Effects of Plant Polyphenols on Obesity-Induced Inflammatory Depression: A Review

Epidemiological and clinical evidence indicates that obesity-associated metabolic dysfunction increases the risk of depression, which is often resistant to conventional antidepressant therapies. Elucidating targeted mechanisms underlying obesity-related depression is therefore essential for developing effective interventions. Accumulating evidence identifies neuroinflammation as a central link between obesity and depressive disorders. Obesity-driven inflammatory signaling disrupts multiple neurobiological processes implicated in depression, thereby contributing to the onset and progression of inflammatory depression. Polyphenols, a diverse class of plant-derived secondary metabolites, have demonstrated neuroprotective properties, attributed to their anti-inflammatory, antioxidant, and metabolic regulatory effects. By restoring neurobiological homeostasis, polyphenols may represent a promising therapeutic strategy for obesity-related inflammatory depression. This review summarizes the pathophysiological mechanisms through which obesity induces neuroinflammation and subsequently promotes depressive symptoms. It further evaluates current evidence regarding the efficacy and effective dosing of polyphenols in attenuating inflammatory signaling and alleviating obesity-related inflammatory depression, as well as the translational challenges faced in their clinical application. Given their anti-neuroinflammatory potential, polyphenols may serve as a valuable adjunctive approach for the management of obesity-related inflammatory depression.