Resistant starch improves Parkinson’s disease symptoms through restructuring of the gut microbiome and modulating inflammation
Parkinson’s disease (PD) is the second most common neurodegenerative disorder globally, typically progressing slowly with early, non-motor symptoms such as constipation, loss of smell, and fatigue, and later developing into motor complications, bradykinesia, tremor, rigidity, postural instability, and dementia. Notably, the gut microbiome of both drug-naïve and treated PD patients is altered and exhibits a pro-inflammatory microbiome state, further promoting neuroinflammation. This single-centre, open-label, randomized, controlled trial investigated different nutritional interventions administered over a short-term (2 weeks) or long-term (48 weeks) supplementation period in patients with PD. Seventy-four patients were assigned to one of three treatment groups and followed either 1) a conventional diet, 2) a conventional diet with 15 g of type 3 resistant starch (RS) daily, or 3) a high-fibre diet. Stool and blood samples, as well as clinical, pharmacological, and nutritional data, were collected at baseline, week 1, and week 2. For patients receiving long-term treatment, these assessments were repeated bimonthly over a 48-week period, of which 40 weeks included treatment followed by an 8-week wash-out period. This study revealed that supplementation with RS increased Faecalibacterium species and short-chain fatty acids (SCFAs) alongside a reduction in opportunistic pathogens. On the metagenomic level, dietary intervention improves intracommunity signalling in the gut microbiome, which is shown to be altered in PD. Long-term supplementation also increased blood proteins apolipoprotin A-IV (APOA4) and heat shock protein family A (HSPA5), potentially mitigating PD-related neuroinflammation and alpha-synuclein toxicity. Future studies should confirm the effects of RS in PD in a blinded, placebo-controlled study design, while also stratifying participants based on their polygenic risk scores to PD.
Key Takeaways:
- PD is associated with alterations in the gut microbiome and highlights the potential for dietary interventions in mediating this disease.
- Supplementation with RS led to an increase in Faecalibacterium species and SCFAs alongside a reduction in opportunistic pathogens.
- Long-term supplementation with RS was associated with increased blood APOA4 and HSPA5 and reduced symptoms of PD.
- Blinded, placebo-controlled studies, with patients stratified according to polygenic risk scores for PD are needed to confirm these findings.
Access the study: https://doi.org/10.1016/j.bbi.2025.106217
Reference: Petrov, V., Schade, S., Laczny, C., Hallqvist, J., May, P., Jager, C., Aho, V., Hickl, O., Halder, R., Lang, E., Caussin, J., Lebrun, L., Schulz, J., Unger, M., Mills, K., Mollenhauer, B., & Wilmes, P. (2026). Resistant starch improves Parkinson’s disease symptoms through restructuring of the gut microbiome and modulating inflammation. Brain Behaviour and Immunity, 132 : 106217.
Tolerability and efficacy of an enteral formula containing partially hydrolyzed guar gum in patients following gastrointestinal surgery: A prospective, multicenter, open-label, randomized controlled study.
Malnutrition affects many surgical patients and is largely attributed to factors such as surgical trauma, stress, gastrointestinal insufficiency, and inadequate nutrition. The introduction of Enhanced Recovery After Surgery (ERAS) protocols has led to a paradigm shift in traditional perioperative management, underscoring the beneficial impacts of nutritional status in improving clinical outcomes. Partially hydrolyzed guar gum (PHGG) is a soluble dietary fiber with strong water-absorbing abilities and prebiotic properties. PHGG is also fermented by the gut microbiota, leading to beneficial health outcomes. The present study investigated the tolerance and clinical outcomes of an enteral formula supplemented with PHGG in 631 patients following gastrointestinal surgery. Patients were randomized to receive either a fiber-enriched formula containing 15 g/L PHGG, or a standard fiber-free formula (placebo) for 5 days. Data on feeding effectiveness, tolerability, and clinical outcomes was subsequently collected. Among patients that consumed ≥4500 kcal over 5 days (averaging 900 kcal/day), the PHGG group showed significantly improved feeding tolerance, with a reduced prevalence of diarrhea and abdominal distension compared to the placebo group. The PHGG group also demonstrated benefits in weight preservation at discharge and, 30 days after surgery, reported higher EuroQol-5 Dimension questionnaire scores, especially for pain/discomfort and anxiety. Additionally, patients with gastric cancer in the PHGG group had significantly less abdominal distension. Overall, the enteral formula containing the prebiotic PHGG was highly effective and well-tolerated among patients undergoing gastrointestinal surgery compared to previous postoperative formulas without dietary fiber. Future studies are warranted to validate the findings of this trial and to further investigate the mechanism of action.
