A Heat-Inactivated Two-Strain Lacticaseibacillus paracasei Fermented Milk as a Postbiotic for Functional...

Area of Science:

• Gastroenterology
• Microbiome research
• Clinical nutrition

Background:

• Functional constipation (FC) is prevalent in middle-aged and older adults, with limited options from current pharmacological treatments.
• Postbiotics present a potential safe alternative, but robust clinical evidence is lacking.
• This study investigates a specific heat-inactivated *Lacticaseibacillus paracasei* fermented milk as a postbiotic intervention.

Purpose of the Study:

• To evaluate the efficacy and safety of a *Lacticaseibacillus paracasei* fermented milk in adults diagnosed with functional constipation (FC).
• To assess the impact of the postbiotic intervention on spontaneous bowel movement (SBM) frequency, complete spontaneous bowel movement (CSBM) frequency, and whole-gut transit time (WGTT).
• To explore changes in constipation symptom scores, quality of life, and relevant serum biomarkers.

Main Methods:

• A 4-week randomized controlled trial involving 100 adults (aged 45-75) with Rome IV-defined FC.
• Participants received either the *Lacticaseibacillus paracasei* fermented milk or a placebo.
• Primary outcome: change in weekly SBM frequency; secondary outcomes: CSBM, WGTT, symptom scores, quality of life, and biomarkers.

Main Results:

• The postbiotic intervention did not demonstrate significant improvement over placebo for the primary outcome (SBM frequency) or key secondary outcomes (CSBM, WGTT).
• No significant differences were observed in symptom scores or quality of life between the fermented milk and placebo groups.
• Exploratory analysis revealed significant increases in serum vasoactive intestinal peptide (VIP) and acetylcholine (ACh) in the intervention group, with no reported adverse events.

Conclusions:

• Four weeks of the tested postbiotic is safe for adults with FC but does not yield significant improvements in bowel function or symptoms.
• Elevated serum VIP and ACh suggest potential engagement with neurotransmitter pathways, warranting further investigation.
• Longer-duration studies are needed to confirm the clinical efficacy and explore the mechanistic insights of this postbiotic in FC management.