China: Results from a meta-analysis of 10 randomized controlled trials comprising 999 participants suggested that garlic is a potentially beneficial medicinal food product for metabolic syndrome (MetS).
The study, published in BMC Complementary Medicine and Therapies, revealed that garlic supplementation partially modulated the blood pressure (systolic blood pressure), serum lipid profile (triglyceride, TGL, high-density lipoprotein), and anthropometric parameters (waist circumference, body mass index) of MetS.

Metabolic syndrome is a condition of metabolic disorder in which dyslipidemia, central obesity, hypertension, and insulin resistance exist as a cluster. Currently, there is no availability of comprehensive treatment and management plan available for MetS, and modification of dietary habits is a simple, feasible, and efficient intervention.
Garlic (Allium sativum) is the underground bulb of the Allium genus that has been used for consumption for thousands of years. In recent years, many clinical trials have emerged in recent years of garlic supplementation on components of MetS, but there is no consensus on the effect. Therefore, Qingqiao Song, China Academy of Chinese Medical Sciences, Beijing, China, and colleagues aimed to systematically evaluate the effect of garlic supplementation on components of MetS in a meta-analysis.
For this purpose, the researchers searched online databases, and clinical trial online sites from inception to November 1, 2022. Participants > 18 years and eligible for the clinical diagnosis of MetS or those with metabolic disorders and garlic was the only intervention were included. The outcomes of the study included fasting blood glucose, blood pressure, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, total cholesterol, triglycerides, body mass index, and waist circumference.
Based on six covariates (the mean age, total sample size, the mean dose, the oral form of garlic, the duration of intervention, and the dietary intervention) meta-regression and subgroup analyses were conducted. Results from 19 randomized controlled trials were included engaging 999 participants.
The researchers reported the following findings:
Compared to placebo, garlic significantly reduced TG [SMD = -0.66], TC [SMD = -0.43], LDL [SMD = -0.44], DBP [SMD = -1.33], BMI [SMD = -1.10], and WC [SMD = -0.78].
Meta-regression showed age and sample size are potential effect modifiers.
"According to the results of the meta-analysis, the modulatory effect of garlic on some components of metabolic syndrome is evident," the researchers wrote. "However, based on the current evidence, we cannot draw a robust conclusion on the beneficial extent of garlic supplementation on MetS, and there is a need for further large-scale RCTs to support this conclusion."
Reference:
Fu, Z., Lv, J., Gao, X. et al. Effects of garlic supplementation on components of metabolic syndrome: a systematic review, meta-analysis, and meta-regression of randomized controlled trials. BMC Complement Med Ther 23, 260 (2023). https://doi.org/10.1186/s12906-023-04038-0