Sustained Meat and Alternative Intake (PRotEin DIet SatisfacTION Trial 4) (PREDITION)

Sustained Wellbeing Benefits of Red Meat Consumption in a Modern Flexitarian Diet: A Study Protocol for a 10 Week Randomised Clinical Trial

Introduction The trend of flexitarian eating patterns is on the rise, with young adults amongst the biggest adopters claiming health and environmental reasons to reduce red meat intake. Nutrient dense meat and animal products are often the lynchpin of these diets, even when consumed only occasionally and in moderate amounts. Red meat provides forms and concentrations of essential proteins, lipids, and micronutrients that are scarce in exclusively vegetarian regimens. The aim of this investigation is to consider the effects of moderate consumption of lean red meat as part of an otherwise vegetarian balanced diet and its impact on biomarkers of sustained health and wellbeing.

Methods and analyses A cohort of healthy, young (20-34 years) male and female participants will take part in two-arm parallel, randomised-controlled trial for a duration of 12 weeks, with a 3-month post follow-up. The trial will commence with a two-week assessment period followed by allocation to the intervention arms. The intervention will include the consumption of red meat or meat-alternatives three times per week for 10 weeks. Blood samples of the participants will be measured for changes in erythrocyte fatty acid distribution, circulating amino acids, neurotransmitters, markers of mineral status and inflammatory markers. Questionnaires to assess wellbeing and mental health will be undertaken every two weeks. Body composition, physical function test, blood measurements will be assessed at allocation (t0), week five into the intervention (t5) and post intervention (t10).

Discussion To our knowledge this is the first randomised controlled trial (RCT) investigating the overarching health consequences of consuming NZ pasture fed red meat or no meat, as part of a healthy diet.

Ethics and dissemination The trial was approved by the New Zealand Ministry of Health's Health and Disability Ethics Committees (20/STH/157).

Study Overview

• Status: Completed
• Conditions: Well-being
• Intervention / Treatment: Other: Non-red meat

Detailed Description

Study Design and Setting The study is a parallel RCT comprising a 2-week pre-intervention assessment, a 10-week intervention period and a 22-week post follow up. Participants will all eat a balanced plant-based basal diet and be randomised to also consume either red meat ('Flexitarian' arm) or a meat substitute ('Vegetarian' arm). The meat will be pasture-raised beef and lamb butchered and packaged to our specifications in New Zealand, while the meat substitute will be commercially available plant-based products.

Recognising that there are many interpretations of the terms vegetarian and flexitarian, in this study we define vegetarian as ovo-lacto vegetarian and flexitarian as 'a vegetarian diet with moderate amounts of red meat'. Both arms can consume eggs and dairy products, but no chicken, pork or fish, and no red meat other than that supplied by the researchers.

The study is designed around pairs of young adult consumers who share meals and are therefore likely to engage over the values and challenges of developing a healthy lifestyle. Each couple/household unit (see Recruitment) will receive a weekly delivery of a vegetarian meal kit containing complete ingredients for cooking 3-4 evening meals. Depending on their allocation, the couple will also receive an allotment of frozen red meat or meat-analogue to use for preparing 3 additional evening meals. To facilitate cooking and keep the behaviours of the arms aligned, we will provide recipe cards, shopping guidance and video instructions. All other meals during the week are self-catered and must adhere to study guidelines.

The quantity of meat will be sufficient to provide 350-500 g cooked weight per person per week. This conforms to the latest international recommendations for maximum intake 7 and the reported typical frequencies of red meat consumption. The meat alternative will be similar in quantity, form and function. It is vegetarian-friendly and serves to balance the total protein and fat intake of the arms.

Changes in objective and self-assessed subjective health variables over time and between arms will be investigated. These include physical function, body composition, metabolic health biomarkers and psychological wellbeing.

• Study Type: Interventional
• Enrollment (Actual): 80
• Phase: Not Applicable

Contacts and Locations

Study Locations

• New Zealand
  • [other]
    • Auckland, [other], New Zealand, 1142
      • The University of Auckland

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 20 years to 35 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion criteria:

• All participants are required to be omnivores who in the last 2 months consumed at least 2-3 meals per week containing meat of any description (red or white fleshed meat, including fish).
• All participants must be willing to consume both red meat and meat-analogues for the purposes of the trial.

