A systematic review of randomized controlled trials related to the effects of garlic supplementation on platelet aggregation.

The increment of platelet aggregation factors has been considered a key phenomenon in atherosclerosis. Studies have shown that garlic (Allium sativum) is associated with a reduction in platelet aggregation and thrombosis. Hence, the present systematic review was conducted to evaluate the effect of garlic on platelet aggregation. All randomized controlled trials (RCTs) with keywords related to garlic and platelet aggregation were thoroughly searched in electronic databases including PubMed, Scopus, ISI Web of Science, and Google Scholar up to January 2021. Moreover, the references of all related articles were screened to discover more relevant studies. The quality of each study was reported based on Cochrane Collaboration's tool. In total, 12 studies met the inclusion criteria from 18,235 identified articles (including 595 participants). Most of the studies assessed platelet aggregation in response to different inducers. Of the 12 clinical trials, six studies depicted the beneficial effect of garlic on reducing platelet aggregation. The summary of the quality assessment indicated that most of the studies had high-quality scores. Regarding the small number of RCTs and heterogeneity between studies, it is impossible to make a proper conclusion about the impacts of garlic on platelet aggregation. Therefore, further precise trials with a standard design are necessary to validate the anti-thrombotic effect of garlic.

Effects of garlic supplementation on liver enzymes: A systematic review and meta-analysis of randomized controlled trials.

Current evidence on the beneficial effects of garlic on liver enzymes is contradictory. Therefore, the aim of this systematic review and meta-analysis is to evaluate the effect of garlic supplementation on human liver enzymes, such as Alanine Transaminase (ALT/SGPT) and Aspartate Transaminase (AST/SGOT). To collect the required data, PubMed, Scopus, ISI Web of Science, and Google scholar databases were systematically searched from inception to June 2019. A meta-analysis was conducted using the random-effects model to evaluate the effects of garlic supplementation on ALT and AST levels. The Cochran's Q-test and inconsistency index were also used to evaluate heterogeneity among the studies. Among a total of 15,514 identified articles, six studies (containing 301 participants) met the inclusion criteria. Results of the meta-analysis showed that garlic supplementation significantly decreased AST level (Hedges' g = -0.36, 95% confidence interval [CI]: -0.72, -0.004, p = .047); whereas, it had no significant effect on ALT level (Hedges' g = -0.22, 95% CI: -0.64, 0.20, p = .310). Results showed that garlic supplementation reduced AST levels significantly; however, had no significant effect on ALT levels. Further studies are still needed to confirm the results.