PS150 is a psychobiotic originally isolated from sausage meat and has previously shown sleep benefits in animal studies, including increased REM and total sleep and mitigation of caffeine-induced insomnia. The current study employed a heat-treated, non-viable preparation.
“These findings support the idea that HT-PS150 is safe and biologically active in pathways relevant to sleep regulation and that it may hold potential as an adjunctive approach for individuals with mild to moderate insomnia,” wrote researchers from National Taiwan Sport University and other institutions in Taiwan in Nutrients.
Commenting on the findings, Dr. Miguel Toribio-Mateas, clinical neuroscientist and applied microbiologist, told NutraIngredients that the results of the study revealed meaningful, early biological changes that accurately reflect how sleep works.
“This study may not deliver a clean, headline-ready improvement in sleep scores, but that’s precisely what makes it stand out,” he said. “It exposes how unrealistic our usual outcome expectations are when we evaluate gut-brain interventions for sleep.
“But the more interesting signal sits right under the surface. The proportional responder analysis shows coordinated shifts across nocturnal melatonin, nocturnal cortisol and daytime orexin, all moving in directions that make sense if you understand sleep as a coupled circadian-arousal system rather than a single symptom score.
“In practice, that is what we typically see first with microbiota-targeted approaches, especially in people with mild baseline symptoms who are already close to what’s considered as the physiological ‘normal’.”
Regarding the subgroup findings suggesting those with higher baseline insomnia experienced greater benefits from supplementation, he noted that this “aligns with both clinical experience and the wider psychobiotic literature in the sense that these interventions rarely act as sedatives.”
“They seem to matter more when stress physiology and circadian signalling are meaningfully dysregulated,” he said. “From a translational perspective, this argues for severity-enriched recruitment and responder-based endpoints in future trials rather than ever larger samples of mildly poor sleepers.”
Dr Toribio-Mateas added that the study findings provide “a glimpse into what early biological traction looks like before symptom scales catch up.”
“It also exposes the limits of reductionist trial designs when applied to complex dietary and microbial signals,” he said
“Breaking food and fermentation down into isolated components may make studies easier to publish, but it rarely captures why whole dietary patterns and traditional fermented foods have shown such durable associations with sleep and mental health at population level. The biology is moving. Our definitions of what counts as ‘working’ may simply need to move with it.”
Postbiotic modulates melatonin and cortisol
The randomized controlled trial included 84 adults between the ages of 20 and 60 with sleep issues diagnosed using validated scales and none of whom where shift workers.
Participants received either heat-treated Limosilactobacillus fermentum PS150 (HT-PS150) or placebo for eight weeks, wore a sleep tracker each night and completed a daily sleep diary. The researchers evaluated biological samples and assessed primary sleep outcomes using the Pittsburgh Sleep Quality Index (PSQI) and the Insomnia Severity Index (ISI). Secondary outcomes included psychological, quality-of-life, gastrointestinal and overall well-being measures.
The whole cohort results revealed no significant differences between the supplement and placebo for the primary sleep outcomes. However, proportional analyses suggested that HT- PS150 modulated sleep–wake regulation by enhancing nocturnal melatonin secretion, decreasing salivary cortisol and improving daytime plasma orexin levels, a marker associated with daytime wakefulness.
In addition, those with higher baseline insomnia severity were associated with greater sleep improvements and reductions in anxiety, “suggesting potential utility in more symptomatic populations,” the researchers concluded.
Source: Nutrients. doi: 10.3390/nu18010014. “Heat-Treated Limosilactobacillus fermentum PS150 Improves Sleep Quality with Severity-Dependent Benefits: A Randomized, Placebo-Controlled Trial”. Authors: M-C. Lee et al.
