Multicentre, double-blind, randomized placebo-controlled trial to evaluate the therapeutic efficacy of nutraceutical combination in the treatment of allergic rhinitis

Background: Allergic rhinitis (AR) is a widely diffused atopic disease that is hardly managed by conventional therapy, especially in the long-term. Fatty acids (FAs), which possess both anti-inflammatory and immunomodulatory properties, could be used to control AR symptoms. Objective: We aimed at evaluating the benefits (efficacy in reducing symptoms and safety) of using an oral supplement containing FAs to treat AR. Methods: We conducted a multicentre, double-blind, randomized, placebo-controlled trial across three Italian referral hospitals. A total of 417 patients with AR were randomized to one of four groups: intranasal corticosteroids (INCs) alone, INCs + oral FAs, oral FAs alone, or placebo. All patients were treated for 90 consecutive days. The following parameters were assessed at baseline (T0) and the end of the treatment (T1): Lund–Kennedy endoscopic score (LK), visual analogue scale (VAS), and Mini Rhinoconjunctivitis Quality of Life Questionnaire (MRQoLQ). One-way ANOVA with Bonferroni–Holm correction. Results: The supplement with FAs, both as monotherapy and combined with INCs, significantly improved LK, VAS, and MRQoLQ scores comparing T0 (p < 0.01) and T1. In both cases, FAs showed better outcomes compared to INCs alone and placebo (p < 0.01). No significant differences were observed between FAs monotherapy and FAs + INCs (p > 0.05). All treatments, including placebo, demonstrated some degree of improvement, but the largest effect sizes were observed in the FAs-containing groups. No serious adverse events were reported. Conclusions: Our study shows that oral FAs supplementation, alone or combined with INCs, significantly improved clinical outcomes and quality of life in AR. Because FA guaranteed benefits both as monotherapy and in combination, this suggests that the nutraceutical formulation was the primary responsible of the improvements. Larger studies incorporating mechanistic biomarkers are necessary to validate these findings and elucidate underlying immunological pathways.