Obesity, type 2 diabetes, and the gut microbiome: A case-control investigation of L. acidophilus, L. rhamnosus, and B. bifidum

This case-control study aimed to investigate three bacterial strains reported to have positive effects on obesity and diabetes mellitus in animal studies in treatment-naive patients referred to an obesity clinic in Tehran. Treatment-naive patients with BMI ≥ 30 were enrolled in this study, and healthy individuals without DM and with BMI < 25 were included as the control group. Multiplex PCR was conducted to investigate the existence of L. acidophilus , L. rhamnosus , and B. bifidum in the stool sample of the patients. Statistical analyses were performed using SPSS version 26.0. The study included 30 patients in each group of obese with diabetes mellitus (group 1), obese without diabetes mellitus (group 2), and healthy controls. The prevalence of L. acidophilus and L. rhamnosus was significantly lower in the obese groups than in the healthy controls. The prevalence of B. bifidum was higher in the control group, but the difference was not statistically significant. The study suggests that L. acidophilus and L. rhamnosus are associated with a lower risk of obesity and DM, while B. bifidum may not have a significant association with these conditions. These findings have implications for the selection and usage of probiotics in the prevention and management of obesity and diabetes mellitus. • L. acidophilus and L. rhamnosus were less common among obese and diabetic patients. • B. bifidum showed no clear link to obesity or diabetes. • Obese and diabetic groups had higher blood glucose and cholesterol levels. • Probiotics like L. acidophilus and L. rhamnosus may protect against metabolic disorders. • Gut microbiome preservation could help prevent obesity and diabetes.