Benefits
Upper respiratory symptom duration (L. casei 431)
In a placebo-controlled trial in 1,104 healthy adults taking at least 1x10^9 CFU of L. casei 431 daily for 42 days, upper respiratory symptoms lasted 6.4 versus 7.3 days on average over the final 3 weeks. This was a secondary outcome: the main outcome, antibody response to flu vaccination, did not improve, and symptom incidence and severity did not differ. Five of the nine authors worked for Chr. Hansen.
Nasal comfort during pollen season (KW3110)
In 120 adults with seasonal nasal symptoms, heat-killed KW3110 tablets improved a few nasal and quality-of-life scores more than placebo at single time points over 12 weeks; seven of eight authors were Kirin employees. In an earlier trial in 126 people with cedar pollen allergy, nasal symptoms improved when pollen counts were low, but effects were limited at peak pollen.
Sneezing scores in children (GM-080)
In children with year-round nasal allergy, live GM-080 at 2x10^9 CFU/day for 3 months reduced sneezing and improved the investigators' global assessment versus placebo, but the total nasal symptom score did not change significantly. The effect was clearest at this middle dose of the three tested, and only 31 children were analyzed at it. GenMont co-funded the study and supplied the probiotic, and two authors work for the company.
Nasal symptoms during grass pollen season (NCC2461)
In 131 adults with grass pollen allergy, 8 weeks of NCC2461 during the pollen season did not differ from placebo on symptom scores, quality of life or allergy antibodies. An earlier crossover study in 31 adults found less nasal itching, but no change in nasal congestion, its main outcome, after a nasal allergen challenge; the comparison product was a two-strain probiotic blend, not a placebo. Nestlé researchers took part in both.
Self-rated nose, eye and head comfort (heat-killed IJH-SONE68)
In a 12-week placebo-controlled trial in 60 adults with ongoing allergy symptoms, capsules of heat-killed IJH-SONE68 grown in pineapple juice improved a self-rated symptom score more than placebo, mainly head dullness, watery eyes and nose-blowing and sneezing. The other main outcome, a rating of difficulty in daily life, did not differ, and total IgE did not change. Sone Farm funded the study.
Mechanism of action
Th1 and Th2 immune balance
Some L. paracasei strains shift immune signaling toward Th1 responses in mouse cells; GM-080 raised IFN-gamma and IL-12 in mouse spleen cells. In children taking GM-080, IgE fell only nonsignificantly, so the shift has not been shown to explain symptom changes in people.
Nasal immune markers (NCC2461)
In the 31-person nasal challenge study, NCC2461 lowered white blood cells in nasal fluid and raised allergen-specific IL-5, IL-13 and IL-10 production by blood cells, unlike a comparison two-strain blend; the authors also noted somewhat unexpected systemic immune changes. These were not confirmed by a benefit in the later pollen-season trial.
Exopolysaccharide (IJH-SONE68)
IJH-SONE68 produces an exopolysaccharide that reduced ear swelling when given by mouth to mice in a contact dermatitis model and inhibited the enzyme hyaluronidase in laboratory tests. Whether this explains the human results has not been tested.
Strain-specific effects
L. casei 431, KW3110, NCC2461, GM-080 and IJH-SONE68 were each tested separately with different doses and forms, including heat-killed cells. DG and Lpc-37 have their own pages, and 8700:2 is covered with L. plantarum HEAL9. Results from one strain cannot be assumed for another.
Vaccine response not changed
In the 1,104-person L. casei 431 trial, no part of the antibody response to flu vaccination changed, even though symptom duration was slightly shorter. How the strain might shorten symptoms was not measured.
Clinical trials
Randomized, double-blind, placebo-controlled, parallel-group trial; an acidified milk drink with at least 1x10^9 CFU L. casei 431 or placebo for 42 days, with seasonal flu vaccination on day 21; registered ISRCTN08280229 (Jespersen et al. 2015, Am J Clin Nutr).
1,104 healthy adults aged 18 to 60 at two centers in Germany and Denmark.
