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

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.

Study Overview

• Status: Completed
• Conditions: Dietary Habits; Healthy Diet; Healthy Nutrition; Personalized Nutrition
• Intervention / Treatment: Behavioral: Healthy climate-friendly dietary guidelines; Behavioral: Healthy dietary guidelines

Detailed Description

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

1. 3 online 24-hour recalls (2 non-consecutive weekdays and 1 weekend day) (via web-based dietary recall tool, Foodbook24)
2. 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.

• Study Type: Interventional
• Enrollment (Actual): 355
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Ireland
  • Cork, Ireland
    • University College Cork
  • Dublin, Ireland, Dublin 4
    • University College Dublin
• United Kingdom
  • Belfast, United Kingdom
    • Queen's University Belfast

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 64 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

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

What is the study measuring?

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

Collaborators and Investigators

• Sponsor: University College Dublin
• Collaborators: Queen's University, Belfast; University College Cork; Teagasc
• Investigators: Principal Investigator: Aifric O'Sullivan, PhD, University College Dublin

Study record dates

Study Major Dates

• Study Start (Actual): March 21, 2022
• Primary Completion (Actual): June 1, 2023
• Study Completion (Actual): June 1, 2023

Study Registration Dates

• First Submitted: February 8, 2022
• First Submitted That Met QC Criteria: February 21, 2022
• First Posted (Actual): February 23, 2022

Study Record Updates

• Last Update Posted (Actual): October 4, 2023
• Last Update Submitted That Met QC Criteria: October 3, 2023
• Last Verified: October 1, 2023

More Information

Terms related to this study

• Keywords: Personalized nutrition; Sustainable diets; Greenhouse gas emissions; Climate-friendly
• Other Study ID Numbers: LS-21-51-Davies-OSullivan

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: At the start of the study each participant will have a study code assigned to them. All of the data from the trials will be stored using these unique study codes. A file will be set up which will be stored in a location separate to the study data. This file will contain a list which will link each participants contact details to the corresponding ID code. All stored information will be encrypted and protected by a password that only the researcher and PI will know.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No