Findings of the randomised, double-blind placebo-controlled, parallel-group study was published in The American Journal of Gastroenterology.
This study was conducted on outpatients attending the Department of Gastroenterology at the Juntendo Tokyo Koto Geriatric Medical Center.
In total, 80 seniors aged 65 or older and diagnosed with chronic constipation were randomised to receive either probiotics or placebo powder sachet daily for four weeks.
Significant improvement was in the CSS score was seen in the intervention group by the end of the trial and even four weeks after the trial has ended.
Specifically, CSS score dropped from 10.26 ± 3.29 to 7.78 ± 4.30 at week four and went up slightly to 8.43 ± 3.52.
No significant changes in the CSS score were reported in the placebo group. Even so, the differences in the CSS score between the intervention and placebo groups were not statistically different.
“Although there was no intergroup difference in the total CSS (the primary outcome), we observed an improvement in the patients' bowel movements and upper abdominal symptoms after 4 weeks of BB536 intake compared with the placebo group,” the researchers said.
In terms of bowel movement improvements, the researchers were specifically referring to improvements in stool frequency. For instance, stool frequency had improved from 0.89 ± 0.88 to 0.47 ± 0.94 by the end of the study in the intervention group.
No significant changes were reported in the placebo group.
In addition, there were significant differences between the intervention and placebo groups in terms of “failure of evacuation” – which refers to unsuccessful attempts in emptying the bowels for every 24 hours.
For the intervention group, “failure of evacuation” reduced from 0.83 ± 0.45 to 0.61 ± 0.96 by the end of the trial. This maintained at a figure lower than the baseline – at 0.72 ± 0.74, even four weeks after the intervention was over.
Again, no significant changes were seen in this aspect for the placebo group.
Explaining the reason for supplementing Bifidobacterium probiotics, the researchers said that next-generation sequencing has showed a reduction of Bifidobacteria in the stools of elderly.
It has also been found to be effective for abnormal bowel movements when given with dairy products.
“To the best of our knowledge, this is the first study to see a prolonged effect of probiotics on constipation and upper abdominal symptoms in elderly patients with chronic constipation.
“This prolonged effect may be caused by the improvement of the intestinal environment owing to the 4-week probiotic intake,” the researchers concluded.
Gut microbiota composition
The improvement in bowel movement in the intervention group might be due to the metabolites produced by the probiotics, rather than changes in the microbiota, the researchers said.
This is because analysis based on the genus level showed no significant difference in the gut microbiota between the groups, as well as in the groups before and after the study.
Secondly, the researchers came to the above conclusion based on the correlation between Coprococcus – a bacteria that tends to be positively correlated with the CSS score – and the actual changes in CSS score.
“We found that the relative abundance of Coprococcus tended to have a positive correlation with the CSS score at week 4 in the BB536 group; however, there was no obvious difference in the changes in the CSS scores from baseline between the Coprococcus-increased group and Coprococcus-decreased group, and there was no correlation of Coprococcus with the CSS score at 0 weeks.
“Our data suggest that the relative abundance of this genus did not seem to affect the CSS score.
“This suggests that changes in metabolic and physiological pathways mediated by bacterial components and metabolites such as acetic acid of BB536, rather than changes in the composition of the microbiota, may affect defecation,” they said.
The researchers added that similar observations were made by Kaczmarczyk M at el, who found that probiotic intervention modified the biochemical and physiological parameters, regardless of changes in microbiota composition and metabolic function over time.
They also cited McNulty et al, who similarly observed a change in the metabolic functions of the microbiota under the influence of probiotics, despite no change in its composition.
For future studies, the researchers said it would be necessary to examine a large number of cases at multiple institutions and to analyse metabolites such as organic acids in the intestinal tract.
Source: The American Journal of Gastroenterology
Usefulness of Bifidobacterium longum BB536 in Elderly Individuals With Chronic Constipation: A Randomized Controlled Trial
Authors: Takeda et al