Mediterranean-style Dietary Pattern (MDP), Mood and Anxiety

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.

Inclusion criteria

• Male and female, aged 18 or above
• Is willing and able to comply with all study procedures, including changes in diets
• Has access to and able to use the internet/computer/tablet device
• Mild to moderate level of anxiety and/or depression symptoms, assessed by Generalised Anxiety disorder (GAD-7) score and Patient Health Questionnaire (PHQ-9), scores 5 to 14 on both questionnaires
• A habitual MEDAS score of ≤ 7/14
• To be fluent in English

Exclusion criteria

• MEDAS score >7
• Vegan/vegetarian
• Allergies to one of the study components i.e. nuts, fish
• On antidepressant or antianxiety medication where dosage is likely to change over the next 3 month
• Factors precluding MRI scanning such as suffers from claustrophobia or has metal implants
• Not fluent in English
• Not agreement for the study team to contact the participants general practitioner about trial participation and screening results
• Not prepared to make changes to the diet for 10 days (2 x 5 day periods)