Eight Weeks of Vitamin C Supplementation Restores the Lost Correlation between Serum Leptin and C-reactive Protein (CRP) in Patients with Type 2 Diabetes; A Randomized, Double-blind, Parallel-group, Placebo-controlled Clinical Trial

Abstract

Objective: Inflammation is a well-described factor in the pathophysiology of type 2 diabetes mellitus (DM), which has been a suspect in the alteration of correlations between CRP and leptin in patients with type 2 DM. Aim: This study aimed to show the effect of vitamin C as an antioxidant on the correlation of the serum levels of C-reactive protein (CRP) and leptin in patients with type 2 DM. Methods: We recruited 70 patients with longstanding T2DM and randomly assigned them into two groups; one received 500 mg/day of vitamin C, and the other received a placebo for eight weeks. Both groups were matched regarding baseline characteristics such as age, gender, weight, and diabetic medications. Results: Out of 70 individuals, 57 participants were left in the study. After eight weeks of follow-up, leptin level was significantly increased in the Vitamin C group (MD = 3.48 change = 24%, p-value = 0.001) but did not change in the placebo group. Other markers such as Fasting plasma glucose, HbA1c, Creatinine, uric acid, Urea, cholesterol, HDL, LDL, TG, AST, ALT, insulin, and CRP did not significantly change in both groups (p value > 0.05). The significant changes in the leptin level among the vitamin C group also remained after controlling for age, BMI, Blood pressure (BP), Triglyceride (TG), and cholesterol. Also, the correlation between serum CRP and leptin became significant in the vitamin C group after eight weeks of follow-up but not in the placebo group. (rs = 0.730, p < 0.001 vs. rs = 0.286, p-value = 0.266 in placebo group). Conclusion: This study shows vitamin C can restore CRP-leptin correlation in patients with type 2 diabetes and increase serum leptin levels. More studies are needed to clarify the mechanism of this restoration. Clinical Trial Registration Number: IRCT20160811029306N1.