Safety Assessment of Excessive Intake of Yogurt Containing Bifidobacterium lactis Bb-12 in Normal Volunteers

A placebo-controlled, double-blind study was performed to assess the safety of excessive intake of yogurt containing more than 107 cfu/g of Bifidobacterium lactis Bb-12. Fifty-seven volunteers with fecal frequency of less than five times per week were enrolled. The effect of the food on defecation was also examined. Two-week administration of the test food (more than three times the daily recommended intake) did not affect blood pressure, hematological data, blood chemistry or urinalysis. No abnormal changes or severe adverse events related to the test food were observed. The test food significantly increased the fecal frequency of mildly constipated subjects but placebo yogurt had a similar effect. Placebo yogurt tended to reduce stool hardness while the test food increased the frequency of stool with normal hardness maintained. These data indicate that yogurt containing Bifidobacterium lactis Bb-12 is safe in healthy subjects and that it has beneficial effects on defecation in mildly constipated subjects.