Observational studies and a limited numbers of RCTs have observed that habitual Mediterranean-style dietary pattern (MDP) consumption is associated with improved mental health and cognition. Yet, its efficacy in a short-term has not been studied in well-controlled intervention settings. MediMood is a cross-over RCT aiming to test whether a MDP can affect mood and anxiety following a meal (postprandial) and over 5-days in adults over 18 years with mild to moderate mental health problems relative to a Western diet (WD).
Depression, anxiety and age-related cognitive decline are leading global public health problems. A plant-based Mediterranean-style dietary pattern (MDP) includes olive oil as the main source of fat, fresh fruits, vegetables, seafood, legumes and nuts and a low consumption of red and processed meat, confectionary, and high-sugar drinks. A MDP promotes both physical and mental wellbeing and brain function. However, most studies to date have examined the impact of a MDP on health over months or years. As several underpinning biological mechanisms are likely to be responsive within hours or days, examining the short-term effect of a MDP on mental health outcomes is important. The overall goal of the present study is to understand the effects of a MDP on acute/sub-chronic brain health and its underpinning mechanisms. MediMood is a randomised cross-over efficacy trial. Participants will be assigned to an isocaloric MDP and a Western diet (WD) for 5-days in a random order with a 4-week wash-out period. All foods, meal plans and detailed dietary instructions will be provided. In addition to the primary outcome measures (mood and anxiety), the impact of intervention on cognitive performance, sleep, cerebral blood flow (MRI) and a selection of biomarkers of brain function will be measured in biological samples over five days. As low mood, anxiety and stress disorders affect daily functioning and reduce the quality of life significantly for many, the investigators believe the findings will have wide public health application.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
SINGLE
Enrollment
25
All foods, meal plans and instructions provided.
All foods, meal plans and instructions provided.
University of East Anglia
Norwich, Norfolk, United Kingdom
Change in mood
Established by the Bond-Lader visual analogue scale (includes 16 items each having antonyms on two ends, on a scale of 1 to 100, 50 being the neutral point)
Time frame: Baseline (morning of day 1), Postprandial (after lunch on Established by the Bond-Lader visual analogue scale (includes 16 items each having day 1), 24-hours (morning of day 2), day 5 (morning of day 6 upon completion of 5 full days intervention)
Change in anxiety
Established by the Profile of Mood States (includes 65 items on a 5 point Likert scale)
Time frame: Baseline (morning of day 1), Postprandial (after lunch on day 1), 24-hours (morning of day 2), day 5 (morning of day 6 upon completion of 5 full days intervention)
Change in cognitive performance
Established by a neuropsychological test battery (https://neuropsychology.online) which assesses the following measures; attention, motor function, executive function, episodic memory, impulse control, visuospatial function
Time frame: Baseline (morning of day 1), Postprandial (after lunch on day 1), day 5 (morning of day 6 upon completion of 5 full days intervention)
Cerebral blood flow
Measured using MRI
Time frame: Postprandial day 1
Change in blood pressure
Measurements of brachial artery blood pressure (both diastolic and systolic pressure)
Time frame: Baseline (morning of day 1), Postprandial (after lunch on day 1), day 5 (morning of day 6 upon completion of 5 full days intervention)
Change in gut microbiota speciation
Faecal samples will be analysed for the gut microflora using 16sRNA sequencing.
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Time frame: Baseline (morning of day 1), day 5 (morning of day 6 upon completion of 5 full days intervention)
Change in plasma short chain fatty acids (SCFA)
Acetate, propionate and butyrate
Time frame: Baseline (morning of day 1), Postprandial (after lunch on day 1), day 5 (morning of day 6 upon completion of 5 full days intervention)
Change in untargeted metabolomics
Analysed through faecal samples using 1H-NMR-based untargeted metabolomics approach.
Time frame: Baseline (morning of day 1), Postprandial (after lunch on day 1), day 5 (morning of day 6 upon completion of 5 full days intervention)
Habitual sleep quality profile assessed by the Pittsburgh Sleep Quality Index
The Pittsburgh Sleep Quality Index is a 10-items validated questionnaire, which is based on 'the last month'. It will be used to establish usual sleep habits (before the interventions) and to identify sleep disturbances if there is any.
Time frame: Baseline (morning of day 1)
Change in subjective sleep quantity
Assessed using the Karolinska Sleep Diary (KSD). The KSD is a series of questions, with 5 possible tick box options, which characterise the efficiency and the duration of last night's sleep.
Time frame: Each morning, days 1-6
Change in subjective sleep quality
Assessed using the Karolinska Sleepiness Scale (KSS). The KSS is a single item, 9-point scale, assessing the sleepiness level at a particular time of day.
Time frame: Each morning, days 1-6
Change in objective sleep quality
Assessed using the MotionWatch 8. The MotionWatch 8 is a medical-grade actigraphy watch which can be used to monitor sleep, circadian rhythm and physical activity. Its software (The Motion Ware) will provide two objective measures of sleep quality, namely sleep efficiency and sleep fragmentation.
Time frame: Each morning, days 1-6
Participants subjective overview of the intervention
Assessed through a non-validated single question
Time frame: Upon completion of 5 full days