Jens Walter’s research while affiliated with University College Cork and other places

Probiotic supplements containing high β-galactosidase-producing bacteria may aid in the management of lactose intolerance. We previously isolated a strain of Bifidobacterium adolescentis , iVS-1, from the fecal sample of a human donor after consumption of galactooligosaccharides (GOS), a prebiotic derived from lactose. Therefore, it was hypothesized that iVS-1 might reduce symptoms associated with lactose maldigestion. Compared to other probiotic strains, iVS-1 had high β-galactosidase activity and reduced gas formation by fecal communities during in vitro fermentations of lactose or milk. A randomized placebo-controlled clinical trial was then conducted with 21 lactose maldigesters, randomized to receive either B. adolescentis iVS-1 (n = 11) or placebo (n = 10) daily for two weeks. Compared to the two-week run-in period, iVS-1 abundance was higher at the end of the treatment period (p = 0.0005) and after the two week post-treatment period (p = 0.045). The iVS-1 group experienced less overall daily symptoms during the treatment period when compared to placebo (p = 0.032) and had significant improvement for fecal urgency (p = 0.033) and diarrhea (p = 0.006). The metabolism of lactose, reduction of gas, and improvement of multiple gastrointestinal symptoms suggests B. adolescentis iVS-1 may be an effective treatment for lactose intolerance. Trial Registration The trial is registered at ClinicalTrials.gov ( https://clinicaltrials.gov/study/NCT05668468 ).

Microbiomes provide key contributions to health and potentially important therapeutic targets. Conceived nearly 30 years ago, the prebiotic concept posits that targeted modulation of host microbial communities through the provision of selectively utilized growth substrates provides an effective approach to improving health. Although the basic tenets of this concept remain the same, it is timely to address certain challenges pertaining to prebiotics, including establishing that prebiotic-induced microbiota modulation causes the health outcome, determining which members within a complex microbial community directly utilize specific substrates in vivo and when those microbial effects sufficiently satisfy selectivity requirements, and clarification of the scientific principles on which the term 'prebiotic' is predicated to inspire proper use. In this Expert Recommendation, we provide a framework for the classification of compounds as prebiotics. We discuss ecological principles by which substrates modulate microbiomes and methodologies useful for characterizing such changes. We then propose statistical approaches that can be used to establish causal links between selective effects on the microbiome and health effects on the host, which can help address existing challenges. We use this information to provide the minimum criteria needed to classify compounds as prebiotics. Furthermore, communications to consumers and regulatory approaches to prebiotics worldwide are discussed.