A randomised, placebo-controlled investigation of 24 weeks administration of a multi strain probiotics mixture on gut microbiota diversity and faecal metabolome in healthy seniors

Aging has been associated with changed composition and function of the gut microbiota. Some studies show that probiotics influence GM by increasing potentially beneficial lactobacilli and bifidobacteria and inhibiting potential pathogens in older adults. Here we investigate effects of the multi-strain probiotic HOWARU Restore on GM composition and function in older adults.Ninety eight healthy adult volunteers aged above 74 years were enrolled in a randomised double-blinded intervention receiving HOWARU Restore or placebo daily for 24 weeks with 45 volunteers from each group completing it. Questionnaires to monitor effects on gastro-intestinal discomfort and bowel movements were collected. Faecal samples for GM characterisation and metabolomics were collected at baseline and after 24 weeks.In the probiotic group, self-reported gastro-intestinal discomfort in the form of flatulence was significantly decreased during the intervention. At baseline 151 core species were identified. The majority of core species belonged to the Lachnospiraceae and Ruminococcaceae families. Neither alpha diversity nor beta diversity measures were affected by probiotic intake. On the contrary we observed high intra individual GM stability with individual accounting for 72 to 75 percent of variation. Similarly, high intra individual stability and no marked effect of probiotic intake was observed in faecal metabolite profiles. In conclusion, 24 weeks of HOWARU Restore intake reduce gastrointestinal discomfort in the form of flatulence in healthy, older adults, without significantly influencing GM composition and activity.