Researchers from Greece, Australia, and Italy noted that the reduction in fasting glucose occurred without a parallel rise in insulin, suggesting improvements in the regulation of endogenous glucose production or enhanced insulin sensitivity.
“The relevance of these findings is particularly noteworthy in the context of subthreshold depression,” they wrote. “Beyond psychological manifestations, accumulating evidence indicates that individuals with subthreshold depressive symptoms frequently present with subtle metabolic and inflammatory disturbances, including alterations in glucose regulation and low-grade systemic inflammation.”
Metabolic endotoxemia
Metabolic endotoxemia is a condition characterized by increased levels of bacterial toxins circulating in the bloodstream. These endotoxins are lipopolysaccharides (LPS), components of the outer membrane of gram-negative bacteria.
LPS enters the bloodstream through the gut barrier, when it becomes more “leaky” (intestinal permeability), causing chronic low-grade inflammation. Metabolic endotoxemia has been linked to obesity, diabetes, and non-alcoholic fatty liver disease.
In addition, previous research suggests that endotoxemia coupled with inflammation may predict and fuel subsequent depression.
The current study results indicated that the probiotics may reduce lipopolysaccharide levels and improve gut barrier integrity.
“Given the well-established role of endotoxemia in impairing insulin signalling and contributing to metabolic dysregulation, these anti-inflammatory shifts likely further contributed to the observed improvements in glucose homeostasis,” the researchers wrote.
Study details
The study was a secondary exploration from a previously published double-blind, randomised placebo-controlled trial that evaluated a probiotic’s effects on psychosocial outcomes in adults with subthreshold depression.
The parent study also examined metabolic markers, such as glucose and insulin, in addition to mental health outcomes.
The 39 adult participants were assigned either a daily multi-species probiotic provided by the study sponsor, Biome Australia Trading Pty Ltd., and marketed as Biome Lift in Australia and as Bifizen in the USA and Europe, or a placebo.
The researchers assessed metabolic, inflammatory, and hormonal markers at 6 and 12 weeks and evaluated dietary intake, physical activity, and anthropometric measurements.
The findings showed that the probiotic group had significantly reduced fasting glucose at 12 weeks compared with placebo.
The probiotic group also showed greater reductions in glucose-dependent insulinotropic peptide, a marker associated with insulin resistance and obesity.
Plasma SCFA concentrations “remained largely unchanged,” the researchers wrote.
They called for future studies with larger sample sizes and controlled dietary conditions to clarify specific microbial pathways and identify which populations may likely benefit from probiotic interventions.
Source: Nutrients, https://doi.org/10.3390/nu18071025, “Modulation of Glucose Homeostasis, Metabolic Endotoxemia and Circulating Short-Chain Fatty Acids Following Multi-Species Probiotic Supplementation: Findings from a 12-Week Randomised Placebo-Controlled Trial.” Authors: G. Moschonis et al.
