Probiotic supplementation for respiratory and gastrointestinal illness symptoms in healthy physically active...

To examine the effect of supplementation with probiotics on respiratory and gastrointestinal illness in healthy active men and women.

A randomised double-blind placebo-controlled trial was conducted. Four hundred and sixty five participants (241 males; age 35 ± 12 y (mean ± SD) and 224 females; age 36 ± 12 y) were assigned to one of three groups: Group 1 - Bifidobacterium animalis subsp. lactis Bl-04 (Bl-04) 2.0 × 10(9)colony forming units per day, CFU per day, Group 2 - Lactobacillus acidophilus NCFM and Bifidobacterium animalis subsp. lactis Bi-07 (NCFM & Bi-07) 5 × 10(9) CFU each per day) or Group 3 - placebo mixed in a drink.

The risk of an upper respiratory illness episode was significantly lower in the Bl-04 group (hazard ratio 0.73; 95% confidence interval 0.55-0.95; P = 0.022) compared to placebo. There was no significant difference in illness risk between the NCFM & Bi-07 group (hazard ratio 0.81; 0.62-1.08; P = 0.15) and the placebo group. There was a 0.7 and 0.9 month delay in the median time to an illness episode in the Bl-04 and NCFM & Bi-07 groups respectively compared to placebo (placebo 2.5 months; Bl-04 3.2 months; NCFM & Bi-07 3.4 months). There were insufficient GI illness episodes for analysis. The NCFM & Bi-07 group but not the Bl-04 group undertook significantly more physical activity (8.5%; 6.7%-10%; P < 0.003) than the placebo group.

The probiotic Bl-04 appears to be a useful nutritional supplement in reducing the risk of URTI in healthy physically-active adults.

Australia New Zealand Clinical Trials Registry: Number ACTRN12611000130965.