Changes in gut microbiota composition are said to influence the beneficial effects of probiotics on disease conditions.
Based on this, researchers at the Sanjay Gandhi Postgraduate Institute of Medical Sciences conducted a study to assess the composition of faecal microbiota and host immune responses in peripheral blood.
They assessed 14 healthy women at three time points: before and after the administration of a probiotic preparation known as VSL#3 (each capsule containing 112.5 billion freeze-dried bacterial cells from eight species) twice daily for four weeks, and four weeks after the probiotic administration had been discontinued.
The administration of VSL#3 did result in a reduction in the relative frequency of circulating Th17 cells, which are partly responsible for inflammation in the body.
The researchers noted, however, that there was no effect on the relative frequencies of other pro-inflammatory cells, particularly Th1, Th2 and T regulatory cells.
They wrote: "These findings suggest that the beneficial anti-inflammatory effect of this preparation in patients with autoimmune and allergic disorders may be related to reduced production of monocyte-derived cytokines, rather than to changes in the composition of gut microbiota."
Limitations of administration
The researchers also acknowledged the limitations of the study, one of which was the single population group involved in the study. As gut microbiota tends to vary across geographical regions and according to factors such as dietary habits, the study's results could not be extrapolated to other population groups.
They concluded: "Further similar studies in other populations may be warranted. Our study included only young women; this was done to ensure homogeneity of the study subjects, and it is unlikely that this by itself would have influenced the effect of probiotic administration.
"Overall, we found that administration of VSL#3 did not lead to any change in gut microbiota or in the frequencies of Th1, Th2 and T regulatory cells in healthy women. Hence, it is unlikely that this probiotic preparation can be used to induce changes in the composition of gut microbiota in healthy subjects.
"However, it led to a reduction in the frequency of Th17 cells. These immune changes may be involved in its beneficial effect in immuno-inflammatory disorders."
Source: BMC Gastroenterology
"Effect of administration of a probiotic preparation on gut microbiota and immune response in healthy women in India: an open-label, single-arm pilot study"
Authors: Ankita Singh, et al.