Fermented rhizome functional foods and postbiotic-associated multi-target anti-obesity mechanisms: A systematic review

Background Fermented rhizome functional foods, derived from species such as Curcuma longa , Zingiber officinale , and Panax notoginseng , have gained attention for their potential therapeutic effects in obesity management. We reviewed current literature to evaluate the efficacy of fermented rhizome postbiotics in preclinical obesity models, encompassing anti-adipogenic, thermogenic, gut microbiota-modulatory, and anti-inflammatory roles. This systematic review focused on fermentation organisms, dosages, and underlying mechanisms. Methods A comprehensive literature search was conducted across PubMed, Scopus, Web of Science, and Embase from inception until April 2026. Inclusion criteria were studies using in vivo or in vitro models assessing fermented rhizome effects on obesity-related outcomes with comparisons to control groups. A total of 10 studies were included. Study quality was assessed using SYRCLE's Risk of Bias Tool and ToxRTool. Results From 1307 studies retrieved, 10 met inclusion criteria across five rhizome species, fermented predominantly with Lactobacillus plantarum and Aspergillus oryzae . All eight in vivo studies reported reductions in body weight and improved lipid profiles. Fermented preparations consistently outperformed unfermented counterparts in all six direct comparisons. Gut microbiota analyses revealed enrichment of Akkermansia muciniphila and an improved Bacteroidetes / Firmicutes ratio. Six mechanistic axes were identified: adipogenesis suppression, AMPK–SIRT1–PGC-1α activation, gut microbiota–SCFA–brown adipose tissue thermogenesis, intestinal barrier reinforcement, inflammatory and ER stress attenuation, and appetite regulation. Conclusions Preclinical evidence, derived predominantly from in vivo diet-induced obesity models, complemented by in vitro mechanistic studies, suggests that fermented rhizome products may contribute to anti-obesity effects through multiple mechanisms. This evidence derives from studies with predominantly unclear-to-high risk of bias (SYRCLE assessment) and no clinical data, and should therefore be regarded as hypothesis-generating rather than directly translatable. Standardized protocols and clinical investigations are needed to confirm therapeutic potential in obesity management.