Synbiotics protected radiation-induced tissue damage in rectal cancer patients: A controlled trial
Rectal cancer patients commonly receive radiotherapy (RT) as a crucial adjunct part of their treatment plan. RT is either used preoperatively (neoadjuvant) or postoperatively (adjuvant). Despite its usefulness for improving oncological outcomes by reducing local recurrences or downstaging tumors, RT often causes significant gastrointestinal side effects, including abdominal pain, bleeding, and bowel dysfunction, as well as tissue injury. As such, preventative measures may be taken before the damage occurs. This randomized, controlled trial investigated the effects of a prebiotic and a synbiotic on mitigating RT-induced gut injury by modulating the mucosa-associated microbiota, reducing inflammation, and enhancing gut barrier function in patients undergoing RT for rectal cancer. Thirty patients diagnosed with rectal adenocarcinoma and scheduled for preoperative short-term RT were randomized into three groups (10 participants/group): a control group, a prebiotic group receiving 45 g oat bran (8 g of dietary fiber, 4.5 g of β-glucan), and a synbiotic group receiving 22 g oat bran (4 g dietary fiber) with 1010 colony forming units (CFU)/g of Lactobacillus plantarum HEAL19 and 13 g freeze dried blueberry husks (4 g dietary fiber). The patients ingested the study interventions daily for two weeks, starting one week before RT and one week during RT. Fecal, blood, and biopsy samples were collected before and after RT to evaluate the inflammatory markers, intestinal permeability, histopathological changes, and mucosa-associated microbiota. While a significant reduction was reported in white blood cell counts following RT in both the prebiotic and synbiotic groups, and no significant change was reported in the control group, no significant difference was found in white blood cell counts among the three groups. Histopathological analysis revealed reduced inflammation and fibrosis in the synbiotics group compared to the other two groups. Despite the decrease in bacterial diversity caused by RT, the synbiotics group showed a greater proportion that was preserved, with a 25.1% reduction compared to a 55.4% reduction in the prebiotic group. Future trials should investigate longer treatment durations.
Key takeaways:
- RT is a common treatment plan for colorectal cancer, downsizing the tumor and reducing local cancer recurrence.
- Despite its benefits, patients receiving RT regularly experience gastrointestinal side effects and tissue injury at the irradiated site.
- The study explored the effects of prebiotic and synbiotic use in improving RT-induced gut injury, including inflammation and gut barrier function.
- Synbiotics had better outcomes on protecting the rectal mucosa by reducing inflammation and modulating mucosa-associated microbiota, despite the effects being primarily localized, which reflects the short-term duration of the treatment.
Access the study: https://pubmed.ncbi.nlm.nih.gov/40250086/
Reference: Stene, C., Xu, J., Fallone de Andrade, S., Palmquist, I., Molin, G., Ahrné, S., Thorlacius, H., Johnson, L. B., & Jeppsson, B. (2025). Synbiotics protected radiation-induced tissue damage in rectal cancer patients: A controlled trial. Clinical nutrition (Edinburgh, Scotland), 49, 33–41. https://doi.org/10.1016/j.clnu.2025.03.025
The effects of prebiotic supplementation on markers of exercise-induced gastrointestinal syndrome in response to exertional heat stress
Exercise-induced gastrointestinal syndrome (EIGS) refers to the changes in gastrointestinal integrity and function leading to gastrointestinal symptoms (GIS) in response to exercise. Several pathophysiological changes have been associated with EIGS, including intestinal epithelial cell injury with subsequent increased permeability and altered enteric nervous activity affected by functional impairments in motility, digestion, and nutrient absorption. GIS has been linked to the occurrence of these changes in response to exercise stress. Research on biotics, specifically synbiotics and probiotics, has shown their potential for attenuating or even preventing EIGS and associated GIS by supporting the increase in the relative abundance of short-chain fatty acid-producing commensal bacteria. These microorganisms enhance mucosal lining, functional capabilities, and immune regulation. As such, this randomized, double-blind, parallel study investigated the impact of daily prebiotic supplementation on gastrointestinal integrity and functional status markers of EIGS and GIS in response to exertional heat stress (EHS). Sixteen endurance athletes completed two trials of EHS, involving 3-hour running in 30 °C conditions, before and after the 8-week supplementation period. Participants received either 16 g/day of a prebiotic blend (guar gum, inulin-type fructans, resistant starch, and β-GOS) or placebo (maltodextrin). The study measured markers such as intestinal fatty acid-binding protein (I-FABP) for epithelial injury, soluble CD14 for bacterial endotoxemia, and other systemic inflammatory markers, as well as GIS and orocecal transit time. Results showed that prebiotic supplementation significantly blunted the increase in I-FABP and reduced sCD14 levels. However, no differences were observed in orocecal transit time, feeding tolerance, or GIS. Altogether, these findings suggest that 8-week prebiotic supplementation modestly attenuates EHS-associated intestinal integrity perturbations, without exacerbating EHS-associated GIS or impairing transit time or feeding tolerance.
