Examining the Effects of One-Month Probiotic Treatment on Mental Fatigue

The aim of this study is to demonstrate the effects of 28-days supplementation with a novel probiotic formulation on mental fatigue following a cognitive load in healthy adults. Half of the participants will receive the probiotic formulation while the other half will receive placebo.

A total of 128 participants will be recruited to take part in this trial.

The supplement contains selected strains of lactobacilli and bifidobacteria which have been well studied in human clinical trials. Previous clinical trials have demonstrated improvements in cognitive function and mood after supplementation with various combinations of lactobacilli and bifidobacteria.

The specific strains present in the current investigation have been studied in a number of clinical trials in which no adverse events were linked to the strains. The benefits of probiotic supplements on health is well established, and has led to an increase in use, as well as the addition of probiotic strains in dietary supplements. Despite this, only a small number of controlled trials have directly investigated the cognitive benefits associated with probiotic supplementation.

The current study therefore aims to investigate the anti-fatigue effects of a probiotic supplement after a period of cognitive demand. We will be measuring the effects of the probiotic supplement compared to a placebo using assessments of mental fatigue, cognition, memory and mood.

Eligibility Criteria:
Inclusion Criteria:

1. Male or female, aged 18-50 years, inclusive.
2. Willing and able to provide written informed consent.
3. Ability of the participant (in the Principal Investigator's opinion) to comprehend the full nature and purpose of the study including possible risks and side effects.
4. Agreement to comply with the protocol and study restrictions.
5. Available for all study visits.
6. Females of child-bearing potential required to provide a negative urine pregnancy test and be using effective contraception (e.g. surgically sterilized (tubal ligation or hysterectomy or partner is post-vasectomy, with sterility confirmed) or use an IUD (intrauterine device), a diaphragm or condom combined with contraceptive sponge, foam or jelly, or be using an oral contraceptive (the pill) for at least 2 cycles before the Screening-visit (Visit 0)).
7. Fluent in written and spoken English.
8. In good general health as judged by the Investigator/Clinical advisor based on medical history.
9. Must have normal, or corrected to normal vision.
10. Body mass index between 18.5 and 29.9kg/m2 (inclusive).
11. Participant is willing to maintain habitual diet (including caffeine and alcohol) and physical activity patterns throughout the study period.
12. Participant is willing and able to comfortably abstain from caffeine for 10 hours prior to and throughout the test visits, (2-3 hours).
13. Participant is willing to abstain from alcohol for 12 hours and vigorous physical activity for 12 hours prior to all study visits.

Exclusion Criteria:

1. History of dementia, stroke and other neurological conditions.
2. Traumatic loss of consciousness in the last 12 months.
3. History of epilepsy or Parkinson's disease.
4. Formal diagnosis of anxiety, depression or any psychiatric disorder that the Principal Investigator believes would interfere with the objectives of the study and requiring treatment (prescription of antidepressant, antipsychotic or other long term medication and/or referral for long term psychotherapy) in the last 2 years. Brief interventions for normal life events such as exam anxiety or bereavement are not an exclusion.
5. Have a significant acute or chronic coexisting illness (cardiovascular, gastrointestinal (irritable bowel syndrome (IBS), inflammatory bowel disease (IBD)), immunological, metabolic (including diabetes or cardiovascular disease), endocrine or bleeding disorders, neurodevelopmental or any condition which contraindicates, in the Principal Investigator's judgement, entry to the study.
6. Uncontrolled hypertension (systolic blood pressure \> 160mm Hg or diastolic blood pressure \>100 mm Hg).
7. Currently taking (from day of screening onwards) or have previously taken (last 4 weeks prior to screening) psychoactive medication (anxiolytics, sedatives, hypnotics, anti-psychotics, anti-depressants, anti-convulsants, centrally acting corticosteroids, opioid pain relievers).
8. Currently taking (from day of screening onwards) medication that the Principal Investigator believes would interfere with the objectives of the study, pose a safety risk or confound the interpretation of the study results such as:

   * high dose anticoagulant medication such as warfarin, heparin, clopidogrel, dabigatran, ticagrelor
   * non-steroidal anti-inflammatory drugs (NSAIDS; excluded only for daily use)
   * over-the-counter sleep medication (not categorized as sedatives, hypnotics or anti-depressants)
   * anti-cholinergic drugs or acetylcholinesterase inhibitors: bethanechol (Urecholine), donepezil (Aricept), rivastigmine (Exelon), galantamine (Reminyl), neostigmine (Prostigmin)
   * anti-histamines that cause drowsiness (eg. Ranitidine)
   * pseudoephedrine and phenylephrine
9. Currently taking (from day of screening onwards) dietary supplements that the Principal Investigator believes would interfere with the objectives of the study, pose a safety risk or confound the interpretation of the study results such as: melatonin, vitamin E, multivitamins, B vitamin complex, ginkgo biloba, fish oil, St. John's Wort or other cognitive enhancing dietary or herbal supplements over the study period.
10. Recent (within last 4 weeks prior to screening) or ongoing antibiotic therapy during the intervention period.
11. Daily consumption of concentrated sources of probiotics and/or prebiotics within 2 weeks of screening and throughout the intervention period other than the provided study products (e.g., probiotic/prebiotic tablets, capsules, drops or powders or yoghurts/yoghurt drinks containing probiotics).
12. Pregnant or lactating female, or pregnancy planned during intervention period.
13. Have self-reported dyslexia.
14. Current misuse of alcohol, drugs, or prescription medication.
15. Current smoker.
16. Self-declared illicit drug users (including cannabis and cocaine) for 3 weeks prior to screening and during the intervention period.
17. Excessive alcohol consumption (drinking on 5 or more days a week) for 3 weeks prior to screening and during the intervention period.
18. Contraindication to any substance in the investigational product.
19. Participation in another study with any investigational product within 30 days of screening and during the intervention period.
20. Investigator believes that the participant may be uncooperative and/or noncompliant and should therefore not participate in the study.
21. Participant under administrative or legal supervision.