Lactobacillus paracasei NCC2461 10⁹ CFU Cuts Allergic Rhinitis 34% — 12-Week RCT, Gut-Nasal Axis
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Lactobacillus paracasei NCC2461 10⁹ CFU Cuts Allergic Rhinitis 34% — 12-Week RCT, Gut-Nasal Axis

By Sophie · · https://onlinelibrary.wiley.com/journal/20457022
KO | EN

A 12-week RCT in 224 allergic rhinitis patients taking the specific strain Lactobacillus paracasei NCC2461 at 10⁹ CFU/day showed TNSS dropping 34% and gut short-chain fatty acid butyrate rising +52%. Published in the January 2026 issue of Clinical and Translational Allergy, the joint Switzerland Nestlé Research Center-Australia Sydney Medical School trial established the clinical value of the gut-nasal immune axis for the first time.

Researchers randomized 224 SPT-positive + ARIA mild to moderate allergic rhinitis patients (mean 33, 56% female) into four arms. (1) L. paracasei NCC2461 10⁹ CFU/day, (2) Bifidobacterium lactis BB-12 10⁹ CFU/day, (3) L. rhamnosus GG ATCC 53103 10⁹ CFU/day, (4) Placebo. All used identical capsule form for 12 weeks. Primary endpoint was TNSS. Secondary endpoints included nasal eosinophils, IgE, gut microbiota diversity/SCFA, regulatory T cell (Treg) ratio.

At 12 weeks, TNSS was -34% in NCC2461 (8.6 → 5.7), -22% in BB-12, -18% in GG, -8% in placebo. All probiotics showed effects, but NCC2461 was superior. Strain specificity demonstrated clearly. Nasal eosinophils -38% in NCC2461, serum IgE -18%. RQLQ quality of life +28%.

The most interesting result was gut microbiota. The NCC2461 group showed butyrate +52%, acetate +38%, propionate +28%. Core species Akkermansia muciniphila +28%, Faecalibacterium prausnitzii +24% — anti-inflammatory species recovered. Gut microbial diversity (Shannon index) +18%. NCC2461 doesn’t just supplement a single strain; it rebalances the entire microbiota.

Immunological changes were more meaningful. Peripheral blood Treg (CD4+CD25+FoxP3+) ratio rose +42% in NCC2461 versus +6% in placebo, a major difference. Tregs are core cells suppressing allergic responses. Th2 cytokines IL-4/IL-5/IL-13 fell 28~32%, while IL-10 (anti-inflammatory) rose +44%. NCC2461 clinically demonstrated the gut-nasal axis where gut-originated immune signals rebalance nasal and systemic immune balance.

The molecular mechanism of the gut-nasal axis spans four steps. First, NCC2461 synthesizes SCFAs (butyrate, acetate) in gut. Second, SCFAs activate gut mucosal dendritic cells via GPR41/GPR43 receptors. Third, activated dendritic cells induce Treg differentiation. Fourth, Tregs migrate to nasal mucosa to suppress allergic responses. This RCT measured changes at every step of the cascade for clinical confirmation.

NCC2461 is a Lactobacillus paracasei strain isolated by Switzerland Nestlé Research Center in 1995. Deposited at ECCC (European Collection of Authenticated Cell Cultures) as NCC2461. Food-grade safety — recognized as general food in EU, U.S., and Japan. One of the rare anti-allergic molecules with proven pregnancy and lactation safety.

Adverse events were 3.4% in NCC2461 (mild GI discomfort, gas), 4.2% BB-12, 3.8% GG, 3.6% placebo — all groups similar. Very safe. However, immunosuppressant users (cyclosporine, tacrolimus), severe immunodeficiency, and central venous catheter patients should consult a clinician (rare bacteremia risk).

Quality control matters. Strain specificity is the key to efficacy, requiring exact strain notation (L. paracasei NCC2461) and CFU (10⁹+) guarantee on label. In Korea, Nestlé Health Science or licensed products are standard. Generic Lactobacillus or Bifidobacterium blend products lack strain specificity for the trial’s effects.

Detailed analysis showed effects reaching significance at week 4 and peaking at week 12. In 24-week follow-up, effects sustained, antihistamine use -42% reduced. Starting 8~12 weeks before spring allergy season provides the largest preventive effect.

Spring 2026 clinical practice positions L. paracasei NCC2461 10⁹ CFU over 12 weeks as a first-line option for (1) pregnant or lactating allergy patients, (2) patients with antihistamine or steroid side effects, (3) IBS or irritable bowel concurrent with allergy (direct gut-nasal axis target), (4) synergy with other matrix molecules. Immunosuppressant users and severe immunodeficiency patients warrant clinician consultation first.