Lactiplantibacillus plantarum J26 supplementation improves adiposity-related outcomes in adults with metabolic syndrome via remodeling the gut microbiota

Preclinical studies have shown that Lactiplantibacillus plantarum J26 (J26) improves metabolic syndrome (MetS)-related parameters, but clinical evidence remains limited. We therefore conducted a 12-week randomized, double-blind, placebo-controlled trial in 110 adults with MetS, who received J26 (5 × 10⁹ CFU/day) or placebo (ChiCTR2400088192). Compared with placebo, J26 significantly reduced body weight (−0.75 kg, P = 0.021), BMI (−0.29 kg/m², P = 0.021), waist circumference (−1.92 cm, P = 0.023), and body fat (−0.87%, P = 0.003), and enriched Lactobacillus and Bifidobacterium , which partially mediated reductions in adiposity-related outcomes. Although effects on blood pressure, glycemic, and lipid parameters were limited, exploratory clustering identified heterogeneous metabolic responses; responders showed greater metabolic improvements, enrichment of Lactobacillus , Bacteroides , and Anaerobutyricum , and higher baseline dietary quality than non-responders. However, these exploratory, hypothesis-generating findings require further validation. J26 may improve adiposity-related outcomes partly through gut microbiota remodeling, while baseline dietary quality may contribute to heterogeneity in broader metabolic benefits.