Effect of Fermented Soybeans Containing Bacillus subtilis MC1 on Defecation, Fecal Properties and Fecal Microflora of Healthy Female Volunteers

To evaluate the effects of natto fermented by Bacillus subtilis MC1 on defecation, fecal properties and fecal microflora, a crossover study was conducted in 44 healthy volunteers (female, 34.9±8.8 years old; mean±SD). The subjects were divided into two groups and given 40g natto (B.subtilis MC1 spores 2×1010cfu) and boiled soybeans (40g/day) for 14 days each. No effect of natto was found on the frequency of defecation, the volume of feces or fecal characteristics. The number of Bacillus bacteria was significantly increased after the natto administration period in comparison with the boiled soybean administration period (p<0.05), indicating that live B.subtilis MC1 spores reached the large intestine. On the other hand, the number of other bacteria showed no change in the natto administration period in comparison with the boiled soybean administration period.