Written by Harold Oster, MD. Results suggest that garlic supplementation improves fasting blood glucose, hemoglobin A1C, and lipid levels.
The prevalence of diabetes is increasing globally, in large part due to the increasing prevalence of obesity. Diabetes is associated with various complications, including heart disease, stroke, and overall mortality1. Hyperlipidemia is also associated with cardiovascular disease, and improving the lipid profile reduces the risk of coronary events and stroke2. Garlic, used as a spice around the world, contains compounds, such as allicin, with anti-inflammatory, antioxidant, and glucose and lipid-reducing properties3.
Xinyu Zhao et al. studied the effects of garlic on blood glucose and lipid levels by conducting a meta-analysis. The authors searched the medical literature for randomized controlled trials examining the effects of garlic supplementation on levels of fasting blood glucose, hemoglobin A1C, total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and triglycerides. The authors compared the changes in the levels of the above tests in participants who consumed garlic supplements and in controls who did not.
The authors noted the following:
- Based on inclusion criteria, 29 studies involving 1,567 total participants were used in the meta-analysis.
- The forms and dosages of garlic supplementation varied across the studies.
- Fasting blood glucose levels in those who consumed garlic fell 7.01 mg/dL more than in the controls.
- HbA1c levels fell 0.66 more in those who consumed garlic.
- The mean total cholesterol level was 14.17 mg/dL lower in the participants who consumed garlic.
- LDL levels fell 8.20 mg/dL more in those who took garlic supplements.
- HDL levels were 2.06 mg/dL higher in participants who consumed garlic.
- Triglyceride levels did not change significantly in those who took garlic supplements.
Results suggest that garlic supplementation reduces glucose and hemoglobin A1C levels and improves the lipid profile. The study’s limitations include inconsistent garlic dosages and possible publication bias in the studies used in the meta-analysis.
Source: Zhao, Xinyu, Tao Cheng, Hui Xia, Yanhong Yang, and Shaokang Wang. “Effects of Garlic on Glucose Parameters and Lipid Profile: A Systematic Review and Meta-Analysis on Randomized Controlled Trials.” Nutrients 16, no. 11 (2024): 1692.
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Harold Oster, MD graduated from medical school in Miami, Florida in 1992 and moved to Minnesota in 2004. After more than 25 years of practicing Internal Medicine, he recently retired. Dr. Oster is especially interested in nutrition, weight management, and disease prevention. Visit his website at haroldoster.com.
References:
- Harding JL, Pavkov ME, Magliano DJ, Shaw JE, Gregg EW. Global trends in diabetes complications: a review of current evidence. Diabetologia. Jan 2019;62(1):3-16. doi:10.1007/s00125-018-4711-2
- Colantonio LD, Bittner V, Reynolds K, et al. Association of Serum Lipids and Coronary Heart Disease in Contemporary Observational Studies. Circulation. Jan 19 2016;133(3):256-64. doi:10.1161/circulationaha.115.011646
- Ansary J, Forbes-Hernández TY, Gil E, et al. Potential Health Benefit of Garlic Based on Human Intervention Studies: A Brief Overview. Antioxidants (Basel, Switzerland). Jul 15 2020;9(7)doi:10.3390/antiox9070619