Benefits
Upper respiratory health in older adults compared with milk
Two small studies in healthy older adults compared 90 g a day of this yogurt with 100 mL of milk for 8 or 12 weeks. Fewer yogurt eaters caught a cold, but neither study was significant on its own; only the pooled result was (odds ratio 0.39). Blinding was not reported, all authors were Meiji staff, and a larger later trial found no effect on flu.
Winter respiratory outcomes in a large trial of women healthcare workers
In an open-label trial of 961 women healthcare workers, a 112 mL drink of this yogurt daily for 16 weeks did not lower the rate of seasonal flu, the main outcome (7.5 percent versus 7.7 percent with no yogurt). Natural killer cell activity did not differ; serum interferon gamma rose more in the yogurt group. Meiji funded the trial.
Antibody response to seasonal vaccination, an immune marker
In two placebo-controlled trials in young and middle-aged adults, 112 mL a day of this drinkable yogurt was followed by higher antibody titers to some, not all, vaccine strains than acidified milk. Titers are a marker, not proof of fewer infections. Days with respiratory symptoms were fewer, a secondary count; the number of people with symptoms did not differ.
Natural killer cell activity and salivary IgA, immune markers
Natural killer cell activity rose more than with milk only when two studies in older adults were pooled; it did not differ in a large trial and was lower than placebo at one time point in a fatigue trial. In older nursing home residents, total salivary IgA did not differ from yogurt made with another strain; IgA bound to one of three flu strains was higher. These are markers only.
Self-rated fatigue in men during late summer
In a placebo-controlled trial of 49 men who felt tired every summer, 100 mL a day for 12 weeks lowered 4 of 13 self-rated symptom scores, including fatigue, compared with acidified milk at week 12. Two other questionnaires named as main outcomes did not differ, and the results were not corrected for multiple comparisons. All authors were Meiji staff.
Self-rated sleep quality in a secondary analysis
In a secondary analysis of the open-label trial in 961 women, sleep quality scores improved slightly more with the daily yogurt drink than with no yogurt, as did general health, vitality and constipation scores. Participants knew which group they were in, and the authors note that the yogurt ban may have stressed the control group.
Mechanism of action
Exopolysaccharide as the proposed active part
Among 139 bulgaricus strains screened, OLL1073R-1 made the most exopolysaccharide and was the only one to trigger interferon gamma from immune cells in the lab. Its acidic fraction, a phosphopolysaccharide of glucose, galactose and phosphorus, raised natural killer cell activity when fed to mice, and yogurt made with another starter pair did not.
Natural killer cell and interferon gamma signaling in mice
In mice, the exopolysaccharide raised natural killer cell activity through interleukin 12 and 18 driven interferon gamma, and the effect disappeared in mice lacking interferon gamma or the MyD88 signaling protein. Fed before infection, the yogurt and its acidic fraction prolonged survival after influenza virus exposure in mice. These are animal findings.
A large, defined polysaccharide structure
The strain's neutral exopolysaccharide is a large molecule of about 5 million g/mol made of glucose and galactose in a defined repeating unit. How such a molecule acts after it is eaten in yogurt has not been shown in people.
Clinical trials
Two comparative studies (Funagata, 8 weeks in 2005; Arita, 12 weeks in 2006 to 2007) of 90 g of OLL1073R-1 yogurt once daily versus 100 mL of milk; groups comparable in age and sex, randomized in Funagata, in Arita 17 of 112 recruits were assigned selectively and the 85 analyzed were randomized; blinding not reported; no trial registration given; all six authors worked for Meiji Dairies, which made both foods, and no outside grant was received (Makino et al. 2010, Br J Nutr)
142 healthy older adults analyzed: 57 in Funagata (median age 74.5) and 85 in Arita (median age 67.7).
Colds (plus flu in Funagata) were less frequent with yogurt in each study, but neither result was significant alone (odds ratio 0.29, p = 0.103; odds ratio 0.44, p = 0.084). Pooled across both studies, the odds were lower with yogurt (odds ratio 0.39, p = 0.019), and natural killer cell activity rose more than with milk (p = 0.028). Neither study named a primary outcome. No food-related adverse events were reported.
