The disaccharide and innovative ingredient cellobiose, consisting of two β-glucose molecules linked by a β(1→4) bond is the main component of cellulose. Cellobiose can be used within a wide variety of foodstuffs and functional foods as a low-caloric bulking agent or as a substitute for lactose. For purposes of industrial large-scale production, cellobiose is produced by an enzymatic reaction in which sucrose and glucose are converted to cellobiose and fructose. The goal of this single-arm, dose-escalation study was to evaluate the safety and tolerability of cellobiose and to determine the maximum tolerated dose of cellobiose in healthy subjects. Following a baseline period, consecutive cohorts of six subjects each consumed either single doses of 10, 15, 20 and 25 g, while 12 subjects each received multiple doses of 15 g or 20 g cellobiose (twice daily, 14 days). The main recorded parameters were stool consistency, gastrointestinal well-being (Gastrointestinal Symptom Rating Scale) and adverse events. In each highest single/multiple dosage group, some sensitive subjects experienced flatulence, borborygmus and/or transient diarrhoea. A 100% global tolerability rating makes 20 g cellobiose a tolerable dose for single use. For repeated consumption, we propose up to 15 g cellobiose twice daily (92.6% global tolerability rating). Cellobiose is a promising new ingredient with excellent tolerability.

The gut–brain axis plays a pivotal role in mental health, with synbiotic supplements emerging as promising interventions for stress and anxiety management. This observational open-label pilot study aims to evaluate the effects of a symbiotic supplement containing Bacillus subtilis DSM 32315 and L-alanyl-L-glutamine, delivered via a targeted colonic-release capsule, on stress, anxiety, and mental wellbeing. Conducted as a non-placebo-controlled real-world case study, the study recruited 100 adults with elevated perceived stress and followed them for over eight weeks. Validated self-reporting tools, including the Depression Anxiety Stress Scales-21 items (DASS-21), Perceived Stress Scale-10 items (PSS-10), Athens Insomnia Scale (AIS), Short Form Health Survey-12 items, and Gastrointestinal Symptom Rating Scale questionnaires, were used to assess outcomes. Statistical analyses, primarily using linear mixed models, indicated reductions in DASS-21, PSS-10, and AIS scores, along with self-reported improvements in gastrointestinal symptoms and mental well-being. These findings should be interpreted cautiously due to the exploratory, uncontrolled study design. Notably, DASS-21 total scores declined within one week, with reported benefits sustained at four and eight weeks. However, these rapid changes may partly reflect expectancy effects or regression to the mean. These observations provide valuable insights for further hypothesis generation, notably that the synbiotic supplement could support stress management and mental health by modulating the gut–brain axis. However, further placebo-controlled trials including measurement of relevant biomarkers are warranted to confirm these observations and explore underlying mechanisms.