This 12-week, double-blind, placebo-controlled trial will examine whether daily supplementation with the Lab4P probiotic can improve cognitive performance and metabolic health in overweight adults aged 18 to 40 with impaired glucose tolerance, a preclinical condition where blood glucose regulation is mildly disrupted. Seventy participants will be randomly assigned to receive either Lab4P or a placebo. The study will assess changes in memory, executive function, and processing speed, along with blood glucose control, cardiovascular function, cholesterol levels, body composition, and markers of inflammation. The study will also analyse changes in the gut microbiome and evaluate the safety and tolerability of the probiotic.
Aged 18-40 years
Body Mass Index (BMI) between 25.0 and 29.9 kg/m² (classified as overweight)
In good general health (self-reported)
Normal self-reported sleep patterns, with no history of diagnosed sleep disorders
Diagnosed diabetes (any type).
Diagnosed sleep disorders.
Fasting glucose >6.9 mmol/L during screening.
History of bariatric surgery (e.g., gastric bypass, sleeve gastrectomy).
Parallel
Lab4p Probiotic Consortium
Dietary supplementThe investigational product in this study is Lab4P, a patented multi-strain probiotic consortium formulated as a food supplement and supplied in capsule form. Each daily dose contains a total of 5 × 10¹⁰ CFU of live bacteria, comprising five strains: Lactobacillus acidophilus CUL60 and CUL21, Lactobacillus plantarum CUL66, Bifidobacterium bifidum CUL20, and Bifidobacterium animalis subsp. lactis CUL34. In addition to probiotics, each capsule also contains three micronutrients at 100-200% of the recommended daily intake: Vitamin D (10 µg; 200%), Vitamin C (80 mg; 100%), and Zinc (10 mg; 100%). Lab4P is a marketed, human-approved product manufactured by Cultech Ltd. (Port Talbot, UK) and is classified as a food supplement, available for purchase without prescription. Both the active product and placebo will be identically packaged to maintain blinding.
Placebo
Other interventionPlacebo capsules are composed of microcrystalline cellulose, and are identical in appearance to the test product.
Verbal Memory Performance
Assessed using the Cambridge Neuropsychological Test Automated Battery (CANTAB) Verbal Recognition Memory task (VRM) a computerized word list recall task, which measures accuracy in recalling previously presented verbal stimuli to evaluate verbal memory function.
Visual Episodic Memory
Measured using the Paired Associates Learning (PAL) task (CANTAB), which assesses the ability to remember the locations of visual patterns and form new associations.
Number of Participants Reporting One or More Adverse Events (AEs) or Serious Adverse Events (SAEs)
All adverse events (AEs) and serious adverse events (SAEs) will be monitored through participant self-reports and case report forms. Events will be categorized by severity and relatedness to the study product.
Visuospatial Working Memory
Measured using the Spatial Working Memory (SWM) task (CANTAB), which assesses the ability to temporarily retain and manipulate spatial information and use effective search strategies during problem-solving.
Executive function (Response Inhibition and Impulse Control)
Measured using the Stop Signal Task (SST) (CANTAB), which assesses the ability to inhibit a dominant or preplanned motor response when signaled.
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Leeds Beckett University
Lead sponsor
Cultech Ltd, Port Talbot, UK
Collaborator
