Effects of inositols on adipokines: A systematic review of current knowledge and potential mechanisms

Inositols (INSs), carbocyclic sugar polyalcohols, are commonly used in obesity-related disorders. Adipokinesbioactive peptides secreted by adipocytes- may be released in obesity and excessive energy intake. The exact mechanism of INSs on adipokines is still unclear, although some studies have reported positive effects of supplementation with INSs. The present systematic review assessed the effects of INS supplementation on adipokine levels with a viewpoint of possible mechanisms of action. The search was conducted in PubMed/Medline, Scopus, Web of Science, and Google Scholar until September 2023. The evidence reviewed in this article illustrates that INSs increase insulin sensitivity by increasing leptin levels in the blood. Further, INSs may enhance leptin resistance by reducing leptin levels in the blood or up-regulating leptin receptors in the brain. Studies have shown that INS derivatives increase adiponectin levels, which in turn decrease obesity. The effects of INSs (in different isomers) on other adipokines such as resistin, ghrelin, and fibroblast growth factors (FGFs) are contradictory. In conclusion, the current body of evidence suggests marginal positive effects of INS supplementation on leptin and adiponectin, as the main adipokines involved in energy homeostasis and insulin-mediated functions. Further cellular, animal, and clinical trial studies are needed to assess the exact pharmacological effects of INSs on adipokines with a focus on involved molecular pathways.