Effects of Garlic Supplementation on Cardiovascular Risk Factors in Adults: A Comprehensive Updated Systematic Review and Meta-Analysis of Randomized Controlled Trials.

CONTEXT

Garlic is a well-known ingredient in cooking and has a long history in traditional Asian medicine. Recently, there has been increased interest in its possible protective benefits against cardiovascular diseases (CVDs). While many studies have examined garlic's impact on CVD risk factors, the results have varied. New clinical trials have also been conducted that may provide more definitive insights.

OBJECTIVE

We performed a comprehensive updated meta-analysis to assess the validity of earlier research on garlic's role in managing CVD.

DATA SOURCES

A systematic search was conducted across PubMed, Scopus, and Web of Knowledge from their inception until June 2024, utilizing pertinent keywords.

DATA EXTRACTION

This review encompassed all randomized controlled trials (RCTs) that examined the impact of garlic intake on CVD risk factors in adults. A meta-analysis was executed employing random-effects models, and subgroup analyses were carried out to investigate differences based on dosage, duration, intervention types, health status, and initial risk profiles.

DATA ANALYSIS

Ultimately, 108 trials involving 7137 participants were incorporated into this meta-analysis. Consumption of garlic resulted in a significant improvement in serum levels of triglycerides (weighted mean difference [WMD]: -5.82, 95% CI: -8.16 to -3.49 mg/dL), total cholesterol (WMD: -10.21, 95% CI: -13.69 to -6.74 mg/dL), low-density lipoprotein cholesterol [WMD: -5.90, 95% CI: -10.51 to -1.29 mg/dL], HDL cholesterol (WMD: 2.18, 95% CI: 1.49 to 2.87 mg/dL), fasting blood glucose (WMD: -2.77, 95% CI: -5.25 to -0.28 mg/dL), insulin (WMD: -1.74, 95% CI: -2.26 to -1.22 mU/L), homeostatic model assessment for insulin resistance (WMD: -0.37, 95% CI: -0.59 to -0.15), systolic blood pressure (WMD: -3.71, 95% CI: -5.07 to -2.36 mmHg), diastolic blood pressure (WMD: -1.97, 95% CI: -2.86 to -1.08 mmHg], aspartate aminotransferase (WMD: -2.85, 95% CI: -4.95 to -0.74 IU/L], C-reactive protein (WMD: -1.6, 95% CI: -2.38 to -0.82 mg/L), tumor necrosis factor-α (WMD: -3.94, 95% CI: -5.17 to -2.72 Pg/mL), total antioxidant capacity (WMD: 0.46, 95% CI: 0.15 to 0.76 mmol/L), and malondialdehyde [WMD: -1.03, 95% CI: -1.38 to -0.68 nmol/mL]. Conversely, garlic did not influence apolipoprotein A-1, apolipoprotein B, alanine aminotransferase, interleukin-6, body mass index, weight, or adiponectin (all P ≥ .05).

CONCLUSION

This meta-analysis demonstrates that garlic intake significantly improves key cardiovascular risk markers, including lipid profiles, glycemic indices, blood pressure, oxidative stress, and inflammatory biomarkers, particularly in adults with unfavorable baseline risk factors. These findings suggest that garlic may enhance cardiovascular health in high-risk populations. Further research involving larger sample sizes, extended follow-up periods, and enhanced methodological rigor is essential to draw definitive conclusions.