Key Takeaways:
- Malnutrition resulting from gastrointestinal surgery is associated with a higher risk of postoperative complications, including higher rates of morbidity and mortality.
- Enteral formula supplemented with PHGG was well-tolerated and improved gastrointestinal symptoms in patients recovering from gastrointestinal surgery.
- Additional studies are warranted to confirm these results and clarify the mechanisms involved.
Access the study: https://pubmed.ncbi.nlm.nih.gov/41483486/
Reference: Han, T., Zhuo, J., Wu, X., Chi, Q., Chen, B., Chen, J., Chen, W., Jia, Z., Zhao, R., Zhang, X., Zhang, P., Mao, Y., Xu, X., Gao, Q., Shen, X., Sun, B., Guo, P., Wang, Z., Yang, J., & Qin, H. (2026). Tolerability and efficacy of an enteral formula containing partially hydrolyzed guar gum in patients following gastrointestinal surgery: A prospective, multicenter, open-label, randomized controlled study. Clinical Nutrition, 56: 106543.
Interindividual variability in gut microbiome mediates the efficacy of resistant starch on MASLD
Metabolic dysfunction-associated steatotic liver disease (MASLD) has a complex pathophysiology and significantly burdens affected individuals. RS was found to potentially decrease intrahepatic triglyceride content (IHTC) in MASLD, however interindividual variability in response to prebiotics has been highlighted in recent research. This randomized, placebo-controlled trial investigated the therapeutic effects of RS in MASLD and how baseline gut microbiota profiles influence individualized responses to RS interventions. Two hundred patients with MASLD were enrolled across three clinical centres and randomized to consume either 40 g/day of type 2 RS obtained from high-amylose maize or a control starch (CS) with equal energy content for 4 months. Patients receiving RS showed significant improvements in fatty liver and metabolic health after the 4-month intervention. Also, relative to CS, RS resulted in a 39.42% relative reduction of IHTC. Despite the overall effectiveness of RS, considerable heterogeneity in therapeutic response was observed. Of the 89 patients evaluated, 67 achieved a ≥30% relative reduction in IHTC, the threshold correlated with histological response and MASH resolution and were classified as high responders. The remaining 22 patients from this group were considered low responders. Although the low-responder group showed minimal differences in IHTC, significant improvements in adiposity, blood pressure, and alanine transaminase were still observed. High responders experienced these benefits to a greater effect, along with additional reductions in body weight, body mass index (BMI), insulin sensitivity, liver enzymes, blood pressure, and cytokeratin 18 levels. To validate these results, a single-arm, multi-centre clinical trial was then conducted using the same inclusion/exclusion criteria. In the second trial, 60 patients with MASLD underwent supplementation with RS for 4 months and reported that the overall relative decrease in IHTC among all patients was 31.08%. Notably, interindividual heterogeneity in therapeutic response to RS intervention was observed in this independent trial. Among the high responders in this trial, liver enzymes indicative of liver injury were reduced, and high-density lipoprotein cholesterol levels increased significantly. They also showed a significant reduction in liver stiffness measurements, suggesting improvement in liver fibrosis. Altogether, the heterogeneity in RS efficacy was observed across these two trials, as evidenced by the differential changes in steatosis, liver functions, adiposity-related parameters, and insulin sensitivity between low and high responders. Future research is warranted to confirm these findings and to elucidate the mechanisms underlying the difference between high and low responders.
