Effect of fermented milk containing Lactobacillus johnsonii La1 (LC1®) on defecation in healthy Japanese adults: A double blind placebo controlled study

To elucidate the effect of fermented milk containing Lactobacillus johnsonii Lal (LC1®) on defecation, a double blind placebo controlled study was conducted. Healthy Japanese adults (24-67 years of age, n = 57, male: 31,female: 26) were randomly divided into two groups, and the subjects in the LC1 group (n = 30) consumed LC1 fermented milk containing L. johnsonii Lal at 1 x 10 9 cfu/90 g (90 g per day) for 21 days and the subjects in the control group (n = 27) consumed placebo fermented milk without the Lal strain in the same manner. In the subjects of the LC1 group with mild constipation (n = 9), less than one defecation per day in the 3 weeks observation period, defecation frequency both in times per week and days per week significantly increased during consumption of LC1 compared to before consumption (p < 0.05), and the frequency recovered to normal status with at least one defecation per day in 4 out of 9 of subjects (44%) after 3 weeks LC1 consumption. Subjects with mild constipation in the control group (n = 7) showed no significant changes in defecation frequency. The frequency in the subjects with normal defecation did not change in either group. L. johnsonii Lal was found in all feces from 10 subjects in the LC1 group participating in fecal collection, suggesting that Lal strain efficiently reached the gastrointestinal tract as a viable form. Excess amount (360 g per day) of LC1 intake for 2 weeks in the other healthy subjects (n = 10) caused an increase in defecation frequency, which was kept at the normal level of less than twice per day. These results suggest that LC1®, a probiotic fermented milk containing L. johnsonii Lal, is beneficial for improving mild constipation without any safety concerns.