Glucose- and glycaemic factor-lowering effects of probiotics on diabetes: a meta-analysis of randomised placebo-controlled trials
What this study found
Probiotic supplementation reduced fasting glucose by 0.52 mmol/L and HbA1c by 0.32 percentage points vs placebo. Insulin and HOMA-IR reductions were not significant overall. In participants with diabetes, probiotics significantly reduced glucose, HbA1c, insulin and HOMA-IR; in participants with risk factors only, no significant reductions were observed for glucose or HbA1c or HOMA-IR, with some insulin reductions in other subgroups. Capsule-form and multi-strain regimens yielded greater glucose reductions; milk-based forms were less effective. Dosage and duration showed no consistent…
- Study & population
- Eleven randomized, placebo-controlled trials (English-language, 2000–2015) including participants with diabetes or associated risk factors (overweight/obesity, hypertension, metabolic syndrome) across seven countries; total participants n=614; nine trials were double-blind and two were single-blind; blinded assessors used in all studies.
- Intervention
- Probiotic supplementation regimens varied across trials: single- and multi-strain formulations; delivered as capsules or dairy products (milk/yogurt); doses around ≥10^9 CFU per dose or <10^9; durations ranged from under 8 weeks to 8 weeks or longer; regimens included both capsule- and fermented-dairy–based delivery…
- Key limitation
- High heterogeneity across trials (glucose I2 = 94%, HbA1c I2 = 83%); varied strains, doses, delivery forms and durations; English-language only; insufficient data to isolate strain-specific effects; not all populations represented; long-term safety and efficacy remain uncertain.
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Open PDFOriginal abstract
Abstract This meta-analysis examined the effect of probiotics on glucose and glycaemic factors in diabetes and its associated risk factors. All randomised-controlled trials published in English in multiple databases from January 2000 to June 2015 were systematically searched. Only studies that addressed glucose- and glycaemic-related factors as outcome variables were included. The main outcomes of interest in trials were mean changes in glucose, HbA1c, insulin and homoeostasis model assessment-estimated insulin resistance (HOMA-IR). Using the Physiotherapy Evidence Database (PEDro) scale to assess the quality of studies, a total of eleven studies with 614 subjects were included. The pooled mean difference and effect size with a 95 % CI were extracted using a random-effect model. It was found that there are statistically significant pooled mean differences between the probiotics and the placebo-controlled groups on the reduction of glucose (−0·52 mmol/l, 95 % CI −0·92, −0·11 mmol/l; P=0·01) and HbA1c (−0·32 %, 95 % CI −0·57, −0·07 %; P=0·01). There was no statistically significant pooled mean difference between the probiotics and the placebo-controlled groups on the reduction of insulin (−0·48 µIU/ml, 95 % CI −1·34, 0·38 µIU/ml; P=0·27) and HOMA-IR (pooled effect of –0·44, 95 % CI −1·57, 0·70; P=0·45). Meta-regression analysis identified that probiotics had significant effects on reduction of glucose, HbA1c, insulin and HOMA-IR in participants with diabetes, but not in participants with other risk factors. The present meta-analysis suggested that probiotics may be used as an important dietary supplement in reducing the glucose metabolic factors associated with diabetes.