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Trial registered on ANZCTR


Registration number
ACTRN12616001606471
Ethics application status
Approved
Date submitted
17/11/2016
Date registered
21/11/2016
Date last updated
12/12/2018
Type of registration
Prospectively registered

Titles & IDs
Public title
Do moderate protein, high carbohydrate predominantly plant-based diets assist in appetite control and improve short-term health outcomes in individuals aged 65-75 years?
Scientific title
Do moderate protein, high carbohydrate predominantly plant-based diets assist in appetite control and improve short-term health outcomes in individuals aged 65-75 years?
Secondary ID [1] 290491 0
Nil known
Universal Trial Number (UTN)
U1111-1189-6455
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
obesity 300877 0
metabolic syndrome 300881 0
Condition category
Condition code
Diet and Nutrition 300697 300697 0 0
Obesity
Metabolic and Endocrine 300820 300820 0 0
Metabolic disorders

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Eligible participants will be invited to attend a baseline testing morning at the RPA-CPC Clinic. Male and female subjects aged 65-75 years will be randomly assigned to one of four diets for 4wks. Each of the dietary interventions will be manipulated to provide 15% of energy as protein but will differ in the ratio of plant to animal proteins and the proportion of carbohydrate and fat.

The 4 dietary arms are as follows:
Arm 1: high plant to animal ratio (15% protein (38% plant, 62% animal), 61% carbohydrate, 24% fat)
Arm 2: high plant to animal ratio (15% protein (18% plant, 82% animal), 48% carbohydrate, 37% fat)
Arm 3: low plant to animal ratio (15% protein (18% plant, 82% animal), 61% carbohydrate, 24% fat)
Arm 4: low plant to animal ratio (15% protein (38% plant, 62% animal), 48% carbohydrate, 37% fat)

Prepared meals, snacks and fruit will be delivered once per week for 4 weeks to participants homes. Participants will be asked to eat ad libitum, to only consume study foods delivered to them and to keep a weighed food diary. Participants will be provided with scales and a food diary and will be asked to keep a weighed record of their intake. Participants will be asked to provide their own drinks and to avoid soft drinks and alcoholic beverages during the study. Each participant will be contacted by phone to ensure the first food delivery has been received and for 4 x 48hr food recalls during the intervention.
Intervention code [1] 296348 0
Treatment: Other
Comparator / control treatment
Comparisons will be as follows:
Arm 1 versus Arm 2
Arm 3 versus Arm 4
Arm 1 versus Arm 3
Arm 2 versus Arm 4
Control group
Active

