Vitamin C may have similar beneficial effects to Gemfibrozil on serum high‑density lipoprotein‑cholesterol in type 2 diabetic patients

Type 2 diabetes mellitus (DM‑T2) is commonly associated with increased triglycerides (TG), low‑density lipoprotein cholesterol (LDL‑C) and low high‑density lipoprotein cholesterol (HDL‑C) levels. Fibrates like gemfibrozil are frequently used in diabetic patients to decrease TG and increase HDL‑C levels. We compared the efficacy of Vitamin C, an antioxidant vitamin, with gemfibrozil on serum HDL‑C in diabetic patients.

Type 2 diabetic patients, referred to our out‑patient clinic were randomly divided into three groups. After 1 month of lifestyle and diet modifications, groupsA, B, and C were prescribed 1000 mg Vitamin C, 600 mg gemfibrozil and combination of both, respectively. Before the study initiation and after 6th week of drug prescription, the blood samples were taken and analyzed for total cholesterol (Total‑C), HDL‑C, TG, fasting blood sugar (FBS), and hemoglobin A1c (HbA1c) levels.

Sixty‑seven patients entered, and 50 patients (18 male, 32 female) finished the study. Overall, serum HDL‑C increased significantly from 39.8 to 45.2 mg/dL in the participants (P = 0.001). HDL‑C increased 6.3, 4.4 and 5.0 mg/dL in groups A, B and C, respectively (related significances were 0.017, 0.022 and 0.033, respectively). Significant decrease of serum TG and Total‑C occurred in gemfibrozil and combination groups, but not in Vitamin C group. Changes in serum HDL‑C between three groups were not significant (P = 0.963). We found a significant decrease in TG and Total‑C in the groups B and C (P < 0.05), but no significant changes of TG, Total‑C, LDL‑C, FBS and HbA1c in group A (P > 0.05).

The results demonstrated that Vitamin C may have beneficial effects on HDL‑C in diabetic patients without significant effects on plasma glucose or other lipid parameters; however, its role for the treatment of low HDL‑C patients should be evaluated in larger studies.