Key Takeaways
- MASLD is a complex disease and is gaining increasing attention as a global health crisis.
- Intake of RS may decrease intrahepatic triglyceride content, however interindividual variability in response to prebiotics has recently been highlighted.
- Heterogeneity in RS efficacy was confirmed in two trials, with results differentiating patients as high or low responders.
Access the study: https://pubmed.ncbi.nlm.nih.gov/41270737/
Reference: Long, X., Wang, H., Lu, Y., Gao, X., Xiao, Y., Zhang, M., Guo, J., Yang, J., Zhang, R., Li, Q., Zhou G., Yang, R., Chen, F., Wu, Q., Sun, L., Chu, C., Zhu, X., Wu, Z., Ren, Q., You, C., Liu, Z., Li, Q., Liu, D., Cheng, D., Kang, P., Chen, A., Wu, Q., Fang, Q., Wei, L., Zhang, L., Li, J., Panagiotou, G., Jia, W., Zeng, R., Ni, Y., Chen, L., & Li, H. (2025). Interindividual variability in gut microbiome mediates the efficacy of resistant starch on MASLD. Cell Metabolism, 37, 2342-2361.
Standardized hibiscus-inulin shot lowers lipid-glucose indices in adults with overweight and obesity: 8-week randomized trial
Cardiometabolic disorders, including dyslipidemia, insulin resistance, and hypertension are major contributors to the global prevalence of chronic diseases and premature mortality. Functional foods that combine polyphenols and dietary fibers have been explored as nutritional interventions to target insulin signaling and lipid peroxidation pathways. This randomized, double-blind, placebo-controlled trial investigated the short-term changes in the Atherogenic Index of Plasma (AIP) and triglyceride-glucose index (TyG) in adults 18-50 years of age with a BMI ≥ 25 kg/m2 . One hundred participants were randomized to consume either 60 mL of a standardized hibiscus-inulin shot daily or a sensory-matched placebo for 8 weeks. The primary outcomes were AIP and TyG following the 8-week supplementation with the hibiscus-inulin shot, and secondary outcomes included mean arterial pressure (MAP) and pulse pressure (PP). Participants in the hibiscus-inulin shot group demonstrated significantly decreased AIP and TyG, compared to placebo. MAP and PP showed no significant differences between the groups, and effects were larger in high-risk baseline strata, indicating the initial cardiometabolic status influences the magnitude of response. Although there was a significant decrease in AIP/TyG in the hibiscus-inulin group, these findings reflect analytical responsiveness rather than clinical benefits. Future studies with longer follow-up periods, including metabolomic, microbiome, and vascular analyses, are warranted to confirm these baseline-dependent effects, and to define clinically meaningful thresholds for short-term changes in composite lipid-glucose indices.
Key Takeaways:
- Cardiometabolic disorders are a risk factor for premature mortality, and indices like AIP and TyG have gained attention as potential biomarkers for evaluating this risk.
- Consumption of a standardized hibiscus-inulin shot reduced AIP and TyG, while MAP and PP were unchanged, indicating a specific metabolic effect.
- Future studies are warranted to define clinically meaningful thresholds for short-term changes.
Access the study: https://doi.org/10.3390/nu17223556
Reference: Mendivil, E., Rivera-Iniguez, I., Arellano-Gomez, L., Martinez-Lopez, E., Hernandez-Guerrero, C., Sayago-Ayerdi, S., & Tejeda-Miramontes, J. (2025). Standardized hibiscus-inulin shot lowers lipid-glucose indices in adults with overweight and obesity: 8-week randomized trial. Nutrients, 17, 3556.
