Gut & Microbiome

1. Gut & Microbiomewell supported · human dataAdded 6 August 2026

   Probiotics shifted PCOS blood sugar, not the scales

   Pooling 8 randomised trials in women with polycystic ovary syndrome, probiotic or synbiotic supplements produced small reductions in fasting blood sugar (-2.52 mg/dl), insulin (-2.27 uIU/mL), HOMA-IR (-0.69), C-reactive protein and total testosterone (-0.12 ng/mL). Weight and body mass index did not change significantly.

   ⚠What it shows: Meta-analysis of only 8 RCTs (nine treatment arms) in women with polycystic ovary syndrome, searched to September 2018. The individual trials were small and short, effect sizes are modest, strains and doses varied between studies, and the findings do not transfer to women without PCOS.Meta-analysis · Eur J Clin Nutr

   Full breakdown →Insulin sensitivity explained →Metabolic Fitness Index →Effect of probiotics and synbiotics on selected anthropometric and biochemical measures in women with polycystic ovary syndrome: a systematic review and meta-analysis. Eur J Clin Nutr 2020
2. Gut & Microbiomepreliminary · human dataAdded 30 July 2026

   Bacteria grown from your own gut nudged metabolic markers

   In a 50-person pilot trial in people with metabolic syndrome, a 20-day course of "autoprobiotics", bacteria grown from each patient's own gut Enterococcus strains, reduced obesity measures, lowered glucose and HbA1c and left lower HbA1c and triglycerides than the nutritional mix alone by day 28, alongside larger shifts in gut bacteria.

   ⚠What it shows: A single 20-day pilot RCT in 50 adults aged 42-63 with metabolic syndrome (26 treated, 24 control) at one Russian centre, with short follow-up to day 28 and many microbiome outcomes reported, and the personalised strains are not an off-the-shelf product.RCT · Nutrients

   Full breakdown →Metabolic syndrome explained →Metabolic Fitness Index →Autoprobiotic Supplements Attenuate Obesity and Improve Gut Microbiota, Carbohydrate, and Lipid Metabolism in Patients with Metabolic Syndrome: A Pilot Trial. Nutrients 2026
3. Gut & Microbiomepreliminary · human dataAdded 29 July 2026

   Probiotic brain effects lingered weeks after stopping

   In a small trial of 32 healthy older adults, some brain effects of a six-week probiotic, differences in resting-state functional connectivity and in anxiety and depression scores, were still detectable 4-6 weeks after intake stopped, while other changes had faded. The persistent differences appeared between the two probiotic formulations rather than against baseline.

   ⚠What it shows: Exploratory follow-up of one randomised, blinded, placebo-controlled trial in 32 self-reported healthy older adults (mean age 68.0 years); only 8 to 12 participants per group were analysed out of about 30 randomised each, brain function was an exploratory outcome of the parent study, and psychological measures were exploratory throughout.Study · Commun Med (Lond)

   Full breakdown →Probiotic effects on brain health are both transient and sustained for several weeks after discontinuation: a randomised controlled trial. Commun Med (Lond) 2026
4. Gut & Microbiomepreliminary · human dataAdded 27 July 2026

   Gut bacteria before a diet predicted who stayed well

   In a microbiome analysis of adults with mild-to-moderate Crohn's disease on the Crohn's disease exclusion diet, those who sustained remission at both weeks 12 and 24 had a distinct gut profile at baseline, lower alpha diversity and more Alistipes and Faecalibacterium, while Haemophilus and Prevotella were negatively linked to remission.

   ⚠What it shows: Secondary microbiome analysis of two randomised trials, one in adults and one in children, with no sample size given for the remission comparison; associations between baseline bacteria and later remission are correlational and need prospective validation.Study · Crohns Colitis 360

   Full breakdown →Microbial predictors of sustained clinical remission following the Crohn's disease exclusion diet in adults and microbiome shifts toward healthy pediatric controls. Crohns Colitis 360 2026
5. Gut & Microbiomepreliminary · human dataAdded 26 July 2026

   Probiotics and depression: mostly null results

   Pooling 27 randomised trials, probiotics showed no significant effect on depressive symptoms over short (under 6 weeks) or medium (6-12 weeks) durations, with a significant benefit appearing only in a long-duration subgroup of just 2 studies. Prebiotics and postbiotics showed no clear effects.

   ⚠What it shows: Systematic review and meta-analysis of 27 RCTs published 2016-2024, but the only significant signal rests on 2 long-duration trials; substantial heterogeneity across studies and overall certainty rated moderate for inconsistency.Review · Nutr Neurosci

   Full breakdown →Efficacy of prebiotics, probiotics, and postbiotics on depression: a systematic review and meta-analysis of randomized controlled trials. Nutr Neurosci 2026

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