Dietary Intervention Study on Food Based Dietary Guidelines for Sustainable and Healthy Lifestyles

Study Overview
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Brief Summary
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The aim of the study is to provide proof of the effectiveness, acceptability, healthfulness and nutritional adequacy of dietary guidelines to reduce greenhouse gas emissions. The study will compare the effect of dietary advice based on 1) healthy climate-friendly dietary guidelines (intervention group) or 2) standard healthy dietary guidelines (control) on greenhouse gas emissions associated with dietary intake over 12 weeks.

Detailed Description
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A randomised, parallel controlled trial will recruit n=360 healthy adults (age 18-64) across three research centres. After successful screening and receiving informed consent, participants will be randomised into the intervention or the control group for the duration of the 12-week trial described in detail in the text and figure below. The intervention group will receive dietary advice based on climate friendly eating recommendations. The control group will receive dietary recommendations based on Healthy Ireland's Healthy Eating Guidelines and Food Pyramid (FSAI, 2019). Prior to their first onsite visit, participants will be asked to complete a Health and Lifestyle questionnaire and dietary assessment. The dietary assessment will include 3 online 24-hour recalls (2 non-consecutive weekdays and 1 weekend day) (via web-based dietary recall tool, Foodbook24) a food frequency questionnaire (Foodbook24) Baseline, Visit 1 (Week 0): We will collect blood and urine samples from participants and record anthropometric measurements. Participants will be asked to complete a Stage of Change questionnaire to assess their openness to a diet change. All participants will complete a Food Waste Questionnaire at baseline for later comparison at endpoint. At the end of Visit 1 participants will receive a personalised feedback report and advice from nutritionists based on their habitual diet. Week 6: Participants will be asked to complete a second dietary assessment during week 6. 3 24-hour recalls and a food frequency questionnaire will be hosted on Foodbook24, a web-based dietary recall tool. Week 11: Before attending endpoint onsite visit, participants will complete a final dietary assessment. The same assessment as Pre-baseline and Week 6 will be used. Endpoint, Visit 2 (Week 12): At the end of 12 weeks, participants will be invited back for a follow-up assessment. Blood and urine samples and anthropometrics will be collected/recorded. Participants will complete the Stage of Change questionnaire and Food Waste questionnaire. A Tolerance questionnaire will be administered to see how willing participants would be to continue with their prescribed diet.

Official Title
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Dietary Intervention Study on Food Based Dietary Guidelines for Sustainable and Healthy Lifestyles

Conditions
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Dietary Habits, Healthy Diet, Healthy Nutrition, Personalized Nutrition

Intervention / Treatment
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* Behavioral: Healthy climate-friendly dietary guidelines
* Behavioral: Healthy dietary guidelines


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Provide written informed consent Be a healthy adult between the ages of 18-64 years old Consume a diet associated with moderate-high greenhouse gas emissions Be in good general health Exclusion Criteria: Are pregnant, lactating or planning to become pregnant Are following a medically prescribed diet Have a diagnosis of an acute or chronic medical condition that could interfere with the outcomes of the study. Such diagnoses include (but are not limited to) cardiovascular disease, diabetes mellitus, inflammatory bowel disease, cancers (within the last 5 years), etc. Are immunocompromised or have a suspected immunodeficiency Have excessive alcohol intake (>28 units per week) Have a known food allergy Regularly consume a single high-dose vitamin or mineral supplement Are participating in another research study Are unable to read, write or understand English.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 64 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Parallel randomized control trial
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Healthy climate-friendly dietary guidelines<br>Personalised healthy dietary recommendations aimed at reducing diet-related greenhouse gas emissions | Behavioral: Healthy climate-friendly dietary guidelines<br>* Personalised climate-friendly healthy dietary recommendations<br>|
| Active Comparator: Healthy eating guidelines<br>Personalised healthy dietary recommendations based on Ireland's Healthy Eating Guidelines | Behavioral: Healthy dietary guidelines<br>* Personalised healthy dietary recommendations<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Diet-related greenhouse gas emissions reported as kilograms of carbon dioxide equivalents per day | Participants will record their diet at baseline (habitual diet) and endpoint (intervention diet) using an online 24-hour recall method. Diet-related greenhouse gas emissions will be estimated using food, nutrient and food-related greenhouse gas emissions databases (measured as kilograms of carbon dioxide equivalents). The primary outcome measure is the change in diet-related greenhouse gas emissions (kgCO2-eq/day) as a result of the intervention diet. | 12 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Calcium intake (milligrams per day) | Calcium intake will be calculated using dietary intake records (3x 24-hour recalls) at baseline and endpoint (intervention diet). The secondary outcome measure is the change in calcium intake (mg/day) as a result of the intervention diet. | 12 weeks | 
| Iron intake (milligrams per day) | Iron intake will be calculated from dietary intake records (3x 24-hour recalls) at baseline and endpoint (intervention diet). The secondary outcome measure is the change in iron intake (mg/day) as a result of the intervention diet. | 12 weeks | 
| Urinary iodine (micrograms per liter) | Participants will provide urine samples at baseline (Week 0) and endpoint (Week 12). Urinary iodine concentrations (ug/L) will be measured. The secondary outcome measure is the change in urinary iodine as a result of the intervention diet. | 12 weeks | 
| Serum vitamin D status (25(OH)D nanomole per liter) | Participants will provide blood samples at baseline (Week 0) and endpoint (Week 12). 25(OH)D will be measured (nmol/L) as a marker of vitamin D status. The secondary outcome measure is the change in vitamin D as a result of the intervention diet. | 12 weeks | 
| Serum lipids (milimoles per liter) | Participants will provide blood samples at baseline (Week 0) and endpoint (Week 12). Serum lipids, including total cholesterol, HDL cholesterol and triglycerides (mmol/L) will be measured. The secondary outcome measure is the change in lipid profile as a result of the intervention diet. | 12 weeks | 
| Fasting glucose (milimoles per liter) | Participants will provide blood samples at baseline (Week 0) and endpoint (Week 12). Fasting blood glucose will be measured (mmol/L). The secondary outcome measure is the change in fasting glucose as a result of the intervention diet. | 12 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Sustainable diets, Greenhouse gas emissions, Climate-friendly, Personalized nutrition