Key takeaways:
- EIGS involves gastrointestinal barrier disruptions during strenuous exercise, which can lead to increased intestinal permeability and systemic inflammatory responses.
- The study assessed the effects of daily prebiotic supplementation (16 g/day) for eight weeks on protecting against EIGS and GIS during prolonged exertional heat stress in endurance athletes.
- Prebiotics significantly reduced post-exercise increases in I-FABP and reduced sCD14, indicating improved intestinal integrity without worsening GIS, but showed no effects on transit time or feeding tolerance.
Access the study: https://pubmed.ncbi.nlm.nih.gov/40010361/
Reference: Rauch, C. E., Henningsen, K., Martinez, I., Young, P., Mika, A., Huschtscha, Z., McCubbin, A., Henry, R., Anderson, D., & Costa, R. J. S. (2025). The Effects of Prebiotic Supplementation on Markers of Exercise-Induced Gastrointestinal Syndrome in Response to Exertional Heat Stress. International journal of sport nutrition and exercise metabolism, 35(4), 273–290. https://doi.org/10.1123/ijsnem.2024-0127
A gut-focused perinatal dietary intervention is associated with lower alpha diversity of the infant gut microbiota: results from a randomised controlled trial
Preclinical data have demonstrated a relationship between maternal prenatal diet, such as high-fat or low-fiber, and the maternal and offspring gut microbiota, which remains to be confirmed in humans. Observational studies in humans support this concept, showing relationships between the maternal prenatal diet and an infant’s gut microbial composition. This randomized, controlled trial investigated the effects of a gut-focused perinatal dietary intervention on maternal and infant gut microbiota composition four weeks after birth. Forty-four pregnant women were enrolled in the study, receiving dietary advice as part of standard care or a dietary intervention focused on the Australian Dietary Guidelines, aimed at increasing consumption of prebiotic, probiotic, and fermented foods. Maternal fecal samples were collected at 26 weeks of gestation (baseline), and both maternal and infant fecal samples were collected at four weeks postpartum (follow-up). All samples underwent 16S rRNA sequencing. The study’s primary outcome was between-group differences in infant fecal Shannon index of α-diversity. Secondary outcomes included between-group differences at follow-up in microbiota measures, including inverse Simpson index, observed species count, phylogenetic diversity, community dissimilarity, and differential amplicon sequence variant abundance, including Prevotella abundance. Maternal between-group changes from baseline were investigated for the same outcomes. Forty-five infants to the 44 mothers were included in the study. The mean Shannon index of infants in the intervention group was -0.35 units lower than that of the control group infants, corresponding to a medium effect size. Metrics of α-diversity were similar, and no between-group differences were reported in the β-diversity, nor any differentially abundant taxa in infants. Nonetheless, an increase was reported in Prevotella abundance in mothers in the intervention group compared to the control group. The study did not meet the recruitment target and was underpowered. Larger studies are needed to investigate these findings.
Key takeaways:
- There is limited human clinical data on the relationship between maternal prenatal diet and infant gut microbiome composition, which is seen in preclinical settings.
- This study recruited pregnant mothers prior to and following delivery, along with their offspring, to investigate the effects of a gut-focused perinatal dietary intervention compared to a control standard of care.
- At follow-up, the mothers in the intervention group showed a higher Prevotella abundance, and the infant’s α-diversity was lower than that of the control group subjects.
- Future larger studies are required to investigate the possible clinical implications of the study’s reported findings.
