| Abstract: | Context.— Garlic-containing drugs have been used in the treatment of hypercholesterolemia even though their efficacy is not generally established. Little is known about the mechanisms of action of the possible effects on cholesterol in humans. Objective.— To estimate the hypocholesterolemic effect of garlic oil and to investigate the possible mechanism of action. Design.— Double-blind, randomized, placebo-controlled trial. Setting.— Outpatient lipid clinic. Patients.— We investigated 25 patients (mean age, 58 years) with moderate hypercholesterolemia. Intervention.— Steam-distilled garlic oil preparation (5 mg twice a day) vs placebo each for 12 weeks with wash-out periods of 4 weeks. Main Outcome Measures.— Serum lipoprotein concentrations, cholesterol absorption, and cholesterol synthesis. Results.— Baseline lipoprotein profiles were (mean SD]): total cholesterol, 7.53 (0.75) mmol/L (291 29] mg/dL); low-density lipoprotein cholesterol (LDL-C), 5.35 (0.78) mmol/L (207 30] mg/dL); high-density lipoprotein cholesterol (HDL-C), 1.50 (0.41) mmol/L (58 16] mg/dL); and triglycerides, 1.45 (0.73) mmol/L (127 64] mg/dL). Lipoprotein levels were virtually unchanged at the end of both treatment periods (mean difference 95% confidence interval]): total cholesterol, 0.085 (-0.201 to 0.372) mmol/L (3.3 -7.8 to 14.4] mg/dL), P=.54; LDL-C, 0.001 (-0.242 to 0.245) mmol/L (0.04 -9.4 to 9.5] mg/dL), P=.99; HDL-C, 0.050 (-0.028 to 0.128) mmol/L (1.9 -1.1 to 4.9] mg/dL), P=.20; triclycerides, 0.047 (-0.229 to 0.135) mmol/L (4.2 -20.3 to 12.0]) mg/dL, P=.60. Cholesterol absorption (37.5% 10.5%] vs 38.3% 10.7%], P=.58), cholesterol synthesis (12.7 6.5] vs 13.4 6.6] mg/kg of body weight per day, P=.64), mevalonic acid excretion (192 66] vs 187 66] µg/d, P=.78), and changes in the ratio of lathosterol to cholesterol in serum (4.4% 24.3%] vs 10.6% 21.1%], P=.62) were not different in garlic and placebo treatment. Conclusions.— The commercial garlic oil preparation investigated had no influence on serum lipoproteins, cholesterol absorption, or cholesterol synthesis. Garlic therapy for treatment of hypercholesterolemia cannot be recommended on the basis of this study. |
