Probiotic Bifidobacterium longum BB536 and its impact on subjective symptoms of physical conditions associated with common cold-like symptoms in healthy adults: A randomized, double-blind, placebo-controlled trial

We evaluated the effect of Bifidobacterium lomgum BB536 (B. longum BB536) on subjective symptoms of the physical condition of healthy adults in a double-blind, randomized, placebo-controlled trial. Two hundred participants were recruited and randomized into two groups (BB536 group: n = 100; placebo group: n = 100) based on the frequency with which they experienced a cold during the three years prior to the study. The participants consumed either powder containing 1 x 1010 colony forming units (CFU) of B. longum BB536 or a placebo once daily for 12 weeks, and their health status was recorded in a diary. Participants who consumed B. longum BB536 had a significantly lower incidence of feverishness, a systemic symptom, than the placebo group. Our results indicate that daily intake of B. longum BB536 may contribute to maintaining physical condition in healthy adults, suggesting that B. longum BB536 may be a promising probiotic for reducing the occurrence of common cold-like symptoms.