Outcomes
Primary outcome [1] 300127 0
Study energy and macronutrient intake (MJ): Participants will be given ad libitum access to study food and will be asked to consume no other foods during the 4-wk intervention. This will allow participants to eat ad libitum from a diet of fixed macronutrient composition. Each participant will be supplied with kitchen scales and asked to keep a weighed food record throughout the study. Participants will record intake following each meal in the study food diary provided.
Timepoint [1] 300127 0
Participants will record the weight of food consumed throughout the 4 week dietary intervention.
Primary outcome [2] 300128 0
Fasting plasma levels of fibroblast growth factor-21.
Timepoint [2] 300128 0
Fasted plasma samples will be collected prior to the start of the 4wk dietary intervention and on completion of the 4wk dietary intervention.
Secondary outcome [1] 329120 0
Fasting serum levels of glucose.
Timepoint [1] 329120 0
Fasted serum samples will be collected prior to the start of the 4wk dietary intervention and on completion of the 4wk dietary intervention.
Secondary outcome [2] 329123 0
Fasting serum levels of cholesterol.
Timepoint [2] 329123 0
Fasted serum samples will be collected prior to the start of the 4wk dietary intervention and on completion of the 4wk dietary intervention.
Secondary outcome [3] 329124 0
Fasting serum levels of HDL cholesterol.
Timepoint [3] 329124 0
Fasted serum samples will be collected prior to the start of the 4wk dietary intervention and on completion of the 4wk dietary intervention.
Secondary outcome [4] 329125 0
Fasting plasma levels of high sensitivity C-reactive protein.
Timepoint [4] 329125 0
Fasted serum samples will be collected prior to the start of the 4wk dietary intervention and on completion of the 4wk dietary intervention.
Secondary outcome [5] 329127 0
Fasting serum levels of branched chain amino acids.
Timepoint [5] 329127 0
Fasted serum samples will be collected prior to the start of the 4wk dietary intervention and on completion of the 4wk dietary intervention.
Secondary outcome [6] 329128 0
Fasting serum levels of liver function enzymes.
Timepoint [6] 329128 0
Fasted serum samples will be collected prior to the start of the 4wk dietary intervention and on completion of the 4wk dietary intervention.
Secondary outcome [7] 329129 0
Fasting levels of cytokines will be measured in peripheral blood mononuclear (PBMC) cells by flow cytometry. PBMCs will be extracted from fasting plasma samples.
Timepoint [7] 329129 0
Fasted serum samples will be collected prior to the start of the 4wk dietary intervention and on completion of the 4wk dietary intervention.
Secondary outcome [8] 329130 0
Levels of short chain fatty acids (SCFA) in stool samples will be measured by NMR.
Timepoint [8] 329130 0
Participants will be asked to collect one stool sample prior to the start and end of the 4wk dietary intervention.
Secondary outcome [9] 329131 0
Gut microbiome will be measured from bacterial DNA extracted from the stool sample.
Timepoint [9] 329131 0
Participants will be asked to collect one stool sample prior to the start and end of the 4wk dietary intervention.
Secondary outcome [10] 329132 0
A timed chair stand test will be measured as an indicator of physical performance. Participants will be required to rise five times as fast as possible with their arms folded from a standard height (43cm) chair. Performance will be measured as time (seconds) from the initial seated position to the final seated position after completing five stands.
Timepoint [10] 329132 0
Physical performance will be measured prior to the start of the intervention and on completion of the 4wk dietary intervention.
Secondary outcome [11] 329133 0
Gait/walk speed will be measured as an indicator of physical performance. Starting from a standing position, participants will be required to walk in their usual pace between two lines marked six metres (6-m) apart on the floor in the testing room; the time taken to walk the 6m will be timed with a stopwatch. Gait/walk speed (6m) is calculated as the average of two trial (metre/second).
Timepoint [11] 329133 0
Physical performance will be measured prior to the start of the intervention and on completion of the 4wk dietary intervention.
Secondary outcome [12] 329134 0
Grip strength will be measured as an indicator of physical performance. Grip strength (kg) of both hands will be determined using a Jamar dynamometer (Jamar, Bolingbrook, IL) and average of best result will be used.
Timepoint [12] 329134 0
Physical performance will be measured prior to the start of the intervention and on completion of the 4wk dietary intervention.
Secondary outcome [13] 329135 0
24 hour levels of urinary urea.
Timepoint [13] 329135 0
Participants will be asked to collect 24hr urine sample prior to the start and end of the 4wk dietary intervention.
Secondary outcome [14] 329136 0
Blood pressure will be measured by Omron Standard Blood Pressure Monitor.
Timepoint [14] 329136 0
Measurements will be made prior to and on completion of the 4wk dietary intervention.
Secondary outcome [15] 329138 0
Waist circumference using a tape measure
Timepoint [15] 329138 0
Measurements will be made prior to and on completion of the 4wk dietary intervention.
Secondary outcome [16] 329139 0
Body weight using a digital scale
Timepoint [16] 329139 0
Measurements will be made prior to and on completion of the 4wk dietary intervention.
Secondary outcome [17] 329140 0
Body height using a fixed stadiometer.
Timepoint [17] 329140 0
Measurements will be made prior to the 4wk dietary intervention.
Secondary outcome [18] 329142 0
Body composition will be measured using BodPod.
Timepoint [18] 329142 0
Measurements will be made prior to and on completion of the 4wk dietary intervention.
Secondary outcome [19] 329143 0
Appetite rating using visual analogue scales.
Timepoint [19] 329143 0
Appetite questionnaires will be completed on one day during each week of the 4wk dietary intervention. Questionnaires will be completed hourly from before breakfast until 10pm.
Secondary outcome [20] 329147 0
Food palatability ratings using visual analogue scales.
Timepoint [20] 329147 0
Palatability questionnaires will be completed on one day of each week during the 4wk dietary intervention. Questionnaires will be completed for each food the participant consumes.
Secondary outcome [21] 329148 0
Lifestyle and general health will be assessed by questionnaire. This will include a collection of validated questionnaires including the CAGE questionnaire, physical activity scale for the elderly (PASE), geriatric depression scale (GDS), the 12-item short form health survey and Activities of Daily Living (ADL).
Timepoint [21] 329148 0
Lifestyle and general health will be assessed prior to commencement of the 4wk dietary intervention.
Secondary outcome [22] 329355 0
Assess tooth plaque using a Sillness and Loe Plaque Index.
Timepoint [22] 329355 0
Measurements will be made prior to and on completion of the 4wk dietary intervention.
Secondary outcome [23] 329358 0
Assess periodontal status and dentition using a Florida Probe to chart periodontal pocket depths, recession, bleeding, suppuration, teeth present/missing, restorations and prosthodontics.
Timepoint [23] 329358 0
Measurements will be made prior to and on completion of the 4wk dietary intervention.
Secondary outcome [24] 329360 0
Measure gingival crevicular fluid volume using a Periotron 8010 to collect GCF fluid at 2 separate gingival crevice sites
Timepoint [24] 329360 0
Measurements will be made prior to and on completion of the 4wk dietary intervention.
Secondary outcome [25] 329361 0
Measure salivary amylase 1 concentration in unstimulated saliva flow
Timepoint [25] 329361 0
Measurements will be made prior to and on completion of the 4wk dietary intervention.
Secondary outcome [26] 329362 0
Collect stimulated saliva flow for analysis of protective potential.
Timepoint [26] 329362 0
Measurements will be made prior to and on completion of the 4wk dietary intervention.
Secondary outcome [27] 329400 0
Collect tooth plaque for measurement of bacterial composition.
Timepoint [27] 329400 0
Measurements will be made prior to and on completion of the 4wk dietary intervention.

