Clinical Trial Demonstrates Metabolic and Mood Benefits of Lactiplantibacillus plantarum KABP051

A randomized, double-blind, placebo-controlled clinical trial published in the Journal of Medicinal Food shows that oral supplementation with a human-derived probiotic strain, Lactiplantibacillus plantarum KABP051 from AB-BIOTICS and Kaneka Probiotics improves body composition, gut microbiota structure, and psychological parameters in healthy, overweight, and moderately stressed adults.¹ The study addresses the bidirectional relationship between metabolic health and mental wellness by utilizing a single probiotic strain capable of eliciting concurrent benefits.

The study notes that 3 million people globally are affected by obesity and depression, with a link established between gut microbiota and obesity.

Trial Design and Results

The clinical trial evaluated 60 healthy, non-depressed, overweight or obese volunteers who exhibited moderate levels of stress. Participants were randomized to receive either an active probiotic dose of 1 billion colony-forming units per day of L. plantarum KABP051 or an identical placebo capsule containing microcrystalline cellulose for a total duration of 12 weeks.

Using a mixed model for repeated measures (MMRM) alongside post-hoc analyses, researchers observed statistically significant advantages in the active group over the placebo group across three specific therapeutic metrics:

• Weight Management: Supplementation with L. plantarum KABP051 resulted in an average body weight reduction of 1.97 ± 0.77 kg relative to placebo. Concurrently, waist circumference decreased by 2.15 ± 0.81 cm compared to the placebo cohort. Post-hoc analysis also confirmed a trend toward reduction in overall body fat percentage at the 12-week threshold.
• Microbiome Modulation: Analysis indicated a significant increase in the relative abundance of Lactiplantibacillus species in the active group compared to placebo.
• Psychobiotic Outcomes: Psychological parameters, including mood, focus, and energy, were assessed using the Profile of Mood States (POMS) questionnaire. The probiotic group experienced post-hoc improvements in sub-scores for fatigue and confusion, suggesting higher energy levels and improved mood states.

There were no serious adverse events reported during the intervention timeframe.

Limitations to the study include a small sample size and lack of long-term follow up. The changes in mood were provided through self-reporting, and the study did not evaluate biomarkers to assess the underlying mechanisms.

“These results suggest that a specific strain of probiotic bacteria (L. plantarum KABP051) may have both metabolic and psychobiotic effects and may be beneficial for enhancing weight loss and body composition, improving energy (less fatigue) and mood levels while embarking on a healthy lifestyle regimen,” the researchers concluded.

What are the Implications for Ingredient Formulators?

The L. plantarum KABP051 strain is characterized by its capacity to synthesize the bioactive metabolites 2-hydroxyisocaproic acid (HICA) and 3-phenyllactic acid (PLA), which have antimicrobial properties.

AB-BIOTICS and Kaneka Probiotics explain that the results of this study highlight the potential of “psychobiotics,” which affect mood through the gut-brain axis. “Body weight and mental wellbeing are deeply interconnected, and both are strongly influenced by the gut microbiome,” stated Miquel Angel Bonachera, Executive Director and Co-Founder, AB-BIOTICS.² “This research demonstrates how these connections can be harnessed to deliver meaningful improvements in both body composition and mood with a single intervention like L. plantarum KABP-051. For many consumers, weight management is as much about feeling more energized and mentally well as it is about the physical outcomes. These effects are also linked, and by improving mood and energy levels through the gut–brain axis, L. plantarum KABP-051 may have enabled better self-regulation, supporting long-term adherence to healthier habits.”

“These are exciting results that point toward next generation probiotic solutions with the potential to transform how we support consumers on their weight management and healthy lifestyle journeys,” he noted.

References

1. Talbott S, Stephens B, Talbott J, Oddou M, Fumiki A. Effects of Lactiplantibacillus plantarum KABP051 probiotic on body composition, microbiome and mood in healthy overweight adults. J Med Food. Published online May 1, 2026. doi:10.1177/1096620X261448041
2. AB-BIOTICS, Kaneka Probiotics. Lactiplantibacillus plantarum KABP®-051 probiotic strain shows weight management and mood benefits through the gut-brain axis – new clinical study from AB-BIOTICS and Kaneka Probiotics. June 9, 2026. Accessed June 18, 2026. Press release provided via email.