The objective of this study is to investigate the efficacy of a culturally-adapted Mediterranean diet, in accordance with clinical guidelines and research evidence, in reducing depressive symptoms among Hong Kong Chinese adults. Additionally, this study will also explore the potential underlying role of the gut microbiome in the relationship between the Mediterranean diet and depression. This study serves as a pioneering attempt to examine the efficacy and intervention acceptability of a culturally-adapted Mediterranean diet in managing depressive symptoms. Several studies have demonstrated the relationship between diet and mood, while existing studies suggest that consistently adhering to the Mediterranean diet may yield a more pronounced antidepressant effect. Considering that depression is often associated with low motivation, dietary interventions that require active participation may encounter implementation challenges and potentially impact the adherence rate. To address this issue, our study proposes using ecological momentary assessment (EMA), which involves sending frequent reminders to participants, allowing us to examine diet quality and adherence as well as changes in depressive symptoms at various time points. This approach also minimizes potential recall bias and enhances data collection accuracy. If the hypothesis is supported, dietary intervention could emerge as a promising therapeutic strategy for alleviating depressive symptoms. Furthermore, this study could provide insights into the role of the gut microbiome as a potential underlying mechanism between diet and depressive symptoms. The findings could have significant implications for clinical practice.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
90
This group will adhere to the meals (meal delivery, excluding weekends and holidays) prepared by the research team and report their mood and diet quality and adherence using EMA with push notifications four times a day. In addition, photographic food records will also be used to record planned or unplanned meals or snacks. Pre-recorded sessions covering topics such as general dietetic advice, nutrition education on the Mediterranean diet and food components, SMART goal setting will be provided to the participants before the initiation of the MediDiet intervention. Moreover, a brief weekly phone call will be conducted to assess participant adherence, provide encouragement, and address any issues or challenges that may arise.
The Chinese University of Hong Kong
Shatin, Hong Kong
Change in the Patient Health Questionnaire-9 (PHQ-9)
The PHQ-9 is a 9-item questionnaire used for screening, diagnosing, monitoring and measuring the severity of depression, which scores each of the nine DSM-IV criteria from "0" (not at all) to "3" (nearly every day).
Time frame: Baseline, immediate post-intervention, and 12-week follow-up
Change in the Generalized Anxiety Disorder 7-item Scale (GAD-7)
The GAD-7, a 7-item self-report questionnaire, was used to measure generalized anxiety symptoms. Each item is rated on a 4-point Likert scale, with response categories ranging from 'not at all' (0) to 'nearly every day' (3). The total score is the sum of the 7 items, with a range of 0 to 21.
Time frame: Baseline, immediate post-intervention, and 12-week follow-up
Change in the Insomnia Severity Index (ISI)
The ISI is a 7-item scale designed to evaluate perceived insomnia severity. Ratings on the 5-point Likert scale are obtained on the perceived severity of sleep-onset, sleep-maintenance, early morning awakening problems, satisfaction with current sleep pattern, interference with daily functioning, noticeable of impairment attributed to the sleep problem, and level of distress caused by the sleep problem.
Time frame: Baseline, immediate post-intervention, and 12-week follow-up
Change in the adapted version of the Modified Mediterranean Diet Score (ModiMedDiet Score)
The ModiMedDiet Score is a 12-item criterion-based diet quality index ranging from 0-120, with higher scores indicating greater adherence to the Mediterranean diet pattern promoted in the SMILES dietary intervention trial. It assesses intake of 12 food groups based on recommended intakes. Scores were calculated for both intervention and control groups to measure compliance and dietary changes over time. An adherence level of ≥55.62 was defined as highest, and ≤33.65 as lowest. Extras intake (sweets, processed foods, fast food, sugary drinks) was also reported separately due to their less healthy profiles. An adapted version will be designed based on the original ModiMedDiet to reflect the food groups delivered to the MediDiet group in the current study.
Time frame: Baseline, immediate post-intervention, and 12-week follow-up
Change in the Seven-day Food Record (7dFR)
The 7dFR is a self-reported record of all foods and beverages consumed over a consecutive 7-day period. Participants record descriptions of food/drink items, amounts consumed, brands, preparation methods and portion sizes for every eating occasion over the 7 days. Intakes are then analyzed using nutrition software to derive daily nutrient intakes.
Time frame: Baseline, immediate post-intervention, and 12-week follow-up
Change in the International Physical Activities Questionnaire-Chinese version (IPAQ-C)
The IPAQ-C is a 5-item self-report tool that measures time spent sitting, walking, in moderate activity, and vigorous exercise in the last 7 days. Responses are converted to minutes and reported as a continuous metabolic equivalent task (MET) minutes per week variable, with the exception of sitting time reported in hours. MET is a quantitative indicator of energy expenditure, with walking assigned 3.3 METs, moderate activity 4 METs, and vigorous activity 8 METs. A total physical activity score is calculated as the sum of walking and moderate to vigorous exercise MET-minutes. Higher total scores represent greater physical activity levels.
Time frame: Baseline, immediate post-intervention, and 12-week follow-up
Change in the Short Form (Six-Dimension) Health Survey (SF-6D)
HRQoL will be evaluated using the Short Form (Six-Dimension) Health Survey (SF-6D; Lam et al., 2008). The participants select the levels (up to 4 or 6 levels) that best describe their physical functioning, role limitation, social functioning, bodily pain, mental health, and vitality. A preference-based single index measure is calculated by adding the scores of the 6 dimensions using a scoring algorithm. The total SF-6D score ranges from 0.315 (the worst HRQoL) to 1 (full health).
Time frame: Baseline, immediate post-intervention, and 12-week follow-up
Change in the Sheehan Disability Scale (SDS)
SDS is a brief, 5-item self-report tool that assesses functional impairment in work/school, social life, and family life.
Time frame: Baseline, immediate post-intervention, and 12-week follow-up
Change in the Treatment Acceptability Scale (TAS)
TAS is a 15-item self-report measure used to assess parents' and caregivers' acceptability and willingness to implement a proposed treatment for their child. Respondents rate their level of agreement with statements about the treatment on a 7-point Likert scale ranging from 1 (strongly disagree) to 7 (strongly agree). Example items address the treatment's effectiveness, appropriateness, risks, and consent requirements. Scores are summed with higher total scores indicating greater treatment acceptability. The TAS provides a standardized tool for clinicians to evaluate parents' perceptions of interventions as part of the treatment selection process.
Time frame: Baseline and immediate post-intervention
Change in the Credibility-Expectancy Questionnaire (CEQ)
The 6-item CEQ yielded ratings of treatment credibility, acceptability/satisfaction, and expectations for success.
Time frame: Baseline and immediate post-intervention
Change in gut microbiome
Fresh stool samples will be collected by participants using the gut microbiome test kit developed by BioMed Technology, Hong Kong.
Time frame: Baseline and immediate post-intervention
Self-developed Survey
The self-developed survey will collect basic demographic information such as age, gender, level of education, occupation, relationship status, height, weight, waist circumference, and body mass index (BMI).
Time frame: Baseline
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