Effect of Fenugreek Seed Supplementation on Fasting and Postprandial Glucose in Type 2 Diabetes Mellitus: A Single-Group Pre–Post Study

Abstract

Background: Type 2 diabetes mellitus (T2DM) is a growing public-health challenge in India, and there is sustained interest in low-cost dietary adjuncts to conventional pharmacotherapy. Fenugreek (Trigonella foenum-graecum), known locally as methi or vendhayam, is a culinary staple in South India whose soluble fibre and bioactive constituents have plausible glucose-lowering activity. Objective: To estimate the pre–post change in fasting blood glucose (FBG), postprandial blood glucose (PPBG) and glycated haemoglobin (HbA1c) following 12 weeks of adjunctive fenugreek seed supplementation in adults with T2DM. Methods: In this single-group (single-arm) pre–post interventional study conducted at a tertiary care teaching hospital in South India, 60 adults (aged 35–70 years) with established T2DM on stable oral antidiabetic therapy received fenugreek seed powder 10 g/day in two divided doses for 12 weeks as an adjunct to their existing regimen. FBG, PPBG, HbA1c, weight and body mass index (BMI) were measured before and after the intervention. Paired t-tests, 95% confidence intervals (CI) and Cohen's dz effect sizes were computed. Results: All 60 participants completed the study (mean adherence 90.6%). FBG fell from 160.42 (SD 25.59) to 135.87 (SD 27.42) mg/dL (mean change −24.55 mg/dL; 95% CI −26.65 to −22.46; p<0.001; dz=−3.03). PPBG fell from 234.33 (SD 34.61) to 197.25 (SD 35.28) mg/dL (mean change −37.08 mg/dL; 95% CI −40.17 to −33.99; p<0.001; dz=−3.10). HbA1c fell from 8.12 (SD 0.73) to 7.54 (SD 0.76) % (mean change −0.59 percentage points; 95% CI −0.63 to −0.54; p<0.001; dz=−3.32). Weight and BMI decreased modestly (−1.40 kg; −0.51 kg/m²). Only mild adverse effects occurred (8/60, 13.3%). Conclusion: Twelve weeks of adjunctive fenugreek 10 g/day was associated with clinically and statistically significant reductions in FBG, PPBG and HbA1c, with good tolerability, in this South Indian sample. Because the single-arm design has no control group, these associations cannot be attributed to fenugreek alone.