turmeric as a gut-microbiota modulator for cardio-metabolic risk factors: an updated comprehensive review

Turmeric is a medicinal herb with antioxidant and anti-inflammatory components that can affect metabolic parameters via various pathways, including the gut-brain axis. although positive effects of turmeric on health have been reported, findings are conflicting. accordingly, the current review aimed to provide an overview of the biochemical and biological characteristics of turmeric and examine the impacts of turmeric on cardio-metabolic risk factors with a special focus on its abilities to modulate gut microbiota. in the present comprehensive review, findings of systematic reviews/narrative reviews, clinical trials, animal, and in vitro studies on turmeric in the english language published between 2010 and march 2023 were summarized. findings revealed that turmeric is a safe medicinal herb with mild gastrointestinal side effects in some cases. it can help improve the glycemic status, lipid profile, and blood pressure. however, food processing and fermentation can affect the bioavailability of its effective components, including curcumin. several mechanisms, including those affecting intestinal microbiota diversity, intestinal permeability, inflammatory and oxidative pathways, are proposed for their positive effects on metabolic factors.   however, due to high between-study heterogeneity, limited high-quality clinical trials, differences in the duration of the intervention, and the form of turmeric supplement, more studies on each metabolic parameter are needed to determine effective dosages and confirm its efficacy as a complementary therapy to modulate microbiota and cardio-metabolic parameters.