Glucose- and glycaemic factor-lowering effects of probiotics on diabetes: a meta-analysis of randomised placebo-controlled trials

Study answer

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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Original abstract