Curcumin Supplementation Reduces Inflammation, Neutrophil-to-Lymphocyte Ratio (NLR), and Antioxidant Status in Obese Patients with Type 2 Diabetes: A Randomized Controlled Trial

Type 2 diabetes mellitus (T2DM) is a chronic metabolic disorder characterized by insulin resistance and impaired insulin secretion, and curcumin—a polyphenolic compound derived from Curcuma longa—has shown potential anti-inflammatory and antioxidant effects. This randomized, double-blind, placebo-controlled trial evaluated the effects of 1500 mg/day curcumin supplementation for 12 months in 114 adults with T2DM, with assessments including fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), insulin resistance (HOMA-IR), inflammatory cytokines (IL-6, IL-1β, TNF-α), high-sensitivity C-reactive protein (hs-CRP), neutrophil-to-lymphocyte ratio (NLR), antioxidant markers (SOD, GPx, TAS), and malondialdehyde (MDA). Curcumin supplementation was associated with significant reductions in pro-inflammatory cytokines (p < 0.001), hs-CRP and NLR (p < 0.05), and with improved antioxidant status as shown by increased TAS, SOD, and GPx together with reduced MDA levels (p < 0.001). Additionally, improvements in metabolic parameters were observed, including lower FPG (112.0 mg/dL vs. 134.5 mg/dL; p < 0.001), HbA1c (6.10% vs. 6.40%; p < 0.05), and HOMA-IR (4.88 vs. 6.71; p < 0.001). Overall, the findings suggest that long-term curcumin supplementation may contribute to improved inflammatory, antioxidant, and glycemic profiles in obese individuals with T2DM; however, further multi-center studies are needed to confirm these observations and clarify their clinical relevance.