group significantly decreased at the end of the study (p<0,05). In the prebiotic group, fasting blood glucose, creatinine, total cholesterol, and AST values decreased significantly over time at the end of the study (ptime<0,05). While the IBS-QoL score increased in the prebiotic group at the end of the study (ptime<0,05), the IBS-SSS score decreased (p<0,001). The total IBS-SSS score was found to be statistically significant in terms of group and time interaction effects [p<0.05]. Significant improvements were observed in abdominal pain, constipation, bloating/gas, and the impact of symptoms on daily life parameters in the prebiotic group at the end of the study (ptime<0.05). In individuals with constipation, improvement has been observed in terms of group and time interaction (ptime×group<0.05). There is a negative and moderate-level relationship between the BMI values and quality of life scores of the prebiotic group at 1st and 2nd months (p<0.05). In conclusion, in individuals with constipation, inulin supplementation may have a reliable and beneficial effect on quality of life and bowel functions in terms of stool frequency, consistency, and transit time. However, the prebiotic group did not exhibit a significant superiority over the placebo group in terms of defecation type, energy, macronutrient intake, and depression. Recommendations for individuals include regular consumption of main meals and snacks, adequate energy, macronutrient and fluid intake, reduction of caffeine, alcohol, and fat intake if associated with symptom formation, ensuring and increasing appropriate fiber intake, encouraging physical activity, and providing psychological support (cognitive-behavioral therapy) to reduce stress. It is crucial for individuals to have their nutrition assessed by a dietitian and to follow up on nutrition therapies from the moment of diagnosis.