Effects of L-carnitine supplementation on lipid profiles in patients with coronary artery disease

Background: L-carnitine (LC) plays an important physiologic role in lipid metabolism. To date, no clinical study has been performed to examine the effect of LC supplementation on the lipid status of coronary artery disease (CAD) patients. The aim of this study was to investigate the lipid lowering effects of LC supplementation (1000 mg/d) in CAD patients. Methods: CAD patients were identified by cardiac catheterization as having at least 50 % stenosis of one major coronary artery. Forty-seven subjects were recruited and randomly assigned to the placebo (n = 24) and to the LC (n = 23) groups. The intervention was administered for 12 weeks. The levels of LC, lipid profiles, and antioxidant enzyme activity (superoxide dismutase, SOD) were measured. Results: The subjects in the LC group had significantly higher SOD activity (20.7 ± 4.2 versus 13.1 ± 2.9 U/mg of protein, P < 0.01), high density lipoprotein-cholesterol (1.34 ± 0.42 vs. 1.16 ± 0.24 mmol/L, HDL-C, P = 0.03), and apolipoprotein-A1 (Apo-A1, 1.24 ± 0.18 vs. 1.12 ± 0.13 g/L, P = 0.02) than those in the placebo group at week 12. Triglyceride (TG) level was slightly significantly reduced (1.40 ± 0.74 vs. 1.35 ± 0.62 mmol/L, P = 0.06) and the level of LC was negatively correlated with TG and apolipoprotein-B (Apo-B), and positively correlated with HDL-C and Apo-A1 after LC supplementation. Additionally, SOD activity was significantly negatively correlated with lipid profiles (total cholesterol, TG, and Apo-B) after supplementation. Conclusion: LC supplementation at a dose of 1000 mg/d showed significantly increased in HDL-C and Apo-A1 levels and a slight decrease in TG levels but no other changes in other lipids in CAD patients, and this lipid-lowering effect may be related to its antioxidant ability. Further studies should be conducted to define an optimal dose of LC for lipid-lowering in patients with CAD.