None listed
Conditions
Brief summary
Objective: To determine whether 8-week administration of dietary prebiotic foods and/or probiotic supplements reduces symptoms of psychological distress in non-clinical adults with low mood and poor diet quality, relative to placebo. Secondary aims are to measure the relationship between treatment response and changes in cognition, well-being, health-related quality of life, sleep, and bowel health, and to determine whether treatment response is mediated by changes in gut microbiota. Hypotheses: It is hypothesised that both probiotic and prebiotic treatments will be superior to placebo, while the synbiotic treatment will potentially be superior to all others, in the reduction of psychological distress. It is also predicted that this pattern will remain consistent for measures of cognition, well-being, quality of life, bowel health and sleep. Finally, we hypothesise that treatment response will be mediated by changes in gut microbiota (showing lower levels of psychological distress versus higher levels of psychological distress in placebo). Design: An 8-week randomised controlled trial comparing the efficacy of a probiotic supplement versus a high-prebiotic diet versus a synbiotic treatment (probiotic + high-prebiotic diet) versus placebo in 128 healthy adults with poor mood and low dietary quality. The probiotic supplementation component will be double-blinded. Participants are community-dwelling adults aged 18-65 years who meet eligibility requirements for poor mood and low dietary quality.
Interventions
Group A (probiotic group; 8-week duration): Twice-daily oral capsule of Bioceuticals MoodBiotic, containing 8 probiotic strains delivering 12 billion colony forming units (CFUs) + no change to existing diet. Each oral capsule will contain the following probiotic strains:
Bifidobacterium bifidum (Bb-06): 2 billion colony forming units (CFU)
Bifidobacterium animalis subsp. lactis: 1 billion CFU
Bifidobacterium longum (Rosell-175): 1 billion CFU
Lactobacillus acidophilus (La-14): 2 billion CFU
Lact
Group A (probiotic group; 8-week duration): Twice-daily oral capsule of Bioceuticals MoodBiotic, containing 8 probiotic strains delivering 12 billion colony forming units (CFUs) + no change to existing diet. Each oral capsule will contain the following probiotic strains: Bifidobacterium bifidum (Bb-06): 2 billion colony forming units (CFU) Bifidobacterium animalis subsp. lactis: 1 billion CFU Bifidobacterium longum (Rosell-175): 1 billion CFU Lactobacillus acidophilus (La-14): 2 billion CFU Lactobacillus helveticus (Rosell-52): 2 billion CFU Lactobacillus casei (Lc-11): 2 billion CFU Lactobacillus plantarum (Lp-115): 1 billion CFU Lactobacillus rhamnosus (HN001): 1 billion CFU Group B (prebiotic group; 8-week duration): High-prebiotic diet + twice-daily oral placebo (inactive) capsule. Dietary intervention involves eating 7 or more serves of prebiotic-rich foods per day. Prebiotic-rich foods are plant foods containing relatively high levels of fructans and/or galactooligosaccharides, as reported in the food-science literature. Some examples are asparagus, garlic, onion, oats, whole wheat, chickpeas, and watermelon. The remainder of the diet is subject to the participant's discretion. An online educational video (8-minute duration), prepared and delivered by an Accredited Practising Dietitian/nutrition lecturer will be shown to participants at their baseline session and a hard-copy handout provided. Content of video/handout: information on the high-prebiotic diet, suitable foods and how to introduce them into the diet, and recipe suggestions. The video and handout were specifically designed for the current study. Participants are responsible for purchasing and incorporating high-prebiotic foods into their diet. A hamper of shelf-stable high-prebiotic foods will be provided to participants at baseline, as a 'starter kit'. Group C (synbiotic group; 8-week duration): Combination of Group A (twice-daily oral probiotic capsule) + Group B (high-prebiotic diet) interventions For all groups, supplement compliance will be measured by returned capsule count at 8-weeks. Adherence to allocated diet will be measured by completion of a purpose-built online dietary screener at Weeks 0, 2, 4, 6, and 8.
Sponsors
The University of Melbourne
Study design
Allocation
Randomised controlled trial
Intervention model
Factorial
Primary purpose
Treatment
Masking
Blinded (masking used) (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
All
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
- Prebiotic fibre intake of <3 grams/day, as measured by a purpose-built Dietary Screener, to ensure that there is sufficient scope for improvement in diet - Subclinical levels of anxiety and/or depression. Eligible participants must score 16-26 on the Kessler Psychological Distress Scale (K10) - Free of psychiatric medications for > 4 weeks
Exclusion criteria
- Ingestion of fermented foods or probiotic supplements within past 2 weeks - Substance dependence within the previous month - BMI over 35 - Fulfils diagnostic criteria for a clinical mental illness - Currently taking medication with primarily CNS activity - Pregnancy - Irritable bowel syndrome or chronic constipation, and FODMAP-sensitive individuals - Taking antibiotics, proton pump inhibitors, non-steroid anti-inflammatory drugs (any amount greater than 3 doses per month), or immunocompromising medication
Outcome results
None listed