The aim of this study is to investigate the effects of snack foods on mental health and the gut-brain axis, in adults with mild to moderate symptoms of depression and anxiety.
There is increasing evidence on the potential modulating role of healthy dietary patterns in managing symptoms of psychological distress including but not limited to depression and anxiety. Despite growing evidence, further research is required to investigate how dietary interventions may impact symptoms of depression and anxiety, as well as their mechanisms of action via the gut-brain axis. Consumption of snacks now contributes to roughly 17% and 21% of daily energy intake for men and women respectively. Therefore, snacks greatly impact nutritional intake and diet quality and can be a target of dietary manipulation for potential health benefits. This will be the first randomised controlled trial to assess the impact of snack consumption on mental health in adults with mild to moderate symptoms of depression and anxiety. The trial will use a parallel design with a 12-week intervention. Stool and blood samples will be collected at the beginning and end of the intervention for measurement of the gut microbiota and biomarkers related to the gut-brain axis.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
84
The intervention snack will be consumed by 42 participants for 12-weeks. Snacks will be consumed twice a day (mid-morning and mid afternoon snack).
The control snack will be consumed by 42 participants for 12-weeks. Snacks will be consumed twice a day (mid-morning and mid afternoon snack).
Metabolic research unit, Franklin-Wilkins Building, 150 stamford street
London, United Kingdom
Symptoms of depression and anxiety
Symptoms of depression and anxiety as measured by the Patient Health Questionnaire Anxiety and Depression Scale (PHQ-ADS). This is a 15-item self-report likert scale comprising the PHQ-8 and GAD-7. Scores can range from 0 to 48, cut points of 10,20 and 30 indicate mild, moderate and severe levels of depression/anxiety respectively.
Time frame: Week 0 and 12
Functional impairment
The self-report Work and social adjustment scale (WSAS) will be used to measure functional impairment scores. This is a self-report likert scale with 5 questions. Responses range from Not at all (0) to Very severely (8). 0-9, 10-19 and 20-40 represent low, moderate and severe impairment respectively.
Time frame: Weeks 0,6 and 12
Sleep quality
The self-report Pittsburgh sleep quality index (PSQI) will be used to measure sleep quality. This is a 19-item questionnaire with seven subcategories; subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction.
Time frame: Weeks 0,6 and 12
Wellbeing
The self-report world health organisation five well-being index (WHO-5) will be used to measure wellbeing. The scale consists of 5 items rated from All of the time (5) to At no time (0).
Time frame: Weeks 0,6 and 12
Quality of life
The self-report World Health Organisation Quality of Life Brief (WHOQOL-BREF) scale will be used to measure quality of life. This is a 26-item scale. Responses are rated on a 1-5 likert scale with 1 representing 'not at all' and 5 representing 'completely agree'. Scores are tabulated and multiplied by 4 to represent a score out of 100.
Time frame: Weeks 0,6 and 12
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Physical activity
The self-report international Physical Activity Questionnaire - Short form (IPAQ) will be used to measure physical activity.
Time frame: Weeks 0,6 and 12
Symptoms of depression
The self-report Patient Health Questionnaire-8 (PHQ-8) will be used to measure symptoms of depression. The PHQ-8 is comprised of 8 items rated 0 to 3 with 0 representing 'not at all' and 3 representing 'nearly every day'.
Time frame: Weeks 0,6 and 12
Symptoms of anxiety
The self-report Generalised Anxiety disorder-7 scale will be used to measure symptoms of anxiety. The GAD-7 is comprised of 7 questions rated 0 to 3 indicating not at all, to nearly every day respectively.
Time frame: Weeks 0,6 and 12
Psychological Distress
The Kessler Psychological Distress Scale (K10) will be used to measure symptoms of psychological distress. The K10 is comprised of 10 questions rated on a 5-point likert scale. Scores range from 10-50.
Time frame: Weeks 0,6 and 12
Faecal gut microbiota (composition, alpha- and beta-diversity)
Measured by 16S community profiling (Illumina Miseq) of bacterial genomic DNA isolated from stool samples.
Time frame: Week 0 and 12
Faecal short-chain fatty acids (SCFA)
Measured by gas liquid chromatography of stool samples
Time frame: Week 0 and 12
Faecal water
Determined from stool samples by oven-drying
Time frame: Week 0 and 12
Gut symptoms
Measured using the Gastrointestinal Symptom Rating Scale (GSRS) (7-day diary; questionnaire)
Time frame: Week 0 and 12
Stool frequency
Measured using self-reported number bowel movements daily recorded in a 7-day diary.
Time frame: Week 0 and 12
Stool consistency
Measured using the Bristol stool form scale (7-day dairy; questionnaire)
Time frame: Week 0 and 12
Serum Vitamin E levels
Measured in blood sample. Analysis of serum vitamin E levels by Liquid chromatography-mass spectrometry.
Time frame: Week 0 and 12
Dietary intake
Measured using a 7-day food and drink diary
Time frame: Week 0 and 12
Acceptability of snack products
Measured using an Acceptability of dietary intervention questionnaire developed by King's College London for use in dietary intervention studies. The questionnaire assesses acceptability using a number of domains including flavour, texture and portion size.
Time frame: Week 12
Snack compliance
Measured via the return of unused snacks at the final visit (consumption of \>75% of total snacks will be considered compliant).
Time frame: Week 12
Adverse events
Interview-administered questionnaire
Time frame: Week 0 to 12
Symptoms of depression and anxiety
Symptoms of depression and anxiety as measured by the Patient Health Questionnaire Anxiety and Depression Scale (PHQ-ADS). This is a 15-item self-report likert scale comprising the PHQ-8 and GAD-7. Scores can range from 0 to 48, cut points of 10,20 and 30 indicate mild, moderate and severe levels of depression/anxiety respectively.
Time frame: Week 0,6 and 12
Change in symptoms of depression and anxiety
Change symptoms of depression and anxiety as measured by the Patient Health Questionnaire Anxiety and Depression Scale (PHQ-ADS). This is a 15-item self-report likert scale comprising the PHQ-8 and GAD-7. Scores can range from 0 to 48, cut points of 10,20 and 30 indicate mild, moderate and severe levels of depression/anxiety respectively.
Time frame: Week 0, 6 and 12
Proportion of people with no, mild, moderate and severe symptoms of anxiety and depression
Measured by the Patient Health Questionnaire Anxiety and Depression Scale (PHQ-ADS). This is a 15-item self-report likert scale comprising the PHQ-8 and GAD-7. Scores can range from 0 to 48, cut points of 10,20 and 30 indicate mild, moderate and severe levels of depression and anxiety respectively.
Time frame: Week 0, 6 and 12
Proportion of people with no, mild, moderate and severe symptoms of depression
Measured by the PHQ-8 questionnaire. Scores can range from 0 to 24, cut points of 5, 10, 15 and 20 indicate mild, moderate, moderately severe and severe levels of depression, respectively.
Time frame: Week 0, 6 and 12
Proportion of people with no, mild, moderate and severe symptoms of anxiety
Measured by the GAD-7. The GAD-7 is comprised of 7 questions rated 0 to 3 indicating not at all, to nearly every day respectively and scores range from 0-21. Cut points are 5, 10 and 15 indicating mild, moderate and severe levels of anxiety, respectively.
Time frame: Week 0, 6 and 12