Benefits
Respiratory symptom days in elite distance runners
In a double-blind, placebo-controlled crossover over 4 months of winter training, 20 elite male runners taking a daily dose of 1.26 x 10^10 reported 30 days of respiratory symptoms on the strain versus 72 on placebo. Severity was lower but not significantly. Salivary IgA, the immune measure the trial set out to raise, did not change.
Respiratory and gut symptoms in competitive cyclists
In 99 cyclists taking at least 1 x 10^9 CFU a day for 11 weeks, the effect on upper respiratory symptoms, a main aim, was too uncertain to call. In a split by sex, lower respiratory symptom load was about one third of placebo in men but was higher, with wide uncertainty, in women. Mild gut symptom episodes were about twice as frequent on the strain. The marketers co-funded it.
Skin severity scores in young children
In 56 children aged 6 to 18 months with moderate or severe atopic dermatitis, 1 x 10^9 bacteria twice daily for 8 weeks lowered severity scores within the probiotic group but not the placebo group. At 16 weeks, 92% versus 63% scored better than at baseline. The abstract reports no direct between-group score comparison.
Blood lipid levels in adults
In a 10 week placebo-controlled trial in 46 adults with total cholesterol of 4 mmol/L or more, about 8 x 10^9 CFU a day did not change LDL cholesterol more than placebo (down 7.0% versus 5.2%, not significant), and total cholesterol, HDL and triglycerides did not change.
Interferon gamma and other immune markers
These are lab markers, not health outcomes. In runners, the change in blood-culture interferon gamma was about twice that on placebo, which was not statistically significant (p = 0.07), while salivary IgA did not differ. In children, interferon gamma responses rose from baseline on the strain. In cyclists, some exercise-induced cytokine changes were smaller.
Mechanism of action
Passage through the gut
In the cyclist trial, stool lactobacillus counts rose 7.7-fold more in men on the strain than on placebo, while the rise in women was unclear. This suggests the bacteria survive the trip through the gut for a time; it does not show lasting colonization.
Binding to gut immune tissue in the lab
In laboratory tests on Peyer's patches, the immune tissue of the small intestine, the strain attached through a mannose-binding surface protein. This is cell and tissue work, not evidence of an effect in people.
Shift toward type 1 immune signaling
The runner and child trials linked the strain to a nonsignificant trend toward better-kept interferon gamma in runners and to higher responses than baseline in children, a T-helper type 1 signal. The trial authors proposed this as a possible link to the symptom findings, but these marker changes have not been shown to cause them.
Clinical trials
Double-blind, placebo-controlled crossover trial over 4 months of winter training; freeze-dried PCC (strain VRI-003) in gelatin capsules at 1.26 x 10^10 a day versus capsules with an inert excipient; stated objective was enhancement of mucosal immunity, and the listed main outcome measures included performance, immunity and respiratory illness, with no single primary named in the abstract; funding and registry not given in the abstract (Cox et al. 2010, Br J Sports Med)
20 healthy elite male distance runners in Australia.
Salivary IgA and IgA1, IL-4 and IL-12 did not differ between treatments. Runners reported 30 days of respiratory symptoms during the probiotic period versus 72 on placebo (p < 0.001), and illness severity was lower without reaching significance (p = 0.06). The change in whole-blood interferon gamma was about twofold that on placebo, not statistically significant (p = 0.07). Running performance did not change substantially.
Double-blind, randomized, placebo-controlled trial; one capsule of at least 1 x 10^9 CFU of VRI-003 PCC a day versus microcrystalline cellulose for 11 weeks; primary aim was upper respiratory and gut symptoms; funded by Chr. Hansen, Probiomics and the Australian Institute of Sport, with one author employed by each company; registered ACTRN12611000006943 (West et al. 2011, Nutr J)
99 competitive cyclists (64 men, 35 women), average age about 35; 88 completed and were analyzed.
The effect on upper respiratory symptoms had too much uncertainty for a decisive outcome. Mild gut symptom episodes and their duration were about twice as great on the probiotic. In men, lower respiratory symptom load was 0.31 times placebo (99% CI 0.07 to 0.96) and gut symptom severity was lower; in women, lower respiratory load was 2.2-fold higher with a very wide interval (0.41 to 27). These sex-specific results are subgroups.
Randomized, double-blind, placebo-controlled trial; 1 x 10^9 L. fermentum PCC (supplied by Probiomics) or placebo twice daily for 8 weeks, final check at 16 weeks; the abstract's methods print the code VRI-033 and its conclusion VRI-003; a companion paper reported immune markers from the same children (Weston et al. 2005, Arch Dis Child)
56 children aged 6 to 18 months in Perth, Australia; 53 completed (26 probiotic, 27 placebo).
The primary outcome was severity and extent by the SCORAD index. Scores fell over time in the probiotic group (p = 0.03) but not in the placebo group; the abstract gives no direct between-group test of the scores. At week 16, 92% versus 63% had a score better than baseline (p = 0.01). Interferon gamma responses rose from baseline only on the probiotic. A disease population, not healthy children.
Single-center, double-blind, placebo-controlled parallel trial of PCC L. fermentum, 2 capsules twice daily (2 x 10^9 CFU each) for 10 weeks; one author is the strain's patent inventor; funding not stated in the abstract (Simons et al. 2006, Nutr Metab Cardiovasc Dis)
46 adults in Australia with total cholesterol of 4 mmol/L or higher.
LDL cholesterol fell 7.0% on the probiotic and 5.2% on placebo, with no significant change over time or difference between groups. Total cholesterol, HDL and triglycerides did not change, nor did liver enzymes or other safety tests. One person withdrew because of bowel discomfort and three others reported it.