Effects of native Lactobacillus rhamnosus, Lactobacillus fermentum, and Lactobacillus plantarum on serum level of omentin-1, glycemic markers, and lipid profile in obese adults: A triple-blind clinical trial

Background: Obesity is a multifactorial disorder strongly associated with metabolic dysfunction and chronic inflammation. Emerging evidence suggests that modulation of the gut microbiota through probiotic supplementation may improve metabolic outcomes. This study investigated the effects of three native Lactobacillus strains on serum omentin-1 levels, glycemic indices, and lipid profiles in obese adults. Methods: In this 8-week, triple-blind, randomized, placebo-controlled clinical trial, 100 obese adults (BMI 30–40 kg/m²) were assigned to four groups receiving daily sachets containing Lactobacillus fermentum NIMBB014, Lactobacillus rhamnosus NIMBB006, Lactobacillus plantarum (2 × 10⁹ CFU), or placebo. Serum omentin-1, anthropometric, glycemic (FBS, HbA1c, insulin, HOMA-IR, QUICKI, serum α-amylase), and lipid (TC, TG, HDL, LDL, VLDL) parameters were assessed at baseline and after 8 weeks. Data were analyzed using the paired t-tests and ANCOVA, adjusting for age, sex, baseline values, and BMI. Results: After 8 weeks, no significant between-group differences were observed in omentin-1 or glycemic indices. However, within-group analyses indicated significant reductions in insulin and QUICKI in both the L. fermentum and L. plantarum groups (P < 0.05). L. plantarum supplementation resulted in a significant decrease in total cholesterol (P = 0.008) and an increase in HDL (P = 0.046) compared with placebo, along with significant within-group reductions in TG and VLDL (P < 0.05). No adverse effects were reported. Conclusion: These findings suggest strain-specific probiotic benefits in obesity management, warranting longer interventions and larger trials to confirm metabolic effects.