Garlic’s Effects on Intestinal Transit Time and Cardiometabolic Indices in Patients with the Metabolic Syndrome

by | Jul 5, 2023 | 2023, Blood Lipids, Cardiovascular Health, Garlic, Metabolic Syndrome

Written by Harold Oster, MD. Results show that garlic supplementation may improve intestinal transit time and cardiometabolic indices in patients with metabolic syndrome. 

Metabolic syndrome, which is increasing in prevalence worldwide, is a cluster of risk factors for cardiovascular disease and diabetes. Patients have abdominal obesity, hypertension, elevated glucose, and dyslipidemia1. Metabolic syndrome is associated with increased cardiovascular disease and overall mortality2. Altered gut microbiota, also known as dysbiosis, may cause constipation and diarrhea through its effect on intestinal transit time. Dysbiosis may also be associated with metabolic syndrome3,4. Several laboratory indices have been shown to correlate with a patient’s risk of cardiovascular disease. These include the lipid accumulation product (LAP), which incorporates waist circumference and triglycerides5; the cardiometabolic index (CMI), which uses triglycerides, HDL, and the waist circumference/height ratio6; the atherogenic index of plasma (AIP), the log of triglycerides divided by HDL7; and the Castelli risk index (CRI) 1, a ratio of total cholesterol and HDL, and CRI 2, a ratio of LDL and HDL8. Garlic, through its anti-inflammatory, antioxidant, and lipid-lowering properties, has beneficial effects on cardiovascular and metabolic disorders9.

Abbas Sangouni et al. studied the potential beneficial effect of garlic on intestinal transit time, LAP, and several cardiometabolic indices in patients with metabolic syndrome. Ninety participants with metabolic syndrome were randomized to receive four 400mg tablets of garlic powder containing 1.5mg of allicin, one of garlic’s major bioactive compounds, or an identical placebo daily for three months. Participants were evaluated for total energy intake and consumption of allicin-rich foods at baseline, week 6, and week 12. At the same time intervals, their height, weight, and waist circumference were measured, and blood was tested for the components of the cardiometabolic indices. Intestinal transit time was assessed by the Bristol stool scale, a marker for bowel health10.

The authors noted the following:

  • Baseline characteristics were similar in the garlic and placebo groups, except CRI-2 was higher in the garlic group.
  • Energy intake decreased significantly in the treatment group over the course of the study.
  • Intake of allicin-rich foods was similar in the two groups.
  • Intestinal transit time improved in the garlic group.
  • The lipid accumulation product and cardiometabolic indices improved significantly in the treatment group. Adjustment for the decrease in energy intake of the garlic group did not affect the results.

Results of the study suggest that garlic powder supplementation improves intestinal transit time, lipid accumulation product, and several cardiometabolic indices in patients with metabolic syndrome. Limitations of the study include the lack of assessment of the gut microbiota and the lack of a more structured evaluation of dietary factors that may have affected intestinal transit time.

Source: Sangouni, Abbas Ali, Mohammad Alizadeh, Atena Jamalzehi, Mahdieh Hosseinzadeh, and Karim Parastouei. “Garlic supplementation improves intestinal transit time, lipid accumulation product and cardiometabolic indices in subjects with metabolic syndrome: A randomized controlled trial.” Phytotherapy Research 37, no. 6 (2023): 2305-2314.

© 2023 John Wiley & Sons Ltd.

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Posted July 5, 2023.

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:

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  2. Guembe MJ, Fernandez-Lazaro CI, Sayon-Orea C, Toledo E, Moreno-Iribas C. Risk for cardiovascular disease associated with metabolic syndrome and its components: a 13-year prospective study in the RIVANA cohort. Cardiovasc Diabetol. Nov 22 2020;19(1):195. doi:10.1186/s12933-020-01166-6
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