Effect of a garlic oil preparation on serum lipoproteins and cholesterol metabolism: a randomized controlled trial.
BACKGROUND
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.


METHODS
Double-blind, randomized, placebo-controlled trial.


METHODS
Outpatient lipid clinic.


METHODS
We investigated 25 patients (mean age, 58 years) with moderate hypercholesterolemia.


METHODS
Steam-distilled garlic oil preparation (5 mg twice a day) vs placebo each for 12 weeks with wash-out periods of 4 weeks.


METHODS
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; triglycerides, 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%0], 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] microg/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.
Berthold
H K
HK
Department of Clinical Pharmacology, University of Bonn, Germany. berthold@uni-bonn.de
Sudhop
T
T
von Bergmann
K
K
D000328:Adult; D001835:Body Weight; D002784:Cholesterol / Q000378:metabolism*; D004311:Double-Blind Method; D005737:Garlic / Q000627:therapeutic use*; D006801:Humans; D006937:Hypercholesterolemia / Q000097:blood / Q000188:drug therapy*; D008074:Lipoproteins / Q000097:blood*; D008875:Middle Aged; D008517:Phytotherapy; D010938:Plant Oils / Q000494:pharmacology* / Q000627:therapeutic use; D010946:Plants, Medicinal
D008074:Lipoproteins; D010938:Plant Oils; D002784:Cholesterol