The gut microbiota is a crucial modulator of health effects elicited by food components, with SCFA (short chain fatty acids), especially butyrate, acting as important mediators thereof. We therefore developed a nutritional synbiotic composition targeted at shifting microbiome composition and activity towards butyrate production. An intestinal screening model was applied to identify probiotic Bacillus strains plus various amino acids and peptides with suitable effects on microbial butyrate producers and levels. A pilot study was performed to test if the synbiotic formulation could improve fecal butyrate levels in healthy humans. A combination of Bacillus subtilis DSM (Number of German Collection of Microorganisms and Cell Cultures) 32315 plus L-alanyl-L-glutamine resulted in distinctly increased levels of butyrate and butyrate-producing taxa (Clostridium group XIVa, e.g., Faecalibacterium prausnitzii), both in vitro and in humans. Moreover, circulating lipid parameters (LDL-, and total cholesterol and LDL/HDL cholesterol ratio) were significantly decreased and further metabolic effects such as glucose-modulation were observed. Fasting levels of PYY (Peptide YY) and GLP-1 (Glucagon-like Peptide 1) were significantly reduced. In conclusion, our study indicates that this synbiotic composition may provide an effective and safe tool for stimulation of intestinal butyrate production with effects on e.g., lipid and glucose homeostasis. Further investigations in larger cohorts are warranted to confirm and expand these findings.

Specialized pro-resolving mediators (SPM) have emerged as crucial lipid mediators that confer the inflammation-resolving effects of omega-3 polyunsaturated fatty acids (n-3 PUFA). Importantly, SPM biosynthesis is dysfunctional in various conditions, which may explain the inconclusive efficacy data from n-3 PUFA interventions. To overcome the limitations of conventional n-3 PUFA supplementation strategies, we devised a composition enabling the self-sufficient production of SPM in vivo. Bacillus megaterium strains were fed highly bioavailable n-3 PUFA, followed by metabololipidomics analysis and bioinformatic assessment of the microbial genomes. All 48 tested Bacillus megaterium strains fed with the n-3 PUFA formulation produced a broad range of SPM and precursors thereof in a strain-specific manner, which may be explained by the CYP102A1 gene polymorphisms that we detected. A pilot study was performed to test if a synbiotic Bacillus megaterium/n-3 PUFA formulation increases SPM levels in vivo. Supplementation with a synbiotic capsule product led to significantly increased plasma levels of hydroxy-eicosapentaenoic acids (5-HEPE, 15-HEPE, 18-HEPE) and hydroxy-docosahexaenoic acids (4-HDHA, 7-HDHA) as well as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in healthy humans. To the best of our knowledge, we report here for the first time the development and in vivo application of a self-sufficient SPM-producing formulation. Further investigations are warranted to confirm and expand these findings, which may create a new class of n-3 PUFA interventions targeting inflammation resolution.

Beneficial health effects of omega-3 polyunsaturated fatty acids (n-3 PUFA) are partly attributed to specialized pro-resolving mediators (SPMs), which promote inflammation resolution. Strategies to improve n-3 PUFA conversion to SPMs may, therefore, be useful to treat or prevent chronic inflammatory disorders. Here, we explored a synbiotic strategy to increase circulating SPM precursor levels. Healthy participants (n = 72) received either SynΩ3 (250 mg eicosapentaenoic acid (EPA) plus docosahexaenoic acid (DHA) lysine salts; two billion CFU Bacillus megaterium; n = 23), placebo (n = 24), or fish oil (300 mg EPA plus DHA; N = 25) capsules daily for 28 days in a randomized, double-blind placebo-controlled parallel 3-group design. Biomarkers were assessed at baseline and after 2 and 28 days of intervention. The primary analysis involved the comparison between SynΩ3 and placebo. In addition, SynΩ3 was compared to fish oil. The synbiotic SynΩ3 comprising Bacillus megaterium DSM 32963 and n-3 PUFA salts significantly increased circulating SPM precursor levels, including 18-hydroxy-eicosapentaenoic acid (18-HEPE) plus 5-HEPE, which was not achieved to this extent by fish oil with a similar n-3 PUFA content. Omega-3 indices were increased slightly by both SynΩ3 and fish oil. These findings suggest reconsidering conventional n-3 PUFA supplementation and testing the effectiveness of SynΩ3 particularly in conditions related to inflammation.

The gut–brain axis plays a pivotal role in mental health, with synbiotic supplements emerging as promising interventions for stress and anxiety management. This observational open-label pilot study aims to evaluate the effects of a symbiotic supplement containing Bacillus subtilis DSM 32315 and L-alanyl-L-glutamine, delivered via a targeted colonic-release capsule, on stress, anxiety, and mental wellbeing. Conducted as a non-placebo-controlled real-world case study, the study recruited 100 adults with elevated perceived stress and followed them for over eight weeks. Validated self-reporting tools, including the Depression Anxiety Stress Scales-21 items (DASS-21), Perceived Stress Scale-10 items (PSS-10), Athens Insomnia Scale (AIS), Short Form Health Survey-12 items, and Gastrointestinal Symptom Rating Scale questionnaires, were used to assess outcomes. Statistical analyses, primarily using linear mixed models, indicated reductions in DASS-21, PSS-10, and AIS scores, along with self-reported improvements in gastrointestinal symptoms and mental well-being. These findings should be interpreted cautiously due to the exploratory, uncontrolled study design. Notably, DASS-21 total scores declined within one week, with reported benefits sustained at four and eight weeks. However, these rapid changes may partly reflect expectancy effects or regression to the mean. These observations provide valuable insights for further hypothesis generation, notably that the synbiotic supplement could support stress management and mental health by modulating the gut–brain axis. However, further placebo-controlled trials including measurement of relevant biomarkers are warranted to confirm these observations and explore underlying mechanisms.

Aging is accompanied by progressive functional decline and morphological defects of cholinergic neurons. Some probiotic bacteria with proficiency for biofilm formation in the gut are being discussed as potentially neuroprotective. Here, we screened Bacillus subtilis (B. subtilis) strains for biofilm production, using an in vitro assay. Thereafter, a transgenic Caenorhabditis elegans (C. elegans) strain with its cholinergic neurons expressing green fluorescent protein (GFP) was fed for up to 15 days on either the identified biofilm-producing B. subtilis strain B4U 50 or the control B. subtilis strain 168, with or without addition of a standardized Ginkgo biloba preparation. The morphology of the cholinergic neurons was monitored at several consecutive days by fluorescence microscopy. The occurrence of morphological defects such as knots and ruptures within the axons of cholinergic neurons, as observed with increasing age, was significantly lower in nematodes provided with the B4U 50 strain. Even worms whose diet was switched to B4U 50 later in life showed less damage of their neurons, as compared to worms fed on the control strain. Supplementation with the Ginkgo biloba preparation was neuroprotective in worms fed on either B. subtilis strain, while a stronger beneficial effect was observed upon combined administration of B. subtilis B4U 50 and the Ginkgo biloba preparation. In conclusion, feeding a B. subtilis strain proficient for biofilm formation, B4U 50, was neuroprotective when compared to a diet consisting of control B. subtilis, delaying the onset of aging-associated morphological defects in cholinergic neurons of C. elegans. Graphical Abstract