The impact of probiotics or synbiotics on individuals with type 1 diabetes mellitus (T1DM): a systematic review and meta-analysis
- 1School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
- 2Student Research Committee (SRC), Tehran University of Medical Sciences, Tehran, Iran
- 3Clinical Education Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
Abstract
Introduction: Type 1 Diabetes Mellitus (T1DM) is a chronic autoimmune condition characterized by insulin deficiency. Probiotics and synbiotics are believed to impact glycemic control. This study aims to evaluate their effects on individuals with T1DM.
Methods: A systematic search was conducted from inception to January 2026 in Cochrane Central, Web of Science, Scopus, and PubMed, with additional screening of gray literature and reference lists. Randomized controlled trials evaluating probiotics or synbiotics in individuals with type 1 diabetes mellitus (T1DM) were included. Risk of bias was assessed using the Cochrane ROB-2 tool. Data were synthesized using weighted mean difference (WMD) with 95% confidence intervals under a random-effects model in STATA-17. Subgroup, sensitivity, and publication bias analyses were also performed.
Results: From 2,722 records, 10 randomized controlled trials were included. Meta-analysis showed that probiotics or synbiotics significantly reduced HbA1c (WMD = -0.58%, 95% CI [-1.00, -0.17]) and fasting blood sugar (WMD = -43.34 mg/dL, 95% CI [-81.71, -4.96]) compared with controls. No significant effects were observed for C-peptide (WMD = -0.03 ng/mL, 95% CI [-0.11, 0.05]) or insulin requirement (WMD = -0.09 U/kg/day, 95% CI [-0.19, 0.01]). A significant reduction was found in total cholesterol (WMD = -7.92, 95 mg/dL CI [-15.73, -0.12]), whereas no significant changes were found for CRP, TG, HDL, LDL, or TNF-α.
Conclusion: Probiotics or synbiotics may improve glycemic control in T1DM, particularly by reducing HbA1c and fasting blood sugar. The observed HbA1c improvement may be clinically meaningful if sustained. However, evidence for effects on beta-cell function, insulin requirement, inflammatory markers, and most lipid outcomes remains limited. Larger, high-quality trials with standardized interventions are needed to confirm these findings.
Clinical trial number: Not applicable.
Supplementary Information: The online version contains supplementary material available at https://doi.org/10.1186/s12902-026-02453-1.
Related
- A Systematic Review of The Role of Probiotics and Synbiotics on Semen Quality and Sperm Function in Male Infertility
- Association of small nerve fiber dysfunction on pain characteristics in type 2 diabetes mellitus individuals with chronic low back pain
- Ultrasound Evaluation of Lower-Limb Arterial Morphology and Hemodynamics in Type 2 Diabetes Mellitus Versus Non-Diabetic Controls: A Systematic Review and Meta-Analysis
- Effects of Metformin on Clinical Outcomes After Acute Ischemic Stroke in Patients with Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis
- Adherence to the EAT-Lancet reference diet and risk of diabetes mellitus: a systematic review and dose-response meta-analysis of prospective studies
BibTeX
@article{sohrabizadeh2026impact,
title = {{The impact of probiotics or synbiotics on individuals with type 1 diabetes mellitus (T1DM): a systematic review and meta-analysis}},
author = {Sina Sohrabizadeh and Mehrad Namazee and Mohammad Erfan Lotfi and Seyed Amirhossein Tabatabaei and Saghar Elmi and Jeyran Ostovarfar},
journal = {BMC Endocrine Disorders},
year = {2026},
month = aug,
doi = {10.1186/s12902-026-02453-1},
url = {https://doi.org/10.1186/s12902-026-02453-1},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - The impact of probiotics or synbiotics on individuals with type 1 diabetes mellitus (T1DM): a systematic review and meta-analysis
AU - Sina Sohrabizadeh
AU - Mehrad Namazee
AU - Mohammad Erfan Lotfi
AU - Seyed Amirhossein Tabatabaei
AU - Saghar Elmi
AU - Jeyran Ostovarfar
PY - 2026
DA - 2026/08/07
JO - BMC Endocrine Disorders
DO - 10.1186/s12902-026-02453-1
UR - https://doi.org/10.1186/s12902-026-02453-1
AB - Introduction: Type 1 Diabetes Mellitus (T1DM) is a chronic autoimmune condition characterized by insulin deficiency. Probiotics and synbiotics are believed to impact glycemic control. This study aims to evaluate their effects on individuals with T1DM. Methods: A systematic search was conducted from inception to January 2026 in Cochrane Central, Web of Science, Scopus, and PubMed, with additional screening of gray literature and reference lists. Randomized controlled trials evaluating probiotics or synbiotics in individuals with type 1 diabetes mellitus (T1DM) were included. Risk of bias was assessed using the Cochrane ROB-2 tool. Data were synthesized using weighted mean difference (WMD) with 95% confidence intervals under a random-effects model in STATA-17. Subgroup, sensitivity, and publication bias analyses were also performed. Results: From 2,722 records, 10 randomized controlled trials were included. Meta-analysis showed that probiotics or synbiotics significantly reduced HbA1c (WMD = -0.58%, 95% CI [-1.00, -0.17]) and fasting blood sugar (WMD = -43.34 mg/dL, 95% CI [-81.71, -4.96]) compared with controls. No significant effects were observed for C-peptide (WMD = -0.03 ng/mL, 95% CI [-0.11, 0.05]) or insulin requirement (WMD = -0.09 U/kg/day, 95% CI [-0.19, 0.01]). A significant reduction was found in total cholesterol (WMD = -7.92, 95 mg/dL CI [-15.73, -0.12]), whereas no significant changes were found for CRP, TG, HDL, LDL, or TNF-α. Conclusion: Probiotics or synbiotics may improve glycemic control in T1DM, particularly by reducing HbA1c and fasting blood sugar. The observed HbA1c improvement may be clinically meaningful if sustained. However, evidence for effects on beta-cell function, insulin requirement, inflammatory markers, and most lipid outcomes remains limited. Larger, high-quality trials with standardized interventions are needed to confirm these findings. Clinical trial number: Not applicable. Supplementary Information: The online version contains supplementary material available at https://doi.org/10.1186/s12902-026-02453-1.
SN - 1472-6823
ER -