G. sylvestre Supplementation Increases Insulin Sensitivity in Subjects with Impaired Glucose Tolerance

by | Nov 14, 2022 | Blood Sugar, Botanicals, Diabetes

Written by Taylor Woosley, Staff Writer. Results of this 12-week randomized, double-blind, placebo-controlled clinical trial of 600 mg/day supplementation of G. sylvestre show that, at the end of the intervention, 46.7% of patients obtained normal values in A1C. 

man testing blood sugarA major epidemic of diabetes has occurred, with the worldwide prevalence of the condition rising from 150 million cases in 2000 to an estimated 425 million in 2017, projected to increase to 629 million by 20451. The impaired glucose tolerance (IGT) is considered as a representative prediabetes and emerges before the onset of type 2 diabetes2. IGT is often part of the metabolic syndrome, and is associated with central obesity, hypertension, hypertriglyceridemia, and low HDL3. The natural progression of dysglycemia involves increasing insulin resistance and loss of pancreatic β-cell function4.

Gymnema sylvestre, a medicinal plant, is traditionally used for the treatment of various diseases, including diabetes5. Several constituents of the plant (gymnemic acids, gurmarin and gymnemasaponin V) act together to normalize blood sugar levels by decreasing plasma glucose6. Previous studies of this plant afforded that it has broad biological activities from antidiabetic effect, for example, increasing insulin secretion by the pancreas and regeneration of pancreatic islet cells7.

Martinez et al. conducted a randomized, double-blind, placebo-controlled clinical trial to evaluate the effects of G. sylvestre administration on glycemic control, insulin secretion, and insulin sensitivity in subjects with IGT. Subjects (n=30, aged 30-59 years old) were included in the study if they had a clinical diagnosis of IGT according to the American Diabetes Association (defined as a 2-h postload plasma glucose [2-h PG) concentration between 7.8 and 11.1 mmol/L). Subjects were divided into receiving either 300 mg of oral capsules of G. sylvestre or homologated placebo before breakfast and dinner (total of 600 mg/day) for 12 weeks. All study participants were considered sedentary, non-smokers, with a body mass index (BMI) ranging between 25-39.9 kg/m2 and a stable body weight (BWt).

Subjects underwent assessments at baseline and at completion of study. Weight, height, waist circumference, and blood samples to measure fasting plasma glucose, glycated hemoglobin A1C, triglycerides, total cholesterol, high-density lipoprotein cholesterol, and fasting insulin concentrations were measured. Additionally, a 2-h oral glucose tolerance test (2-h OGTT) was performed by consuming 75 g of a dextrose load, with two blood samples being obtained at 30, 60, 90, and 120 min after glucose administration. The Shapiro-Wilk test was utilized to assess normality, and nonparametric tests were used to compare continuous data. Wilcoxon signed-rank test and Mann-Whitney U test were performed to evaluate intra- and intergroup differences, respectively, and chi-square or Fisher’s exact test was utilized to assess the differences in nominal variables.

Results of the study show a significant reduction in 2-h OGTT (9.1 ± 1.2 vs. 7.8 ± 1.7 mmol/L, p = .003), A1C (5.8 ± 0.3% vs. 5.4 ± 0.4%, p = .025), body weight, BMI, and low-density lipoprotein cholesterol levels in the G. sylvestre group, with an increment in the Matsuda index (1.8 ± 0.8 vs. 2.4 ± 1.2, p = .008). 46.7% of study participants obtained normal values in A1C at the end of the intervention. Study findings show that 12-week supplementation of 600 mg/day of G.sylvestre decreased A1C levels and 2-h OGTT, therefore increasing insulin sensitivity. Study limitations include lack of body composition analysis and the inability to generalize the results to an open population with IGT based on the narrow inclusion criteria of the study.

Source: Gaytán Martínez, Luis A., Luis A. Sánchez-Ruiz, Laura Y. Zuñiga, Manuel González-Ortiz, and Esperanza Martínez-Abundis. “Effect of Gymnema sylvestre administration on glycemic control, insulin secretion, and insulin sensitivity in patients with impaired glucose tolerance.” Journal of medicinal food 24, no. 1 (2021): 28-32.

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Posted November 14, 2022.

Taylor Woosley studied biology at Purdue University before becoming a 2016 graduate of Columbia College Chicago with a major in Writing. She currently resides in Glen Ellyn, IL.

References:

  1. Gong Q, Zhang P, Wang J, et al. Morbidity and mortality after lifestyle intervention for people with impaired glucose tolerance: 30-year results of the Da Qing Diabetes Prevention Outcome Study. The lancet Diabetes & endocrinology. Jun 2019;7(6):452-461. doi:10.1016/s2213-8587(19)30093-2
  2. Tian X, Zhang Y, Li H, et al. Palmatine ameliorates high fat diet induced impaired glucose tolerance. Biol Res. Sep 14 2020;53(1):39. doi:10.1186/s40659-020-00308-0
  3. Osei E, Zandbergen A, Brouwers P, et al. Safety, feasibility and efficacy of metformin and sitagliptin in patients with a TIA or minor ischaemic stroke and impaired glucose tolerance. BMJ Open. Sep 16 2021;11(9):e046113. doi:10.1136/bmjopen-2020-046113
  4. Brannick B, Dagogo-Jack S. Prediabetes and Cardiovascular Disease: Pathophysiology and Interventions for Prevention and Risk Reduction. Endocrinol Metab Clin North Am. Mar 2018;47(1):33-50. doi:10.1016/j.ecl.2017.10.001
  5. Khan F, Sarker MMR, Ming LC, et al. Comprehensive Review on Phytochemicals, Pharmacological and Clinical Potentials of Gymnema sylvestre. Front Pharmacol. 2019;10:1223. doi:10.3389/fphar.2019.01223
  6. Turner S, Diako C, Kruger R, et al. Consuming Gymnema sylvestre Reduces the Desire for High-Sugar Sweet Foods. Nutrients. Apr 10 2020;12(4)doi:10.3390/nu12041046
  7. Liu M, Zhou T, Zhang J, Liao G, Lu R, Yang X. Correction: Liu et al. Identification of C(21) Steroidal Glycosides from Gymnema sylvestre (Retz.) and Evaluation of Their Glucose Uptake Activities. Molecules 2021, 26, 6549. Molecules. Sep 5 2022;27(17)doi:10.3390/molecules27175718