Effect of garlic supplement in the management of type 2 diabetes mellitus (T2DM): a meta-analysis of randomized controlled trials
The present study was designed to systematically evaluate the clinical efficacy and safety of garlic supplement in the management of type 2 diabetes mellitus (T2DM). PubMed, EMBASE, the Cochrane Library, and China National Knowledge Internet (CNKI) were searched for relevant randomized controlled trials (RCTs) by using the terms garlic and T2DM up to April 2017. The quality of included RCTs was assessed by the Cochrane tool of risk of bias, and data of outcomes were pooled by REVMAN 5.3. Clinical factors were handled by meta-regression and subgroup analysis, and risk of publication bias was explored by inverted funnel plots. Nine RCTs involving 768 T2DM patients were included in the meta-analysis, and the dose of daily garlic (allicin) supplement ranged from 0.05g to 1.5g. A significant reduction in the level of fasting blood glucose in 1–2 weeks [SMD = −1.61, 95%CI (−2.89, −0.32)], 3–4 weeks [SMD = −2.87, 95%CI (−4.74, −1.00)], 12 weeks [SMD = −9.57, 95%CI (−12.39, −6.75)], and 24 weeks [SMD = −21.02, 95%CI (−32.47, −9.57)] was achieved in favour of the garlic group rather than the control group. Significantly decreased fructosamine and glycated hemoglobin (both in 12 and 24 weeks) were also found in garlic group. Meanwhile, significantly improved blood liquids of total cholesterol [SMD = −1.93, 95%CI (−2.98, −0.87), 3–4 weeks], high density lipoprotein [SMD = −0.41, 95%CI (−0.83, −0.00), 3–4 weeks] and low density lipoprotein [SMD = −3.47, 95%CI (−5.76, −1.18), 12 weeks] were confirmed after garlic administration. There was no significant difference in complications. Current data confirms that garlic supplement plays positive and sustained roles in blood glucose, total cholesterol, and high/low density lipoprotein regulation in the management of T2DM.
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