Randomized, open-label trial; 112 mL of Meiji Probio Yogurt R-1 drink daily for 16 weeks (November 2016 to March 2017) versus no yogurt, with all participants told to avoid other yogurt and fermented dairy; registered UMIN000023932; funded by Meiji under contract with the first author's company, with no Meiji employee authors; sleep and quality of life results come from a 2021 secondary analysis of the same trial (Kinoshita et al. 2019, Food Funct)
961 women aged 20 to 71 working in medical institutions in Ehime, Japan, mainly nurses; 479 yogurt, 482 control.
Seasonal flu, the main outcome, did not differ (cumulative incidence 7.5 percent with yogurt, 7.7 percent without). Natural killer cell activity did not differ (p = 0.11); serum interferon gamma rose more with yogurt (p = 0.03), and other immune markers did not differ. In the secondary analysis, sleep quality index scores improved more with yogurt (5.50 to 5.03 versus 5.33 to 5.22, p < 0.01), as did general health, vitality and constipation scores.
Two randomized, double-blind trials; 112 mL a day of drinkable yogurt fermented with OLL1073R-1 and S. thermophilus OLS3059 (at least 3.3 mg exopolysaccharide) versus acidified milk, starting 3 weeks before seasonal flu vaccination; registered retrospectively in May 2020 as UMIN000040232 and UMIN000040233, with antibody titers as the primary outcome; Meiji funded both trials and supplied the foods and 5 of 11 authors worked for Meiji (Hemmi et al. 2023, Biosci Microbiota Food Health)
Trial 1: 49 male university students (2012 to 2013 season). Trial 2: 64 adults aged 20 to 59 with low baseline titers (2013 to 2014 season), 30 per group analyzed.
Antibody titers, the measured outcome, were higher with yogurt for some strains: H3N2 and B in trial 1 (where H1N1 and B titers already differed between groups before intake, and 9 of 49 were dropped or excluded), and H1N1 at week 6 and B from week 3 to 12 in trial 2, with no difference for H3N2 in trial 2. No one caught flu during intake in trial 2. Cumulative days with respiratory symptoms were 22 versus 45 (p = 0.006), while the number of people with symptoms (5 versus 6) did not differ.
Randomized, double-blind, placebo-controlled trial, June to September 2015; 100 mL a day of yogurt fermented with OLL1073R-1 and S. thermophilus OLS3059 (at least 2.9 mg exopolysaccharide per 100 mL) versus acidified milk for 12 weeks; registered UMIN000025532 in January 2017, after the trial ended; all six authors were Meiji employees and no external funding was received (Makino et al. 2018, Nutrients)
49 healthy male desk workers aged 30 to 49 who felt fatigued every summer, selected for natural killer cell activity near the median; 25 yogurt, 24 placebo.
Primary outcomes were symptom ratings (13 visual analog items, POMS, Face Scale) and natural killer cell activity. At week 12, 4 items (general malaise, feeling languid, fatigue, psychological stress) were lower than placebo; the other items, POMS and Face Scale did not differ. Natural killer cell activity was lower with yogurt at week 6. Colds did not differ (16.0 versus 20.8 percent, p = 0.73).
Double-blind, parallel-group randomized trial in two nursing homes; 100 g of OLL1073R-1 yogurt every morning for 12 weeks versus yogurt made with a different Lactobacillus strain; registered UMIN000028636 in August 2017, after the 2014 trial, with salivary IgA as the primary outcome; funded in part by Meiji, which made both yogurts, and by Japanese government research grants; 4 of 17 authors worked for Meiji (Yamamoto et al. 2019, Acta Odontol Scand)
107 older adult residents of two nursing homes in Japan randomized (54 and 53); 96 completed and were analyzed.
Total salivary IgA, saliva flow and IgA flow rate rose over time in both groups with no difference between them (p = 0.9 to 1.0), and overall influenza-bound IgA showed no group by time difference (p = 1.0). Analyzed by virus type, IgA bound to influenza A H3N2 was higher with OLL1073R-1 yogurt (p = 0.001); H1N1 and B bound IgA did not differ. No illness outcome was reported.