Effects of Garlic on Glucose Parameters and Lipid Profile: A Systematic Review and Meta-Analysis on Randomized Controlled Trials

🌈 Abstract

The article investigates the effects of garlic on blood glucose levels and lipid parameters in humans through a systematic review and meta-analysis. The key findings are:

• Garlic intervention was effective in controlling fasting blood glucose (FBG), glycosylated hemoglobin (HbA1c), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C), and also increased high-density lipoprotein cholesterol (HDL-C) levels.
• Garlic intervention did not have a significant impact on triglyceride (TG) levels.
• Subgroup analyses showed that the beneficial effects of garlic were more pronounced in trials with longer durations, in participants with type 2 diabetes mellitus, and with certain types of garlic interventions.

🙋 Q&A

[01] Effect of Garlic on Indicators Related to Glucose Metabolism

1. Questions related to the content of the section?

• What was the impact of garlic intervention on fasting blood glucose (FBG) levels?
• What was the impact of garlic intervention on glycosylated hemoglobin (HbA1c) levels?

Answers:

• The garlic intervention demonstrated a significant lowering effect on FBG levels (mean difference = -7.01; 95% CI: -8.53, -5.49, p < 0.001).
• The garlic intervention also had a noteworthy lowering effect on HbA1c levels (mean difference = -0.66; 95% CI: -0.76, -0.55, p < 0.001).

[02] Impact of Garlic on Lipid Profile

1. Questions related to the content of the section?

• What was the impact of garlic intervention on total cholesterol (TC) levels?
• What was the impact of garlic intervention on high-density lipoprotein cholesterol (HDL-C) levels?
• What was the impact of garlic intervention on low-density lipoprotein cholesterol (LDL-C) levels?
• What was the impact of garlic intervention on triglyceride (TG) levels?

Answers:

• The garlic intervention resulted in a significant decrease in TC levels (mean difference = -14.17; 95% CI: -19.31, -9.03, p < 0.001).
• The garlic intervention led to a significant increase in HDL-C levels (mean difference = 2.06; 95% CI: 1.54, 2.59, p < 0.001).
• The garlic intervention caused a substantial reduction in LDL-C concentrations (mean difference = -8.20; 95% CI: -15.58, -0.81, p = 0.03).
• The garlic intervention did not have a statistically significant impact on TG levels (mean difference = -4.88; 95% CI: -11.1, 1.35, p = 0.125).

[03] Subgroup Analysis

1. Questions related to the content of the section?

• How did the effects of garlic on FBG, TC, and LDL-C differ based on the type of garlic intervention, participant population, and duration of the study?

Answers:

• For FBG:
  • The FBG lowering effect was more pronounced in trials with longer durations (>8 weeks) and in participants with type 2 diabetes mellitus.
  • The FBG lowering effect was also more significant in trials using "Other" types of garlic interventions (not aged garlic extract).
• For TC:
  • The TC lowering effect was more pronounced in trials with longer durations (>8 weeks) and in participants with type 2 diabetes mellitus.
  • The TC lowering effect was also more significant in trials using "Other" types of garlic interventions.
• For LDL-C:
  • The LDL-C lowering effect was more significant in trials with longer durations (>8 weeks) and in participants with type 2 diabetes mellitus.

[04] Publication Bias and Sensitivity Analysis

1. Questions related to the content of the section?

• Was there any evidence of publication bias in the studies included in the meta-analysis?
• How did the sensitivity analysis assess the stability of the results?

Answers:

• The funnel plot and Egger's test indicated potential publication bias for TC and LDL-C, but not for the other outcomes.
• The trim and fill analysis showed that the publication bias had little effect on the stability of the TC and LDL-C results.
• The sensitivity analysis, which systematically excluded one study at a time, revealed that no single trial significantly affected the overall effect sizes of FBG, HbA1c, TC, LDL-C, HDL-C, and TG.