The gastrointestinal status of healthy adults: a post hoc assessment of the impact of three distinct probiotics

Abstract

There is a growing awareness that supplementation with probiotic bacteria can impart beneficial effects during gastrointestinal disease, but less is known about the impact of probiotics on healthy subjects. Here, we report the outcomes of a post hoc analysis of recorded daily gastrointestinal events and bowel habits completed by healthy adults participating in a placebo-controlled, single-centre, randomised, double-blind, quadruple-arm probiotic tolerability study. Extensive screening ensured the healthy status of subjects entering the study and during a 2-week pre-intervention run-in period, a burden of gastrointestinal events (stomach pains, indigestion, acid reflux, stomach tightening, nausea and vomiting, stomach rumbling, bloating, belching and flatulence) was identified suggesting GI discomfort within the population. In the subsequent 12-week intervention period with 3 distinct probiotic formulations and a matched-placebo, reductions in the incidence rates of bloating, borborygmus, stomach pains, slow faecal transit and incomplete defecations were observed in the probiotic groups compared to the placebo. These results highlighted differing responses among the probiotic formulations tested and indicated potential anti-constipation effects. Product specific modulations in circulating interleukin-6 levels and in the composition of the gut microbiota were also detected. Together, these data suggest a role for probiotic supplementation to exert beneficial effects on the gastrointestinal functioning of healthy subjects and highlight the need for further longer-term studies in healthy populations to gain a greater understanding of the impact of probiotics.

A double‐blind, randomized, placebo‐controlled study assessing the impact of probiotic supplementation on the symptoms of irritable bowel syndrome in females

“…Participants on the probiotic reported 35% fewer loose stools during the intervention period which indicates a potential anti‐diarrhoeal effect and in a Lab4 study with school children (aged 3–10) there was a 44% reduction in the incidence of watery/loose stools 35 . In contrast, in the current IBS study, there were fewer “incomplete” defecations (feeling of incomplete evacuation or failure to defecate) in the probiotic group compared to the placebo group which could be considered to be an “anti‐constipation” outcome and similar outcomes have been observed in a Lab4 study with healthy adults 18 . These data suggest the “normalization” of stool form and this was evidenced by the greater incidence of stools with normal form in the Lab4 group.…”

“…It has been found that the diversity of the IBS gut microbiota differs from that of healthy subjects 5,6,54–56 particularly in females 57 . Comparison of the baseline alpha diversity of the IBS cohort from this study with that of age, gender and/or geographically matched non‐IBS populations from previous studies with the Lab4 probiotic 18,30 showed the alpha diversity of the IBS population was significantly lower (Figure S8). There was a trend towards higher diversity in the active group at the end of the study, but not the placebo.…”

“…In the probiotic group, the IBS‐SSS reduction was associated with fewer days with abdominal pain, reduced pain and bloating severity, and improvements in bowel habit dissatisfaction and general well‐being. A study with healthy adults receiving Lab4 also reported reductions in abdominal pain and bloating and improvements in bowel habits 18 . Zhang et al showed in a network analysis of IBS randomized control trials that single‐strain probiotics of Lactobacillus acidophilus alleviated gastrointestinal symptoms (particularly bloating) and improved quality of life 10 .…”

“…The vast majority of individuals with IBS do not present with any demonstrable intestinal abnormalities or inflammation but elevations in circulating pro‐inflammatory cytokines, such as IL‐6, have been observed 51 . Healthy adults taking the Lab4 probiotic had improvements in gastrointestinal symptoms and bowel habits that were associated with reduced circulating levels of plasma IL‐6 18 and another Lab4 ex vivo study showed reduced IL‐6 secretion by peripheral blood mononuclear cells 52 . In the current study, the baseline plasma IL‐6 levels were within the normal range 53 and remained unchanged.…”

“…Monitored using an adapted version of a recognized daily bowel habit diary 18 (Figure S3). Participants recorded (i) the date of attempted defecation, (ii) whether a stool was passed, (iii) whether there was an urgent need to defecate, (iv) whether there was straining to start the defecation, (v) whether there was a feeling of incomplete evacuation, (vi) the Bristol Stool Form Score (BSFS) rating, (vii) whether the stool was provided as a sample and (viii) whether the defecation occurred at the time of antibiotic usage.…”