The primary outcome, seroprotection 21 days after vaccination, was not met, and no component of the vaccine immune response changed. Upper respiratory symptoms lasted 6.4 versus 7.3 days on average in the last 3 weeks (P = 0.0059), a secondary outcome compared between groups; incidence and severity did not differ. Five of the nine authors worked for Chr. Hansen, which sells the strain.
Double-blind, randomized, placebo-controlled trial of three doses of live GM-080 (2x10^8, 2x10^9 or 1x10^10 CFU/day) or placebo for 3 months, reported with a mouse airway study; registered ISRCTN14829274 (Lin et al. 2023, Cells).
137 children with perennial allergic rhinitis were randomized and 122 analyzed; 31 were analyzed at 2x10^9 CFU/day.
At 2x10^9 CFU/day, sneezing and Investigator Global Assessment scores improved significantly. The total nasal symptom score fell only nonsignificantly, total IgE did not change significantly, and serum IFN-gamma rose without reaching significance. The study was funded by a government research grant and by GenMont Biotech, which supplied the probiotic, and two authors are GenMont employees.
Double-blind, randomized, placebo-controlled parallel trial of capsules with heat-killed IJH-SONE68 grown in pineapple juice (1,040 mg of powder with about 5x10^5 cells, filling four capsules) or dextrin placebo for 12 weeks; people with pineapple hypersensitivity or on regular medication were excluded (Noda et al. 2021, Nutrients).
60 adults aged 21 to 70 with chronic allergy symptoms.
Self-assessed symptom scores improved more than with placebo (p = 0.008), driven by head dullness, watery eyes and nose-blowing and sneezing. The visual analogue scale for difficulty in daily life, the other primary outcome, did not differ (p = 0.380), and total IgE did not change. Adverse events did not differ between groups. Funded by Sone Farm.
Double-blind, randomized, placebo-controlled parallel trial of a daily 5 g powder sachet with 5x10^9 CFU NCC 2461 or maltodextrin placebo for 8 weeks during the 2012 Berlin grass pollen season (Nembrini et al. 2015, Clin Transl Allergy).
131 adults with grass pollen allergy confirmed by skin prick test and IgE.
No significant differences from placebo in symptom scores, quality of life or grass pollen IgE. The authors note this contrasts with two earlier allergen challenge studies. All authors were Nestlé researchers.
Double-blind, randomized crossover trial outside the pollen season; NCC2461 powder (about 1x10^10 CFU per sachet) and a blend of L. acidophilus ATCC SD5221 and B. lactis ATCC SD5219, 4 weeks each with a 6 to 8 week washout, with a nasal provocation test before and after each period; no placebo arm; registered NCT01233154 (Perrin et al. 2014, Clin Transl Allergy).
31 adults with grass pollen allergy; 28 completed.
The primary outcome, blocked nose after the allergen challenge, did not change. NCC2461 reduced self-rated itching of the nose and white cells in nose fluid, unlike the blend, and changed some blood cytokine measures, and the authors described some systemic changes as somewhat unexpected. There was no placebo arm. Seven of the 13 authors listed the Nestlé Research Center.
Double-blind, placebo-controlled study of daily KW3110 starting 1 month before the pollen season and lasting 3 months; the abstract does not state the dose or whether the cells were live (Yonekura et al. 2009, Allergy Asthma Proc).
126 patients with Japanese cedar pollen allergy.
Nasal symptoms, eosinophil cationic protein and quality of life improved in the KW3110 group when pollen levels were low, but effects were limited during the peak pollen period; the abstract does not state whether these were differences from placebo. The authors concluded that any effect is limited.
Randomized, double-blind, placebo-controlled, parallel-group trial; two tablets a day, each with at least 0.7x10^11 heat-killed KW3110 cells, or placebo for 12 weeks from January to April; registered UMIN000053239 (Sugihara et al. 2025, Front Nutr).
120 adults with mild to moderate seasonal allergic rhinitis who did not regularly use medication.
KW3110 improved more than placebo on the nasal symptoms and outdoor activities scores of the quality-of-life questionnaire, the primary outcome, at 4 weeks, on runny nose in a symptom diary at 8 weeks, and on physician-rated sneezing or runny nose and severity class at 4 weeks; the abstract reports no other significant time points. No adverse event related to the tablets was reported. Seven of eight authors were Kirin employees.