Safety Evaluations of Long-Term and Excessive Intakes of <i>Bifidobacterium longum</i> CLA8013: A Placebo-Controlled, Randomized, Double-Blind Study

Heat-killed Bifidobacterium longum CLA8013 has been demonstrated to improve the frequency of defecation, straining, and pain during defecation in human placebo-controlled, double-blind, parallel-group studies. We conducted a randomized, double-blind, placebo-controlled, parallel-group study to evaluate the safety of both long-term and excessive intakes of heat-killed B. longum CLA8013, when used as a food with functional claims. In both tests, 30 healthy volunteers were divided into two groups: an active group that ingested heat-killed B. longum CLA8013 and a placebo group. In the long-term intake safety study, participants in the active group ingested 25 billion cells/day for 12 weeks. In the excessive intake safety study, participants in the active group ingested 125 billion cells/day for 4 weeks. Physical, hematological, biochemical, and urine examinations were conducted, and adverse events were evaluated in both studies. The studies revealed no abnormalities in any of the safety tests. In conclusion, no safety-related issues were identified with long-term or excessive intake of heat-killed B. longum CLA8013.