Effect of garlic powder on C-reactive protein and plasma lipids in overweight and smoking subjects.

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.

METHODS

This was a double-blind, randomized, placebo-controlled trial in 90 overweight [body mass index (in kg/m2) > 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 alpha (TNF-alpha; 41.9%; 19.0%, 58.3%) and increased the ratio of ex vivo whole blood lipopolysaccharide-stimulated to nonstimulated TNF-alpha concentrations (109.7%; 37.9%, 218.9%).

CONCLUSIONS

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.