What’s the Latest in Prebiotic Research?

December 2025

Inulin-induced improvements on bowel habit and gut microbiota in adults with functional constipation: findings of a randomized, double-blind, placebo-controlled study

Functional constipation is characterized by irregular bowel movements, hard stools, and a reduced abundance of butyrate-producing bacteria. This randomized, double-blind, placebo-controlled, cross-over trial assessed the effects of chicory inulin supplementation in adults with functional constipation. Thirty-nine adults (aged 18-75 years) with functional constipation according to Rome III criteria, were included and assigned to receive either 12 g of inulin or placebo (maltodextrin) daily for 4 weeks, with a 4-week wash-out between periods. The inulin was consumed at two doses of 6 g/day, except for the first 3 days, during which participants consumed only one 6 g dose per day. The primary outcome of this study was the change in stool frequency, and secondary outcomes included changes in stool consistency (Bristol Stool Form Scale (BSFS), quality of life related to constipation (Patient Assessment of Constipation – Quality of Life (PAC-QOL) scores), constipation-related symptoms (Patient Assessment of Constipation – Symptoms (PAC-SYM) scores), use of laxatives, physical activity (International Physical Activity Questionnaire (IPAQ)), and fecal microbiota composition. Inulin supplementation led to improvements in stool frequency, abdominal symptoms, PAC-QOL, and PAC-SYM. There were no significant changes observed in stool consistency or microbiota composition; however, relative abundance of the butyrate-producing Anaerostipes spp. and Coprococcus 1 spp. increased after intervention with inulin. During the intervention, gastrointestinal (GI)-related adverse events, including flatulence, bloating, and cramps were reported. Carry-over effects were also observed, with half of the participants who received inulin during the first period presented the greatest improvements across all outcomes during inulin intake. Overall, this study suggests that inulin supplementation provides beneficial effects in adults with functional constipation, including increased stool frequency, reduced abdominal symptoms, improvements in quality of life, and favourable changes in the gut microbiota.

Key takeaways:

  • Functional constipation is characterized by infrequent bowel movements, hard stools, and is often associated with a reduced abundance of butyrate-producing bacteria.
  • Inulin supplementation may improve stool frequency, alleviate abdominal symptoms, and increase butyrate producing bacteria.
  • Increased dietary fiber intake from inulin may cause GI-related adverse events, such as flatulence and bloating; further studies should also account for potential carry-over effects of inulin supplementation.

Access the study: https://link.springer.com/article/10.1186/s12876-025-04409-6

Reference: Puhlmann, M. L., Wegh, C. A. M., van der Zalm, S. C. C., Dam, V., Doolan, A., Meyer, D., Belzer, C., Vaughan, E. E., Benninga, M. A., & Smidt, H. (2025). Inulin-induced improvements on bowel habit and gut microbiota in adults with functional constipation: findings of a randomized, double-blind, placebo-controlled study. BMC gastroenterology, 25(1), 806. https://doi.org/10.1186/s12876-025-04409-6

Iron absorption and loss, and efficacy of iron supplementation with and without prebiotics in children with virally suppressed HIV: three prospective studies in South Africa

Children living with HIV often experience impaired iron absorption or increased GI iron loss due to low-grade systemic inflammation and viral replication within the gut mucosa, placing affected individuals at risk of iron deficiency. Three prospective studies were conducted within South Africa specifically examined iron metabolism in children living with HIV. The first study assessed short-term iron absorption from common iron interventions under controlled conditions, while the second examined longer-term iron absorption from the habitual diet and accounts for endogenous losses under real-world dietary and inflammatory conditions. The third study evaluated the efficacy and safety of oral iron supplementation, with and without galacto-oligosaccharide (GOS), in iron-deficient children with virally supressed HIV using a randomized, double-blind, placebo-controlled design. Eighty-six children aged 10-15 years were included and received daily supplementation for 12 weeks with either 50 mg of elemental iron (ferrous fumarate) plus 7.5 g of GOS, or 50 mg of iron plus placebo. Outcomes assessed were serum ferritin concentrations, iron status biomarkers, systemic and gut inflammation, gut integrity, HIV disease markers, fecal bacteria, adverse events, and self-reported GI and respiratory symptoms. The results suggested improvements in iron status markers in both groups, with a trend towards higher serum ferritin in the iron plus GOS group compared to the iron plus placebo group. Also, the incidence of fever, rhinorrhea, and flatulence was lower in the iron plus GOS group compared to placebo. Overall, these findings suggests that oral administration with iron plus GOS enhances serum ferritin and reduces fever and rhinorrhea, improving the efficacy and safety of iron supplementation among children living with HIV.

Key takeaways:

  • Low-grade systemic inflammation and viral activity in the gut mucosa contribute to reduced iron absorption and increased GI iron loss among children living with HIV.
  • The third study was a randomized controlled evaluating the safety and efficacy of oral iron combined with the prebiotic GOS in children with virally suppressed HIV.
  • Iron plus GOS showed a trend towards higher serum ferritin levels and reduced incidence of fever, rhinorrhea, and flatulence.

