PRECOG Pilot Project

The Impact of Chronic Consumption of Plant-based Fibres on Cognitive Performance, Gut Microbiome and Mental Health Outcomes in Older Adults: a Pilot Randomised Controlled Trial

This pilot study aims to investigate the chronic effects of a prebiotic blend on cognitive, affective and gut microbiome outcomes in healthy adults aged 60-75 years.

This pilot study will employ a double-blind, randomised, placebo-controlled parallel design to investigate the chronic effects of 12-week-long prebiotic blend consumption on cognitive, affective, gut microbiome, metabolic, and anthropometric outcomes in healthy older adults with mild to moderate subjective cognitive complaints. Fifty participants will be randomised to Intervention or Placebo groups where they will be consuming 10g of prebiotic fibre blend or 10g of placebo (matched placebo powder) per day for 12-weeks. Outcome measures will be acquired before and after a 12-week chronic supplementation. These will include cognitive measures of overall cognitive functioning, and domain-specific cognitive performance, affective measures of depression and anxiety symptomatology; gastrointestinal symptomatology; systolic and diastolic blood pressure, as well as height, weight, hip and waist circumference. In addition, stool samples will be collected at all timepoints to assess microbiome diversity and composition.

Inclusion Criteria:

• Aging between 60-75 years old
• Having normal vision and hearing
• Having a normal body mass index (BMI<30)

Exclusion Criteria:

• Having mild to moderate subjective cognitive complaints
• Smoking
• Having food allergies
• Following restrictive and/or unbalanced diets
• Changing dietary intake majorly in past month
• Being diagnosed with any psychiatric or neurologic conditions (e.g. schizophrenia, depression, dementia) including eating disorders
• Being diagnosed with any cardiometabolic diseases (including type II diabetes and cardiovascular disease), or suffering from hypertension or thrombosis related disorders or suffer from thyroid disease
• Currently taking anticoagulants, antiplatelet medication, antidepressants, proton-pump inhibitors
• Currently consuming prebiotic or probiotic supplements
• Continuous antibiotic use for > 3 days within 1 month prior to enrolment
• Continuous use of weight-loss drug for > 1 month before screening
• Having a significant gastrointestinal (GI) condition affecting absorption including (but not limited to) inflammatory bowel disease; total colectomy or bariatric surgery; irritable bowel disease; end stage renal disease; active cancer, or treatment for any cancer, in last 3 years
• Having a high fibre intake defined as > 20g of fibre/day
• Wheat and/or gluten intolerance and having coeliac disease