Effect of garlic on serum lipids: an updated meta-analysis

Abstract

Background: Epidemiologic studies suggest that garlic may have beneficial effects on risk factors associated with cardiovascular disease (CVD).However, these findings are not unambiguously supported by randomized placebo-controlled clinical trials.Objective: We sought to investigate the effects of a chemically well-characterized garlic preparation on biomarkers for inflammation, endothelial function, and lipid metabolism in subjects with risk factors for CVD.Design: This was a double-blind, randomized, placebo-controlled trial in 90 overweight [body mass index (in kg/m 2 ) 24.5] subjects aged 40 -75 y who smoked 10 cigarettes/d.The subjects were randomly assigned to 3 parallel treatment groups: garlic powder (2.1 g/d), atorvastatin (40 mg/d), or placebo.Duplicate measurements were performed at baseline and after 1 and 3 mo of treatment.Treatments were compared with analysis of covariance with baseline as the covariate, and differences between the treatments were reported as mean percentage difference and corresponding 97.5% CI.Results: None of the variables showed significant differences between the garlic-treated and the placebo groups.In contrast, compared with the placebo group, atorvastatin treatment resulted in significantly lower plasma concentrations of C-reactive protein (20.2%; 1.7%, 35.3%), total cholesterol (37.2%; 33.1%, 41.1%), LDL cholesterol (52.7%; 47.9%, 57.1%), triacylglycerols (31.9%; 20.8%, 41.5%), and tumor necrosis factor ␣ (TNF-␣; 41.9%; 19.0%, 58.3%) and increased the ratio of ex vivo whole blood lipopolysaccharidestimulated to nonstimulated TNF-␣ concentrations (109.7%;37.9%, 218.9%). Conclusion:We conclude that a chemically well-characterized garlic preparation has no significant effect on inflammatory biomarkers, endothelial function, or lipid profile in normolipidemic subjects with risk factors for CVD.