Access the study: https://www.nature.com/articles/s41467-025-64998-4

Reference: Baumgartner, J., Blaauw, R., Mikulic, N., Goosen, C., Barnabas, S. L., Cotton, M. F., & Zimmermann, M. B. (2025). Iron absorption and loss, and efficacy of iron supplementation with and without prebiotics in children with virally suppressed HIV: three prospective studies in South Africa. Nature communications, 16(1), 9929. https://doi.org/10.1038/s41467-025-64998-4

A randomized trial of inulin for bowel symptoms, depression and quality of life in constipation predominant IBS

Irritable bowel syndrome (IBS) is a GI disorder that is characterized by abdominal pain, bloating, gas, and irregular bowel habits. IBS can be classified into constipation-predominant, diarrhoea-predominant, mixed, or unspecified. This randomized, single-blind, parallel, placebo-controlled, clinical trial assessed the effects of oral supplementation with inulin among adults with constipation-predominant IBS. Thirty-four adults (aged 19-65 years) with constipation-predominant IBS according to Rome IV criteria were included in this study. Participants were divided into two groups to receive either 9.2 g of inulin/oligofructose (50/50 blend) or placebo (maltodextrin) daily for 8 weeks. Measurements included the Bristol Stool Scale, IBS, Visual Analogue Scale (IBS-VAS), IBS-Symptom Severity Score Scale (IBS-SSS), IBS-Quality of Life Scale (IBS-QoL), and Beck Depression Scale. Following prebiotic supplementation, participants in the prebiotic group showed increased IBS-QoL scores, decreased IBS-SSS scores (including abdominal pain, pain frequency, bloating, and dissatisfaction with bowel movements), and improved stool form. Additionally, improvements in IBS-VAS scores for constipation status and psychological state were observed within the prebiotic group. Also, Beck Depression Scale scores were lower after months 1 and 2 compared to placebo. Overall, this study suggests that supplementation with an inulin/oligofructose blend may benefit adults with constipation-predominant IBS by reducing symptom severity and improving quality of life.

Key takeaways:

  • IBS is a GI disorder characterized by abdominal pain, bloating, gas, and irregular bowel habits, and can be classified into subtypes such as constipation-predominant IBS.
  • This study evaluated the effects of an inulin/oligofructose prebiotic supplement in adults with constipation-predominant IBS for 8 weeks.
  • Participants receiving the prebiotic experienced improvements in constipation symptoms and quality of life.

Access the study: https://pmc.ncbi.nlm.nih.gov/articles/PMC12488941/

Reference: Akçalı, Ç., Uçar, A., & Atay, K. (2025). A randomized trial of inulin for bowel symptoms, depression and quality of life in constipation predominant IBS. Scientific reports, 15(1), 34252. https://doi.org/10.1038/s41598-025-16321-w

Time-restricted eating and prebiotic supplementation demonstrate feasibility and acceptability in young adult pediatric cancer survivors: a randomized controlled pilot trial

Pediatric cancer survivors (PCSs) tend to exhibit increased adiposity, perturbation in the gut microbiome, chronic systemic inflammation, a heightened risk of long-term chronic disease. Time-restricted eating (TRE) is an effective weight-management method that involves limiting food intake to specific time windows as opposed to counting calories. This 12-week randomized controlled pilot study assessed the feasibility, acceptability, and safety of TRE with and without a prebiotic supplement in PCSs. Thirteen participants (aged 18-39 years) with overweight or obesity were assigned to one of two groups; 1) TRE group: 8-hour TRE, with ad libitum food intake from 12:00 PM to 8:00 PM and water-only fasting from 8:00 PM to 12:00 PM or 2) PreTRE group: 8-hour TRE plus prebiotic supplement (one 3.65 g sachet of Bimuno® GOS, providing 2.75 g active GOS). Measurements included body weight, body composition, blood pressure, and cardiometabolic disease risk markers. The results indicated improvements in cardiometabolic risk markers, including reductions in fat mass and visceral fat mass in both treatment groups. Also, participants in the PreTRE group showed significant decreases in fasting insulin after intervention. Both groups also showed decreases in total cholesterol, low-density lipoprotein (LDL) cholesterol, high-sensitivity C-reactive protein (hs-CRP), and homeostatic model of insulin resistance (HOMA-IR) after intervention, although these changes were not statistically significant. Of note, changes in GI symptoms did not differ between the TRE and PreTRE groups. The intervention was well tolerated, with no major safety concerns and only a few minor adverse events reported. The study was limited by its small sample size and therefore a larger study is warranted in populations of PCSs.

Key takeaways

  • TRE is an effective weight-management strategy that limits food intake to specific hours rather than focusing on calorie counting.
  • TRE, alone or in combination with a prebiotic, appears well tolerated and feasible, with no major adverse events reported among PCSs.
  • Adding a prebiotic to TRE did not result in additional weight loss in overweight or obese PCSs.

Access the study: https://www.mdpi.com/2072-6643/17/20/3306

Reference: Cares, K., Lima Oliveira, M., Bryner, A., Man, B., Chen, Z., Bernabé, B. P., Schmidt, M. L., Fitzgibbon, M., & Gabel, K. (2025). Time-Restricted Eating and Prebiotic Supplementation Demonstrate Feasibility and Acceptability in Young Adult Pediatric Cancer Survivors: A Randomized Controlled Pilot Trial. Nutrients, 17(20), 3306. https://doi.org/10.3390/nu17203306