# Effects of probiotic supplementation on islet β-cell function in subjects with glucose metabolism disorders: a meta-analysis

## TL;DR

This study finds that probiotics may improve pancreatic β-cell function in people with glucose metabolism disorders, especially those with high HbA1c levels.

## Contribution

The study provides a meta-analysis showing probiotics may improve β-cell function in glucose metabolism disorders, particularly in those with high baseline HbA1c.

## Key findings

- Probiotic supplementation significantly improved HOMA-β in participants with baseline HbA1c ≥ 8.5%.
- Higher baseline HbA1c was positively associated with greater HOMA-β improvement.
- No significant effect was found in participants with HbA1c < 8.5%.

## Abstract

Islet β-cell dysfunction is central to the pathophysiology of glucose metabolism disorders. Probiotic supplementation has been shown to benefit glycemic control, but existing evidence on β-cell function remains inconclusive. This meta-analysis investigated the effects of probiotic supplementation on pancreatic islet β-cell function, as assessed by the homeostasis model assessment for β-cell function (HOMA-β), in individuals with impaired glucose metabolism.

A systematic search of PubMed, Embase, Web of Science, and the Cochrane Library was conducted. We included randomized controlled trials (RCTs) comparing probiotics with placebo or no additional treatment in adults with abnormal glucose metabolism. Random-effects meta-analysis was performed, accounting for the potential influence of heterogeneity.

Twelve RCTs involving 907 participants were included. Compared with controls, probiotic supplementation significantly improved HOMA-β (mean difference [MD]: 3.04, 95% CI: 0.23 to 5.86; p = 0.03; I2 = 92%). However, the sensitivity analysis limited to studies with low risk of bias did not show that probiotics have a significant influence on HOMA-β in these participants (MD: -1.31, 95% CI: −6.30 to 3.68, p = 0.61; I2 = 63%). Subgroup analysis showed a significant benefit in participants with baseline HbA1c ≥ 8.5% (MD: 7.05, 95% CI: 5.85 to 8.24; I2 = 0%), but not in those with HbA1c < 8.5% (MD: 0.19, 95% CI: −1.09 to 1.46; I2 = 37%; p for subgroup difference < 0.001). Meta-regression further confirmed that higher baseline HbA1c was positively associated with greater HOMA-β improvement (coefficient = 2.91; p = 0.04; adjusted R2 = 62.5%). Other factors, such as mean age, sex, baseline body mass index, HOMA-β, concurrent hypoglycemic treatment, or probiotic treatment duration, did not significantly affect the results.

Probiotics might enhance islet β-cell function in individuals with glucose metabolism disorders, particularly among those with elevated baseline HbA1c levels. However, large-scale high-quality RCTs are needed to validate our findings.

The protocol of the meta-analysis was registered at PROSPERO with the identifier CRD420251087101.