Antiatherosclerotic effects of licorice extract supplementation on hypercholesterolemic patients: decreased CIMT, reduced plasma lipid levels, and decreased blood pressure

BACKGROUND Ethanolic extract of licorice root has been shown to reduce low-density lipoprotein (LDL) oxidation in atherosclerotic mice and in both hypercholesterolemic and normal lipidemic humans. OBJECTIVE This study examined the effect of licorice-root extract on carotid intima-media thickness (CIMT) in individuals with hypercholesterolemia. DESIGN Individuals with hypercholesterolemia (total cholesterol ≥6.18 mmol/L [240 mg/dL]) and without significant stenosis were randomly allocated to two groups: an experimental group that consumed 0.2 g/day of ethanolic extract of licorice root for 12 months, and a control group that received a placebo. RESULTS Of 110 eligible participants, 94 (41-80 years old) completed the study. A significant CIMT decrease from 0.92±0.25 mm to 0.84±0.21 mm was observed in the experimental group compared with an increase from 0.85±0.17 mm to 0.88±0.19 mm in the control group. Mean plasma total cholesterol levels and LDL cholesterol decreased, at the range baseline to 1 year, from 284±32 mg/dl to 262±25 mg/dl and from 183±8.5 mg/dl to 174±9.1 mg/dl, respectively, for the experimental group (p<0.001) and from 291±35 to 289±31 mg/dl and from 177.6±10.7 to 179.3±9.6 (p=0.08), respectively, for the control group. Mean high-density lipoprotein (HDL) did not change significantly in either group. In the experimental group, systolic blood pressure decreased from 138±12 mmHg to 125±13 mmHg after 1 year (p=0.01) and increased from 136±15 mmHg to 137±13 mmHg in the control group. Diastolic blood pressure decreased from 92±9 mmHg to 84±10 mmHg (p=0.01) in the experimental group and increased from 89±11 mmHg to 90±8 mmHg in the control group. CONCLUSION Following 1 year of licorice consumption, mean CIMT, total cholesterol, LDL levels, and blood pressure were decreased. This suggests that licorice may attenuate the development of atherosclerosis and of related cardiovascular diseases.