Early Probiotic Research: Open-label Functional Intervention and Longitudinal Evaluation in Healthy Adults

Change from baseline in plasma metabolomic and proteomic markers, representing cellular metabolism and circulating protein levels. Reported as change in normalised relative abundance for each analyte. Continuous measure.

Self-administered web-based battery of seven tasks modelled on the UK Biobank cognitive assessments. Components and scoring: reaction time (mean response latency in milliseconds across matching trials; lower is better); numeric memory (longest digit span correctly recalled; higher is better); symbol-digit matching (number of correct substitutions in 60 seconds; higher is better); word-pair memory (number of pairs correctly recalled out of 6; higher is better); matrix reasoning (number of puzzles solved correctly out of 5; higher is better); Trail Making A and Trail Making B (time to complete the sequence in milliseconds; lower is better). Each component is reported independently.

Change from baseline on a study-specific sleep questionnaire covering six domains. Sleep duration: hours of sleep per 24 hours including naps, 0 to 16 in half-hour steps; higher indicates longer sleep. Sleep quality: 5-point ordinal scale (very poor, poor, average, good, very good); higher is better. Daytime sleepiness: 4-point ordinal scale (never, sometimes, often, always); higher is worse. Difficulty falling asleep and difficulty staying asleep, each a 4-point ordinal scale (no, occasionally, yes often, every night); higher is worse. Sleep-onset latency: 4 ordered categories (under 15 minutes, 15 to 30 minutes, 30 to 60 minutes, over 60 minutes); longer is worse. Causes of night-time waking: multi-select checklist of 8 options, reported descriptively as the proportion of participants endorsing each cause, not scored. Each domain is reported separately; no total score is used as an outcome measure.

Change from baseline in self-reported wellbeing, assessed by two single-item ratings collected at each study assessment. Mood: "How are you feeling today?", 5-point ordinal scale (very low, low, neutral, good, very good); higher is better. Stress: "Stress level today", 4-point ordinal scale (none, mild, moderate, high); higher is worse. Each item is analysed and reported separately; no composite score is derived.

Self-reported number of days on which the study supplement was taken during each consecutive 14-day period, recorded by participants at the end of each period. Integer count from 0 to 14 per period; higher indicates greater adherence. Reported as the count per period and as percentage adherence (days taken divided by 14, multiplied by 100).

Count of adverse events reported by participants, and the severity of each event graded as mild, moderate or severe. Reported as the number of participants with at least one adverse event, the total number of events, and the number of events at each severity grade. Higher counts indicate a less favourable tolerability profile.

Participant-rated acceptability of five study procedures, assessed once at the Week 4 end-of-intervention visit using a study-specific questionnaire. Each procedure is rated on a 5-point ordinal scale: 1 = not at all acceptable, 2 = slightly acceptable, 3 = moderately acceptable, 4 = very acceptable, 5 = completely acceptable. Higher scores indicate greater acceptability. Each item is reported separately; no total or composite score is derived. Three optional free-text questions are collected and reported descriptively. Feasibility is additionally assessed as recruitment rate (participants enrolled as a proportion of those screened, and mean enrolled per month across recruitment) and outcome completion (proportion of scheduled assessments and biological samples completed and usable, reported separately for stool samples, blood samples, cognitive batteries, and mood and stress ratings).