Investigating the Acute and Chronic Effects of a Supplement Containing Caffeine, Vitamins, Minerals and Botanical Extracts on Cognition, Sleep and Wellbeing, in Healthy Volunteers

The study will follow a randomised, placebo-controlled, double-blind, crossover design. Participants will first receive either the active treatment (a blend containing 120mg caffeine, vitamins, minerals and botanical extracts) or a matched placebo (containing 17mg Marigold extract and brown rice flour), for 29 days before crossing over to the other treatment condition for a further 29 days. Participants will attend all 6 appointments required, 5 of which will be at the research centre, will complete at home treatment diary daily, as well as completing the at home assessments.

Participants will initially attend a virtual screening appointment (conducted via telephone call or Microsoft Teams) which will involve obtaining informed consent, health screening, completion of the Caffeine Consumption Questionnaire (CCQ) and collection of demographic information. Participants will then attend the research centre on five occasions.

The first laboratory appointment will be an introductory training session which will comprise of collection of physiological eligibility measures (height, weight, waist-to-hip ratio, blood pressure) and training on the cognitive tasks, and sleep and wellbeing measures. Following this, the four testing visit appointments will be identical in procedure with the exception of the treatment administered.

For testing visits, participants will attend the research centre having abstained from alcohol (24 hours), over-the-counter medications (24 hours) and antihistamines (48 hours). There will be minimal restrictions to the participant in terms of abstinence from caffeine or food prior to testing visits; participants will be encouraged to follow their normal routine in regard to breakfast and caffeine consumption (whereby participants eat or do not eat breakfast based on what is usual for them). Participants must however consume their usual breakfast and caffeine no later than 1 hour prior to arrival and should ensure their breakfast and caffeine consumption is consistent across all 4 testing visits. Upon arrival, physiological measures will be collected including height and weight, blood pressure and waist-to-hip ratio. Participants will then complete a series of mood, wellbeing and sleep questionnaires including Visual Analogue Mood Scales (VAMS); Positive and Negative Affect Scale (PANAS); State Trait Anxiety Inventory (STAI); Depression, Anxiety and Stress Scale (DASS-21); Core Consensus Sleep Diary (CSD- Core); Sleep Quality Scale (SQS); World Health Organisation Quality of Life Questionnaire (WHOQOL-BREF). At testing visit 2 and 4 (Day 29 chronic visit, for each study arm) participants will complete the Caffeine Consumption Questionnaire to monitor changes to caffeine intake.

Following this, participants will complete a 50-minute computerised cognitive assessment administered via COMPASS including word, picture and face recognition, immediate word recall, delayed word recall, numeric working memory, choice reaction time, corsi blocks, peg and ball and cognitive demand battery (3 repetitions of serial 3 subtractions, serial 7 subtractions, rapid visual information processing task (RVIP) and 'mental fatigue' visual analogue scales).

After the COMPASS assessment, participants will consume their randomly allocated treatment for the day and a further blood pressure reading will be collected. An identical COMPASS assessment will be completed at 30 minutes post-dose. Following completion of the second COMPASS assessment, participants will be provided with their treatment to consume daily at home for the 29-day supplementation period. Participants will receive treatment consumption instructions and a treatment diary to write down the time treatment is taken each day. Participants will be instructed to return the completed treatment diary and all unused treatment at the following testing visit appointment (following the supplementation period).

For each study arm (each 29-day supplementation period) there will be 3 at home assessments for participants to complete via Qualtrics and Cognimapp. These will be a short series of sleep and wellbeing questionnaires, and a short battery of cognitive tasks, including VAMS, PANAS, SQS and Numeric Working Memory, Choice Reaction Time and Peg and Ball.

Inclusion criteria

• You self-assess yourself as being in good health.
• You are aged 18-75 years at the time of giving consent.
• English is your first language or are fluent in English.

Exclusion criteria

• Insufficient (< 40 mg per day) or excessive (> 500 mg per day) habitual caffeine consumption (* NOTE: This will be calculated at screening but feel free to query this with the researcher prior to attendance.).
• Have any pre-existing medical conditions/illnesses which will impact taking part in the study. (* NOTE: The explicit exceptions to this are controlled hyper/hypothyroidism, hay fever, high cholesterol and reflux-related conditions. NOTE: There may be other, unforeseen, exceptions and these will be considered on a case-by-case basis, i.e. participants may be allowed to progress to screening if they have a condition/illness which would not interact with the active treatments or impede performance so it's worth discussing any medical conditions with the researcher prior to booking lab appointments).
• Are currently taking prescription medications which will impact taking part in the study (* NOTE: the explicit exceptions to this are contraceptive treatments for female participants, thyroid medications, topical skin treatments and those medications used in the treatment of high cholesterol and reflux-related conditions; and those taken 'as needed' in the treatment of asthma and hay fever.).
• Have high blood pressure (systolic over 139 mm Hg or diastolic over 89 mm Hg1) - *NOTE: We must measure this in the lab using our blood pressure monitors and can only use our measurements to access eligibility rather than home or GP readings.
• Have a Body Mass Index (BMI) outside of the range 18.5-39.9 kg/m2.
• Are pregnant, seeking to become pregnant or lactating.
• Have been diagnosed with a neurological condition or assessed as having a learning/behavioural or neurodevelopmental difference (e.g. dyslexia, autism, ADHD).
• Have a visual impairment that cannot be corrected with glasses or contact lenses (including colour-blindness).
• Smoke tobacco/ vape nicotine/ use nicotine replacement products (* NOTE: If participants have recently quit smoking or using replacements, they must have stopped using them altogether for a period of 3 months before participating in this study).
• Have relevant food allergies/ intolerances/ sensitivities (Please discuss all allergies/ intolerances/ sensitivities with the researcher prior to your screening appointment).
• Have taken antibiotics within the past 4 weeks.
• Are currently consuming any other dietary supplement (e.g., vitamins, omega 3 fish oils etc.) or have done so in the last 4 weeks. (* NOTE: Participation is possible following a 4-week supplement wash out prior to participating and for the duration of the study on the proviso that the supplements they are taking are out of choice and not medically prescribed or advised. Please discuss with the researcher if unsure. NOTE: We would never advise stopping supplements prescribed by your doctor e.g., iron, calcium etc., only those you use out of choice).
• Have any health conditions that would prevent the fulfilment of the study requirements (this includes non-diagnosed conditions for which no medication may be taken).
• Are unable to complete all of the study assessments (this will be assessed by the researcher at your training appointment, whereby you must be able to reach the minimum scores for each cognitive task to progress with the trial).
• Are currently participating in another clinical or nutrition intervention study or have done so in the past 4 weeks.
• Have been diagnosed with/ undergoing treatment for alcohol or drug abuse in the last 12 months.
• Have been diagnosed with/ undergoing treatment for a psychiatric disorder in the last 12 months, including a medical diagnosis of anxiety or depression.
• Suffer from frequent migraines that require medication (more than or equal to 1 per month).
• Have any sleep disorders or take any sleep aid medications.
• Have any known active infections.
• Will be non-compliant with regards to treatment consumption.
• Does not have a bank account (required for payment).