Eligibility
Key inclusion criteria
Females (post-menopausal) or males, 65-75 years, BMI 20-35kg/m2 will be recruited.
Minimum age
65 Years
Maximum age
75 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Exclusion criteria will include diabetes mellitus (insulin dependent, Type 1 or 2), renal or liver disease, cancer or active neoplasms, hyperthyroidism (unless treated or under control), taking medications known to affect weight or energy expenditure, unintentional weight loss (>10% body weight) over the past 5 years, smoking, alcohol intake > 3 drinks/day, vegan and vegetarians, food allergies and/or intolerances, and when changes in diet are contraindicated by treating doctor.

Study design
Purpose of the study
Prevention
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation was concealed using central randomisation (computer) and was performed following identification of eligible participants.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Male and female groups will be randomized to each intervention using permuted block randomisation. The will be done using the R package “blockrand” for males and females separately..
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s


Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
Linear mixed model regression with and without covariates to test for differences between the 4 dietary interventions. Linear regression and/or general additive models in R will be used to test the relationship between habitual dietary intakes and baseline measures.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
28/11/2016
Actual
3/04/2017
Date of last participant enrolment
Anticipated
30/09/2017
Actual
7/05/2018
Date of last data collection
Anticipated
30/11/2017
Actual
4/06/2018
Sample size
Target
200
Accrual to date
Final
129
Recruitment in Australia
Recruitment state(s)
NSW
Recruitment hospital [1] 6910 0
Royal Prince Alfred Hospital - Camperdown
Recruitment postcode(s) [1] 14579 0
2050 - Camperdown

