BACKGROUND/AIMS: Probiotics are expected to confer benefits on patients with constipation, but how probiotics act on constipated patients with variable stool consistencies remains unclear. We investigated the effect of strain Shirota (LcS) on constipation-related symptoms, especially stool consistency, of constipated patients.

METHODS

Constipated patients meeting the Rome III criteria were divided into 3 groups according to the Bristol Stool Form Scale (BSFS): hard (hard stool [HS], BSFS ＜ 3), normal (normal stool [NS], ≤ 3 BSFS ≤ 4), and soft (soft stool [SS], 4 ＜ BSFS ≤ 5) stools. Subjects in each group consumed a probiotic beverage containing 10¹⁰ colony-forming units of LcS daily for 28 days.

RESULTS

LcS intervention significantly alleviated constipation-related symptoms and increased defecation frequency in all subjects. Four weeks of LcS supplementation softened the hard stools in HS, hardened the soft stools in SS, and did not alter the ideal stool consistency in NS. The short-chain fatty acid (SCFA) concentrations were highest in SS, followed by NS and HS. LcS intervention increased the stool SCFA levels in HS but reduced or did not alter the levels in NS and SS. LcS intervention increased the and abundances in HS and decreased the abundance in SS.

CONCLUSIONS

LcS supplementation improved the constipation-related symptoms in constipated subjects. Differences in baseline stool consistency could result in different anti-constipation effects of LcS intervention. LcS balanced the stool consistency-softened the HS and hardened the SS. These effects could be associated with modulation of the gut microbiota and SCFA production.