Access the study: https://pubmed.ncbi.nlm.nih.gov/39422256/
Reference: Dawson, S. L., Clarke, G., Ponsonby, A. L., Loughman, A., Mohebbi, M., Borge, T. C., O’Neil, A., Vuillermin, P., Tang, M. L. K., Craig, J. M., & Jacka, F. N. (2025). A gut-focused perinatal dietary intervention is associated with lower alpha diversity of the infant gut microbiota: results from a randomised controlled trial. Nutritional neuroscience, 28(6), 694–708. https://doi.org/10.1080/1028415X.2024.2413233
The impact of an acute high polyphenol, high fiber meal with and without aerobic exercise on metabolism in middle-aged and older adults: A pilot study
Cardiovascular and metabolic diseases are highly prevalent worldwide, leading to morbidity and mortality. These conditions are largely affected by contemporary dietary patterns and physical inactivity. In middle-aged and older adults, a high-fat, high carbohydrate (HFHC) meal can induce adverse effects on triglyceride (TRG), glucose, and metabolic load index (MLI; TRG + glucose). This randomized, crossover study investigated the potential benefits of a high polyphenol, high fiber meal with or without exercise on postprandial TRG, glucose, and MLI in middle-aged and older adults. Ten healthy adults (6 females, 4 males) completed four experimental conditions: 1) traditional HFHC, 2) traditional HFHC + exercise, 3) HFHC meal with polyphenols and fiber (P-HFHC), and 4) P-HFHC + exercise. The participants consumed meals providing 12 kcal/kg of body mass, followed by 30 minutes of exercise designed to expend 25% of the consumed kcals. Measures of TRG and glucose were taken over 6 hours post-meal, and MLI was calculated. The study reported a significant time and condition interaction for postprandial TRG, glucose, and MLI. Significantly lower TRG was reported with the P-HFHC condition at 4 and 5 hours (p=0.031 and p=0.050, respectively) compared to the traditional HFHC. Postprandial glucose responses varied significantly across conditions and time points. P-HFHC reported a significantly lower glucose level compared to traditional HFHC at 30 minutes (p=0.016). However, at 1 hour postprandially, both P-HFHC and traditional HFHC reported significantly higher glucose levels than the exercise conditions (traditional HFHC + exercise and P-HFHC + exercise, all p < 0.050). At 2 hours postprandially, both the traditional HFHC and P-HFHC conditions reported significantly lower glucose levels compared to the exercise conditions (all p < 0.010). Then at 4 hours, the traditional HFHC alone and traditional HFHC + exercise conditions reported significantly higher glucose levels than the P-HFHC alone and the P-HFHC + exercise (p < 0.050). For MLI, both the P-HFHC and P-HFHC + exercise conditions reported significantly lower levels compared to traditional HFHC at 4 hours (p=0.020 and p=0.049, respectively). At 5 hours, the P-HFHC condition remained significantly lower (p=0.035). Altogether, these findings suggest that acute exercise and dietary strategies such as polyphenols and fiber that are minimally processed may reduce cardiovascular risk in middle-aged and older adults.
Key takeaways:
- Cardiovascular and metabolic conditions are highly prevalent worldwide, contributing to increased cases of morbidity and mortality, especially among middle-aged and older adults.
- The prevalence of disease is affected by contemporary dietary behaviours and sedentary lifestyles.
- This study investigated the effects of a high-polyphenol, high-fiber meal, with or without 30-minute post-meal exercise, on postprandial glucose, TRG, and MLI compared to a traditional high-fat, high-carb meal.
- The study emphasized that incorporating minimally processed, high-fiber, polyphenol-rich meals along with acute post-meal exercise routines could be a practical strategy for improving metabolic health and cardiovascular risk in middle-aged and older adults.
Access to the study: https://pubmed.ncbi.nlm.nih.gov/40443047/
Reference: Ater, L. J., Plantz, E. K., Manning, T. D., Akers, J. D., Edwards, E. S., & Kurti, S. P. (2025). The impact of an acute high polyphenol, high fiber meal with and without aerobic exercise on metabolism in middle-aged and older adults: A pilot study. Physiological reports, 13(11), e70312. https://doi.org/10.14814/phy2.70312
