Background

Thousands of studies have been published based on animal and human studies evaluating garlic's effects and safety.

Objective

We reviewed the available literature investigating the effects of garlic supplements on hypertension, hypercholesterolemia, C-reactive protein (CRP), pulse wave velocity (PWV), and coronary artery calcium (CAC), as well as available data on side effects.

Methods

We searched PubMed for all human studies using medical subject heading words through 30 May 2013 and assessed relevant review articles and original studies. Only double-blind, randomized, controlled trials and meta-analyses of double-blind, randomized, controlled trials were included. The review of articles and data extraction were performed by 2 independent authors, with any disagreements resolved by consensus.

Results

Garlic supplementation reduced blood pressure by 7-16 mm Hg (systolic) and 5-9 mm Hg (diastolic) (4 meta-analyses and 2 original studies). It reduced total cholesterol by 7.4-29.8 mg/dL (8 meta-analyses). The most consistent benefits were shown in studies that used aged garlic extract (AGE). A few small studies that used AGE also showed favorable effects on CAC, CRP, and PWV. Although garlic is generally safe, rare adverse reactions have been documented with limited causality established.

Conclusion

We conclude that garlic supplementation has the potential for cardiovascular protection based on risk factor reduction (hypertension and total cholesterol) and surrogate markers (CRP, PWV, and CAC) of atherosclerosis. Larger studies are warranted to evaluate these effects further.

Objectives

The aim of this study was to assess the odds of initiation or continuation of pharmacological and lifestyle preventive therapies in patients with nonzero versus zero coronary artery calcium (CAC) score detected on cardiac computed tomography.

Background

Detection of calcified coronary plaque could serve as a motivational tool for physicians and patients to intensify preventive therapies.

Methods

We searched PubMed, EMBASE (Excerpta Medica database), Web of Science, Cochrane CENTRAL (Cochrane central register of controlled trials), ClinicalTrials.gov, and the International Clinical Trials Registry Platform for studies evaluating the association of CAC scores with downstream pharmacological or lifestyle interventions for prevention of cardiovascular disease. Pooled odds ratios (ORs) of downstream interventions were obtained using the DerSimonian and Laird random effects model.

Results

After a review of 6,256 citations and 54 full-text papers, 6 studies (11,256 participants, mean follow-up time: 1.6 to 6.0 years) were included. Pooled estimates of the odds of aspirin initiation (OR: 2.6; 95% confidence interval [CI]: 1.8 to 3.8), lipid-lowering medication initiation (OR: 2.9; 95% CI: 1.9 to 4.4), blood pressure-lowering medication initiation (OR: 1.9; 95% CI: 1.6 to 2.3), lipid-lowering medication continuation (OR: 2.3; 95% CI: 1.6 to 3.3), increase in exercise (OR: 1.8; 95% CI: 1.4 to 2.4), and dietary change (OR: 1.9; 95% CI: 1.5 to 2.5) were higher in individuals with nonzero CAC versus zero CAC scores, but not for aspirin or blood pressure-lowering medication continuation. When assessed within individual studies, these findings remained significant after adjustment for baseline patient characteristics and cardiovascular risk factors.

Conclusions

This systematic review and meta-analysis suggests that nonzero CAC score, identifying calcified coronary plaque, significantly increases the likelihood of initiation or continuation of pharmacological and lifestyle therapies for the prevention of cardiovascular disease.