3 New Papers: Gut Bugs Predict T2D Decades Out, Isometric Exercise Falls Short for Tendon Pain, Liraglutide Boosts Sleep Quality

Today's three picks span a large Swedish metagenomics cohort tracking who develops type 2 diabetes based on gut bacteria; a systematic review that quietly deflates the hype around isometric exercise for tendon injuries; and a Phase IV trial showing that liraglutide — a GLP-1 drug — meaningfully improves sleep quality as a secondary benefit in people with obesity.

Paper: Toubon G et al. "Gut microbiome composition and functional potential associate with incident type 2 diabetes in 4,685 adults from a Swedish prospective cohort." Cell Reports Medicine. 2026 May 27. PMID: 42202790. DOI: 10.1016/j.xcrm.2026.102835 1

Study design: Prospective cohort (SIMPLER study, Sweden). Shotgun metagenomic sequencing of stool from 4,685 older adults (mean age 73.9 years; 49% women), followed for a median of 5.3 years. 383 participants developed type 2 diabetes during follow-up.

Core finding: Researchers identified six gut bacterial species associated with higher T2D risk — including Desulfovibrio piger, several Alistipes species, and Ruminococcus gnavus — and three species linked to lower risk. A notable wrinkle: Akkermansia muciniphila, widely marketed for its gut-health benefits, was associated with increased T2D risk in this cohort — but only when dietary fiber intake was low. When fiber intake was high, the risk association essentially disappeared, suggesting its effect is diet-dependent. At the metabolic level, a gut pathway for asparagine degradation was linked to higher risk, while mannose degradation and the non-oxidative pentose phosphate pathway were protective.

Conflicts of interest: None declared.

Actionable takeaway: The Akkermansia finding is the signal most worth holding. Probiotic supplements containing A. muciniphila are growing in popularity, but this large prospective study suggests that whether it's protective or harmful may depend heavily on how much dietary fiber you're eating. Until your diet is genuinely high in fiber (from vegetables, legumes, and whole grains), the net benefit of an Akkermansia supplement is uncertain. For everyone: eating enough dietary fiber remains the most evidence-grounded lever for a gut microbiome profile associated with lower T2D risk.

Paper: Soliman EFF et al. "Isometric Exercises for Tendinopathies: A Systematic Literature Review." Clinical Therapeutics. 2026 May 27. PMID: 42203537. DOI: 10.1016/j.clinthera.2026.04.027 2

Study design: Systematic review of 13 randomized controlled trials (n = 336 participants; 40% female). Tendon sites included patellar, Achilles, lateral elbow (tennis elbow), rotator cuff, wrist extensor, and gluteal tendons. Median symptom duration was 23 months. Reviewed by researchers at University Hospitals Coventry & Warwickshire and King's College London.

Core finding: Isometric holds — sustained muscle contractions with no joint movement — have been championed in sports medicine for their rapid pain-relieving effects in tendinopathy. This review of 13 RCTs finds that statistically significant pain reduction and functional improvement were documented in only 3 of those trials. Adherence started near 100% but dropped over time. Crucially, 10 of 13 studies were rated as poor methodological quality; only 3 were rated good. The evidence does not establish isometric exercise as superior to eccentric or isotonic protocols for managing tendon pain across common sites.

Conflicts of interest: None declared.

Supervised tendon loading with resistance bands — the kind of eccentric and isotonic exercise the new review found better-supported than isometrics alone. Photo: Kaboompics / Pexels

Actionable takeaway: Isometric holds are still worth trying — they appear safe, pain-free enough to maintain adherence early on, and may offer short-term relief during flares when loading a tendon dynamically is too painful. But they should not replace a full tendon-loading program. If you have chronic Achilles, patellar, or rotator cuff tendinopathy and have relied solely on isometrics for months without meaningful improvement, this review supports escalating to a supervised eccentric or heavy slow-resistance protocol. The evidence base for isometrics as a standalone long-term solution is weak.

Paper: Behuhuma N et al. "Efficacy and acceptability of liraglutide for obesity in people with HIV: results of an open-label clinical trial in South Africa." Clinical Infectious Diseases. 2026 May 28. PMID: 42203210. DOI: 10.1093/cid/ciag337 3

Study design: Phase IV, open-label RCT (LIROH trial). 40 adults with HIV and BMI ≥ 30 kg/m² enrolled in KwaZulu-Natal, South Africa (May–September 2024). Liraglutide 3.0 mg daily for 12 weeks, plus lifestyle counselling. 38 of 40 participants (95%) completed the trial.

Core finding: Over 12 weeks, liraglutide produced substantial reductions in weight (−2.9%), waist circumference (−5.6 cm), and HbA1c (−0.3%). Beyond metabolic markers, sleep quality, depressive symptoms, and psychological quality of life all improved significantly during treatment. When liraglutide was stopped at 12 weeks, weight and waist circumference rebounded significantly by 24 weeks — but crucially, the improvements in sleep quality, depression, and QoL also largely disappeared, suggesting these benefits were mediated by the drug and/or associated weight loss rather than being durable lifestyle changes.

Sleep quality improvement was a secondary finding in the 12-week liraglutide trial — and reversed after the drug was stopped. Photo: Wings Panic / Pexels

Note: No conflict-of-interest statement was provided in the abstract. The trial was conducted by the African Health Research Institute (AHRI, South Africa) and Massachusetts General Hospital. Liraglutide (Saxenda/Victoza) is a Novo Nordisk product; no industry funding was declared.

Actionable takeaway: If you are managing obesity and experiencing poor sleep quality, the link between GLP-1 receptor agonist therapy and meaningful sleep improvement now has direct RCT support — albeit in a specific population. This study was conducted in people with HIV and obesity, so generalizability to the general population requires caution. That said, the pattern is consistent with broader literature suggesting that weight reduction via GLP-1 therapy reduces sleep apnea risk and improves sleep architecture. For anyone on a GLP-1 drug primarily for weight loss, tracking sleep quality as a secondary outcome is increasingly evidence-justified.