ALLERGIC rhinitis symptoms were significantly reduced by a heat-treated postbiotic in a new randomised controlled trial, offering fresh insight into microbiome-based approaches for this common condition.
A growing number of patients with allergic rhinitis continue to experience persistent symptoms despite standard therapies, prompting interest in alternative strategies such as probiotics and postbiotics. These approaches aim to modulate immune responses rather than simply suppress symptoms, potentially addressing underlying disease mechanisms.
Allergic Rhinitis and Unmet Treatment Needs
Allergic rhinitis, a chronic inflammatory condition of the nasal mucosa, affects millions worldwide and can impair sleep, productivity, and overall quality of life.
While antihistamines and corticosteroids remain first-line treatments, they are not universally effective and may be associated with side effects.
This has driven research into microbiota-targeted interventions, particularly strains of Bifidobacterium longum, known for their immunomodulatory properties.
Postbiotic Shows Stronger Clinical Benefit
In this double-blind, placebo-controlled trial, 72 adults aged 18–60 years with moderate-to-severe allergic rhinitis received either a live probiotic Bifidobacterium longum CECT 7347 (PRO), a heat-treated postbiotic of the same strain (POST), or placebo alongside standard medication over 8 weeks. The primary endpoint was the Combined Symptom and Medication Score (CSMS).
Results showed that the POST group achieved a statistically significant reduction in CSMS compared with placebo (p=0.022), with an average improvement 0.6 points greater than control. This corresponded to a 33.15% greater reduction, surpassing the World Allergy Organization threshold for clinically meaningful benefit.
Improvements in quality of life, measured using the Rhinitis Quality of Life Questionnaire, were also observed in the POST group.
By contrast, the PRO group demonstrated only non-significant improvements in allergic rhinitis symptoms.
Implications and Future Directions
The study highlights the therapeutic potential of postbiotics in allergic rhinitis management, particularly as adjuncts to standard care. However, limitations include the relatively small sample size and single-centre design, which may affect generalisability.
Further large-scale, multicentre trials are needed to confirm these findings and clarify mechanisms of action.
If validated, postbiotic interventions could represent a novel, well-tolerated strategy for improving allergic rhinitis outcomes.
Reference
Cardoso A et al. Effects of live and heat-treated bifidobacterium longum CECT 7347 in adults with allergic rhinitis: a randomised, double-blind, placebo-controlled trial. Allergy. 2026;DOI:10.1111/all.70360.
Featured image: Daniel Beckemeier on Adobe Stock