Funding & Sponsors
Funding source category [1] 294918 0
Other
Name [1] 294918 0
an individual, philanthropic donation to the University
Country [1] 294918 0
Australia
Primary sponsor type
University
Name
The University of Sydney
Address
The University of Sydney
NSW, 2006
Australia
Country
Australia
Secondary sponsor category [1] 293753 0
None
Name [1] 293753 0
Not applicable
Address [1] 293753 0
Not applicable
Country [1] 293753 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 296295 0
Sydney Local Health District - RPAH
Ethics committee address [1] 296295 0
Research and Ethics Governance Office
RPAH Medical Centre
Suite 210A, 100 Carillion Avenue
NEWTOWN, NSW 2042
Ethics committee country [1] 296295 0
Australia
Date submitted for ethics approval [1] 296295 0
28/06/2016
Approval date [1] 296295 0
07/11/2016
Ethics approval number [1] 296295 0
X16-0285 & HREC/16/RPAH/364

Summary
Brief summary
The primary aim of the current study is to determine the effect of a moderate protein, high carbohydrate predominantly plant-based diet on appetite control and short-term health outcomes in individuals 65-75 years of age using a meal delivery based dietary intervention. 220 subjects, comprising equal numbers of men and women will be recruited. Participants will attend the RPA-CPC Clinic on 3 occasions. The first will be to attend a screening interview where they will be asked to complete questionnaires on their medical history, medications, cognitive health and eating behaviour. Eligible participants will then be invited to attend a baseline testing morning at the RPA-CPC Clinic. At the baseline testing, participants will arrive after an overnight fast with un-brushed teeth, bringing with them a 7d food diary, completed questionnaires about their lifestyle and general health, a stool sample and a 24hr urine collection. A blood sample will be collected and then an oral health examination will be performed and saliva and bacterial samples from tooth-surfaces will be collected. Body weight, waist and hip circumference, blood pressure, body composition and physical performance will also be measured. Participants will be randomly assigned to one of four dietary interventions. On the week after baseline testing study diets will be provided via a meal delivery company. Participants will be asked to consume the foods ad libitum. Participants will be requested to consume only from study foods and to keep a weighed food diary. During the 4 wk intervention, a study co-ordinator will contact each participant by phone on 5 different occasions. The first will be to ensure food has been delivered on the day before the study is to start, and the remaining 4 calls will be for a 48hr food recall. At the end of the final week of the dietary intervention participants will attend the RPA-CPC Clinic for final testing. At final testing, participants will arrive after an overnight fast with un-brushed teeth and will bring with them their study diary and a 24hr urine collection. A blood sample will be collected and an oral health examination will be performed and saliva and bacterial samples from tooth-surfaces will be collected. Measurements of body weight, waist and hip circumference, blood pressure, body composition and physical performance will be repeated.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 63278 0
Dr Alison Gosby
Address 63278 0
Level 4
Charles Perkins Centre, Bldg D17
The University of Sydney
NSW, 2006
Country 63278 0
Australia
Phone 63278 0
+61 2 8627 1689
Fax 63278 0
Email 63278 0
[email protected]
Contact person for public queries
Name 63279 0
Dr Alison Gosby
Address 63279 0
Level 4
Charles Perkins Centre, Bldg D17
The University of Sydney
NSW, 2006
Country 63279 0
Australia
Phone 63279 0
+61 2 8627 1689
Fax 63279 0
Email 63279 0
[email protected]
Contact person for scientific queries
Name 63280 0
Dr Alison Gosby
Address 63280 0
Level 4
Charles Perkins Centre
The University of Sydney
NSW, 2006
Country 63280 0
Australia
Phone 63280 0
+61 2 8627 1689
Fax 63280 0
Email 63280 0
[email protected]

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