Exclusion criteria:

• Obesity (BMI ≥ 30 kg/m2),
• Hyperlipidaemia
• Anosmia and ageusia (issues with smell and taste),
• Use of medications (except for occasional NSAIDs and antihistamines) or recreational drugs, or who smoke tobacco
• Disordered eating

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: red meat consumers; Consumes red meat 3 times a week	Other: Non-red meat; Red meat analogues and alternatives
Experimental: non-red meat consumers; Consumes a non-red meat comparison product 3 times a week	Other: Non-red meat; Red meat analogues and alternatives

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Polyunsaturated fatty acids	Concentrations of polyunsaturated fatty acids (18:2 n-6, 18:3 n-3, 20:4 n-6, 20:5 n-3, 22:5 n-3, 22:6 n-3) in erythrocyte membranes	Baseline to 10 week comparison

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Psychological and mental wellbeing	Multidimensional Fatigue Symptom Inventory Short Form (MSFI-SF). The Total MFSI-SF score ranges from -24 to 96, with higher values indicating greater fatigue. The five subscales of the MFSI each ranges from 0 to 24: General subscale = ranges from 0 to 24, with higher values indicating greater fatigue (worse outcomes); Physical subscale = ranges from 0 to 24, with higher values indicating greater fatigue (worse outcomes); Emotional subscale = ranges from 0 to 24, with higher values indicating greater fatigue (worse outcomes); Mental subscale = ranges from 0 to 24, with higher values indicating greater fatigue (worse outcomes); Vigor subscale = ranges from 0 to 24, with higher values indicating greater vigor (better outcomes) Total MFSI-SF score = (General + Physical + Emotional + Mental) - Vigor = Total Score ranges from -24 to 96 with higher values indicating greater fatigue (worse outcomes).	Change from baseline to 10 week comparison
Psychological and mental wellbeing	Depression Anxiety Stress Scales-Short form (DASS-21) Depression score ranges from 0 to 42 (raw scores 0 to 21, which are then multiplied by 2 to be equivalent to the DASS-42), with higher numbers indicating greater depression (worse outcome). Anxiety score ranges from 0 to 42 (raw scores 0 to 21, which are then multiplied by 2 to be equivalent to the DASS-42), with higher numbers indicating greater anxiety (worse outcome). Stress score ranges from 0 to 42 (raw scores 0 to 21, which are then multiplied by 2 to be equivalent to the DASS-42), with higher numbers indicating greater stress (worse outcome).	Change from baseline to 10 week comparison
Psychological and mental wellbeing	WHO-Five Well-Being Index (WHO 5). The raw score ranges from 0 to 25, with 0 representing the worst and 100 representing the best possible quality of life The percentage score ranges from 0 to 100, with 0 representing the worst and 100 representing the best possible quality of life	Change from baseline to 10 week comparison
Psychological and mental wellbeing	Positive Eating Scale (PES) Total Positive Eating score (PES-Tot) = ranges from 1 to 4, with higher values indicating better experiences with eating Satisfaction with Eating subscale (PES-Sat) = ranges from 1 to 4, with higher values indicating more satisfaction with eating Pleasure when Eating subscale (PES-Pl) = ranges from 1 to 4, with higher values indicating more pleasure when eating	Change from baseline to 10 week comparison

Collaborators and Investigators

• Sponsor: University of Auckland, New Zealand
• Collaborators: University of Otago; AgResearch

Publications and helpful links

General Publications

• Braakhuis A, Gillies N, Worthington A, Knowles S, Conner T, Roy R, Pham T, Bermingham E, Cameron-Smith D. A Modern Flexitarian Dietary Intervention Incorporating Web-Based Nutrition Education in Healthy Young Adults: Protocol for a Randomized Controlled Trial. JMIR Res Protoc. 2021 Dec 21;10(12):e30909. doi: 10.2196/30909.

Study record dates

Study Major Dates

• Study Start (Actual): May 17, 2021
• Primary Completion (Actual): December 22, 2021
• Study Completion (Actual): September 30, 2022

Study Registration Dates

• First Submitted: April 18, 2021
• First Submitted That Met QC Criteria: April 28, 2021
• First Posted (Actual): May 3, 2021

Study Record Updates

• Last Update Posted (Actual): November 28, 2023
• Last Update Submitted That Met QC Criteria: November 27, 2023
• Last Verified: November 1, 2023

More Information

Terms related to this study

• Keywords: nutrition; mental health; meat
• Other Study ID Numbers: 5000927-4

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Access to data will be granted to appropriate members of the research team and to authorised representatives from the host institution to monitor or audit the study and ensure compliance with regulations. Data will be made available to external academics on reasonable request.
• IPD Sharing Time Frame: Data will be made available when he study is complete (July 2022)
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; ICF; CSR

Drug and device information, study documents

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