Heat-inactivated Bacillus subtilis subsp. natto strain QOL (QOLbacillus natto) improves negative mood states: A randomized,double-blind, and placebo-controlled parallel study
DOI:
https://doi.org/10.31989/ffhd.v15i8.1677Abstract
Background/Objectives: Heat-inactivated Bacillus subtilis subsp. natto strain QOL (QOL bacillus natto) is a bacterial strain isolated from the fermented food natto and is produced through heat sterilization following pure culture. QOL bacillus natto has been reported to improve sleep quality in healthy adults, and to improve depression-like behavior
caused by social defeat stress in animal models. However, there is a lack of research investigating the effects of QOL bacillus natto on psychological stress related to desk work. The purpose of this study was to evaluate the effects of QOL bacillus natto intake on psychological stress in healthy adults prone to fatigue and stress caused by daily desk work.
Methods: A randomized, double-blind, placebo-controlled, parallel-group study was conducted on 112 healthy adult males and females aged 24 to 89 years. Participants were randomly assigned to receive either a test food containing QOL bacillus natto (100 mg) or a placebo daily for 8 weeks. Participants were assessed at weeks 0 and 8 using the
Profile of Mood States 2nd Edition (POMS2), the Ogu-ri-Shirakawa-Azumi Sleep Inventory MA version (OSA-MA), and stress intensity using visual analog scale (VAS).
Results: After 8 weeks of intervention, the Total Mood Disturbance (TMD) score in POMS2 for the QOL bacillus natto group was below the mean value, and significantly lower than that of the placebo group. Additionally, the Vigor-Activity score in POMS2 for the QOL bacillus natto group was above the mean value, and significantly higher than that of the placebo group.
Conclusions: The results suggested that QOL bacillus natto intake enhances vigor and activity, improves negative mood states, and is effective in reducing psychological stress.
Trial registration: jRCT1030240202
Keywords: Bacillus subtilis; QOL bacillus natto; Postbiotics; Stress; Negative mood states; POMS
Downloads
Published
Issue
Section
License
Copyright (c) 2025 Functional Foods in Health and Disease - Online ISSN: 2160-3855; Print ISSN: 2378-7007
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Authors retain the copyright of their articles and grant the Functional Food Center (FFC) and its journals the right of first publication under the terms of the Creative Commons Attribution 4.0 International License.
This license permits unrestricted use, distribution, and reproduction in any medium, including commercial use, provided the original author(s) and source are properly credited. Authors may post and share their published work freely, provided that the original publication in this journal is acknowledged.
By submitting to this journal, authors confirm that their manuscripts are original, not under consideration elsewhere, and that they hold the necessary rights to grant this license. The Functional Food Center encourages open scientific exchange and allows derivative and extended works, provided attribution to the original publication is maintained.