To estimate the health-promoting effects of Lacticaseibacillus paracasei (previously Lactobacillus casei) strain
Shirota (LcS) that reached the lower gastrointestinal tract alive, we investigated the characteristics of gut microbiome,
organic acid profiles, defecatory symptoms and serum viral antibody indexes of healthy Japanese adults between the
group in whom live LcS was detected or not from stool. The β-diversity index of the gut microbiome constituted
a significant difference between the live-LcS-detected-group (LLD) and the live-LcS-not-detected-group (LLnD).
In the LLD, the Bifidobacteriaceae, Lactobacillaceae, and Coriobacteriaceae counts were significantly higher, and
the succinate concentration was significantly lower than that in the LLnD. The serum herpes simplex virus (HSV)
immunoglobulin (Ig)M antibody index in the LLD tended to be lower than that of the LLnD in HSV IgG-positive
subjects. Of the LLD, those in the fermented milk products containing LcS (FML)-high-frequency-group (FMLHF) and those in the FML-low-frequency-group (FML-LF) had different gut microbiome and organic acid profiles.
However, the pattern of differences between FML-HF and FML-LF was dissimilar those between LLD and LLnD.
In contrast, among subjects with FML-LF, those in the group with LLD in stool (LF-LLD) and those in the LLnD in
stool (LF-LLnD) showed a similar pattern of differences in their gut microbiome and organic acid profiles as those
in the LLnD and LLD. The LLD and LF-LLD commonly had lower caloric and carbohydrate intakes from the diet
than their respective control groups. In this study, we found that the presence of live LcS in stool is associated with
a healthy gut environment and inhibition of the reactivation of latently infected viruses in the host. However, these
health-promoting effects on the host were not related to the frequency of FML intake. Furthermore, dysbiosis of
the gut microbiome and diet including caloric intake was related to the viability of ingested LcS in the gut. CLICK TO REVIEW