A prebiotic intervention improves mood in everyday life in healthy women but not in men: Exploratory results from a larger double-blind placebo controlled cross-over study
Prebiotics may support mental health via the gut-brain axis, but the mechanisms underlying their effects on the gut microbiota need further research. This study explored results from a 32-week randomized, double-blinded, placebo-controlled crossover study where the participants were allocated to each intervention for 12 weeks separated by an 8-week wash-out period in-between. The purpose of this study was to assess the effect of a prebiotic supplement on the mood of adult participants in everyday life. Sixty-five healthy men and women (ages 45-70 years) were included in the study. Participants were instructed to consume 13 g of either a fiber blend (10 g acacia gum powder and 3 g milled carrot powder) or placebo (maltodextrin) for 12 weeks each. The designated powder was to be consumed daily with breakfast, mixed with 200-400 ml of milk, yoghurt, or smoothie. At baseline and weeks 4, 8, and 12 of each arm, data were collected via the short form 12v2 (SF-12) questionnaire, the gastrointestinal symptoms rating scale (GSRS), Bristol Stool Form Scale (BSFS), ecological momentary assessment (EMA), and cortisol awakening response (CAR). Visual analogue scales (VAS) were completed to assess positive and negative affect. Fecal samples were also collected for microbiome and short-chain fatty acid (SCFA) analysis, along with blood samples for inflammatory markers. Results demonstrated that daily supplementation with prebiotic fiber led to significant increases in positive affect and reduced negative affect in females only, compared to placebo. Furthermore, in this group, the reduction in negative affect reported was associated with increased microbial diversity at week 12. However, prebiotic fiber supplementation did not result in significant changes in fecal SCFA levels, cortisol, or inflammatory markers. Future studies should consider larger sample sizes to investigate intervention-induced mood changes in females and other sub-populations.
Key takeaways:
- Prebiotics may be beneficial for mental health via the gut-brain axis, although their exact mechanisms are unclear.
- This study showed that prebiotic supplementation with acacia gum and carrot powder may led to improved mood in female adult participants.
- Future research should focus on the underlying mechanisms behind the lack of observed effects in males compared to females.
Access the study: https://pmc.ncbi.nlm.nih.gov/articles/PMC11665422/
Reference: Hogenelst, K., Krone, T., Eveleens Maarse, B., Warnke, I., Snabel, J., van den Broek, T. J., Schuren, F., Moerland, M., & Hoevenaars, F. P. M. (2024). A prebiotic intervention improves mood in everyday life in healthy women but not in men: Exploratory results from a larger double-blind placebo controlled cross-over study. Brain, behavior, & immunity – health, 43, 100918. https://doi.org/10.1016/j.bbih.2024.100918
Effects of infant formula supplemented with prebiotics on the gut microbiome, gut environment, growth parameters, and safety and tolerance: a systematic review and meta-analysis
Human breast milk, rich in fermentable oligosaccharides known as human milk oligosaccharides (HMOs), is considered the ideal source of infant nutrition. When unavailable, prebiotic-supplemented cow’s milk formulas offer a close alternative. A systematic review and meta-analysis was conducted to assess the effects of cow’s milk-based infant formula supplemented with prebiotics, compared to a standard formula and human milk, on the gut microbiome, gut environment, growth parameters, and safety and tolerance in infants. A total of 30 articles reporting on randomized controlled trials sourced from PubMed, Embase, Chochrane Central Register of Controlled Trials, ProQuest Dissertations, and Theses were included. Articles were included if they involved healthy infants aged 6 months or younger who received cow’s milk-based formula supplemented with prebiotics for one month or more, compared to unsupplemented cow’s milk-based formula or human milk, and reported outcomes related to gut health, including the microbiome, gut environment, and/or growth measurements. Three studies reported an increased Bifidobacterium abundance from baseline at one, two, and three months in infants receiving the prebiotic formula containing 3 g/L, 4 g/L or 5 g/L fructo-oligosaccharides (FOS) compared with standard formula. Four other studies reported that infants receiving a prebiotic formula containing 2–5 g/L of FOS showed no significant increase in Bifidobacterium abundance compared to the standard formula at any time point and up to 15 weeks of supplementation. Overall, the findings revealed heterogeneity in the outcomes associated with different types and concentrations of prebiotics, including GOS, FOS, GOS + FOS, oligofructose + inulin, and polydextrose + GOS, added to infant formula compared to regular formula and/or human milk. While some studies showed significant effects on Bifidobacterium, others found no significant effects, which was similarly seen with the effects on Lactobacillus counts, depending on the type and concentration of prebiotics used. Although prebiotic-supplemented infant formula shows promising effects on Bifidobacterium compared to standard formula, the overall results are inconsistent. As such, future research should consider standardizing research designs as well as exploring dose-response relationships, ideal duration of supplementation, and other potential nutritional bioactive additives in human milk.
Key takeaways:
- Prebiotic-supplemented infant formula (especially those with FOS or GOS) may increase Bifidobacterium abundance compared to standard formula, though results vary depending on prebiotic type, dose, and duration.
- No significant effects were observed on Lactobacillus levels or with certain prebiotic combinations (e.g., oligofructose + inulin, polydextrose + GOS), highlighting variability in response depending on prebiotic type and blend.
Access the study: https://doi.org/10.1093/nutrit/nuae184
Reference: Kebbe, M., Leung, K., Perrett, B., Reimer, R. A., Adamo, K., & Redman, L. M. (2025). Effects of Infant Formula Supplemented With Prebiotics on the Gut Microbiome, Gut Environment, Growth Parameters, and Safety and Tolerance: A Systematic Review and Meta-Analysis. Nutrition reviews, 83(3), 422–447. https://doi.org/10.1093/nutrit/nuae184
The effect of prebiotics, alone or as part of synbiotics, on cardiometabolic parameters in women with polycystic ovary syndrome: a systematic review and meta-analysis of randomized controlled trials
Polycystic ovary syndrome (PCOS) is an endocrine disorder affecting women of reproductive age, characterized by irregular menstruation, hyperandrogenism, insulin resistance, and obesity. Current treatments for PCOS, such as oral contraceptive pills, primarily address symptoms of the condition rather than addressing the underlying causes. As a result, individuals with PCOS may seek alternative therapies. Given that gastrointestinal dysbiosis is common in PCOS, using prebiotics to help restore gut dysbiosis may offer a promising therapeutic approach. Razmpoosh et al. (2025) conducted a systematic review and meta-analysis to assess the effects of prebiotics or synbiotics on cardiometabolic markers in women aged 18 and over with diagnosed PCOS. A total of 20 randomized controlled trials sourced from PubMed, Scopus, ISI Web of Science, Embase, and the Cochrane Central Register of Controlled Trials were included in this study. Articles were included if they involved women diagnosed with PCOS receiving interventions with prebiotics and/or synbiotics. The prebiotics used in the selected articles included psyllium, inulin, FOS, and high-fiber-diets. The study reports high-quality evidence supporting the effects of prebiotics, either alone or as part of synbiotics, in reducing body mass index (BMI) and diastolic blood pressure (DBP) in women with PCOS. Moderate-quality evidence was reported for the effects of prebiotic interventions on body weight, waist-to-hip ratio, and triglycerides improvements, while low or very-low-quality evidence was reported for improvements in waist circumference, fat mass, fasting plasma glucose, fasting insulin, low-density lipoprotein, total cholesterol, high sensitive-C reactive protein, total testosterone, follicle-stimulating hormone, and free androgen index. Overall, this systematic review and meta-analysis highlights the potential of prebiotics, alone or as part of synbiotics, to improve various cardiometabolic markers, including BMI and DBP in women with PCOS. Further research is warranted to explore the effects on other metabolic and hormonal outcomes.
Key takeaways:
- PCOS is an endocrine disorder characterized by irregular menstruation, hyperandrogenism, insulin resistance, and obesity, affecting women of reproductive age.
- Supplementation with prebiotics and/or synbiotics in women diagnosed with PCOS may help improve cardiometabolic markers including BMI and DBP.
- Further research is needed to assess the effects of prebiotic supplementation in other outcomes among women with PCOS.
Access the study: https://www.mdpi.com/2227-9059/13/1/177
Reference: Razmpoosh, E., Sivanandy, M. S., & Ehrlich, A. M. (2025). The Effect of Prebiotics, Alone or as Part of Synbiotics, on Cardiometabolic Parameters in Women with Polycystic Ovary Syndrome: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Biomedicines, 13(1), 177. https://doi.org/10.3390/biomedicines13010177
Effect of probiotic and prebiotics supplementation on hemoglobin levels and iron absorption among women of reproductive age and children: a systematic review and meta-analysis
Nutritional anemia significantly impacts children and women of reproductive age (WRA), posing concerns for growth and cognitive performance development in children and risks on fetus development in WRA. Apte et al. (2025) conducted a systematic review and meta-analysis to assess the effects of supplementing with probiotics and prebiotics on markers of anemia such as iron absorption, hemoglobin, and ferritin levels in children and WRA. A total of 29 randomized controlled trials, including 15 in children and 14 in WRA, sourced from PubMed, Embase, and Cochrane Library were included in this meta-analysis. The major interventions used in the studies included GOS and inulin as prebiotics and heat-killed H61, Lactobacillus plantarum 299v, L. reuteri, and L. acidophilus as probiotics, where 14 of the studies used the pre and/or probiotics as supplements and 15 as fortificants to food items. Analysis of five studies showed that supplementing with prebiotics and/or probiotics with or without iron had little to no effect on hemoglobin levels in WRA, relative to placebo. Analysis of six other studies found that supplementation with prebiotics and/or probiotics with or without iron led to a significant increase in ferritin levels in WRA. Lp299v and GOS seemed to be the most promising in improving anemia markers in WRA. In studies involving children, eight of them did not report on any significant changes in hemoglobin, ferritin, or fractional iron absorption. Overall, supplementation with prebiotics/probiotics did not significantly improve any anemia markers among children but have some evidence supporting the improved ferritin levels among WRA. Further research is warranted to study different biotic formulations in these populations.
Key takeaways:
- Nutritional anemia is concerning because it can impact growth and cognitive development in children, as well as fetal development in WRA.
- Supplementation with prebiotics and/or probiotics did not significantly improve hemoglobin levels and iron absorption but significantly improved ferritin levels among WRA.
Access to the study: https://bmcnutr.biomedcentral.com/articles/10.1186/s40795-025-01015-3
Reference: Apte, A., Parge, A., Nimkar, R. et al. Effect of probiotic and prebiotics supplementation on hemoglobin levels and iron absorption among women of reproductive age and children: a systematic review and meta-analysis. BMC Nutr 11, 31 (2025). https://doi.org/10.1186/s40795-025-01015-3