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Trial registered on ANZCTR


Registration number
ACTRN12624001102561
Ethics application status
Approved
Date submitted
29/08/2024
Date registered
12/09/2024
Date last updated
12/09/2024
Date data sharing statement initially provided
12/09/2024
Type of registration
Prospectively registered

Titles & IDs
Public title
Impact of increased dietary fibre intake through dietetic counselling on endothelial function
Scientific title
Impact of increased dietary fibre intake through dietetic counselling on endothelial function in males aged 45 years and above and post-menopausal females
Secondary ID [1] 312773 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Unhealthy diet 334824 0
Condition category
Condition code
Diet and Nutrition 331378 331378 0 0
Other diet and nutrition disorders
Cardiovascular 331569 331569 0 0
Normal development and function of the cardiovascular system

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Dietary advice to increase dietary fibre intake to 40 g per day using a whole of diet approach for 3 months, with a follow up at 6 months from commencement. This group will focus on consuming fibre from a variety of fibre rich foods (whole grains, legumes, vegetables, fruit, nuts and seeds), by slowly increasing fibre intake over the first 4 weeks to increase to 40 g fibre per day. Participants will see the study dietitian in person at baseline (~1 hour), and via telephone or Zoom at weeks 2, 4, and 8 (~30 minutes each). To monitor dietary adherence, participants will provide a food diary prior to each study day visit (baseline, 3 months and 6 months), prior to dietitian appointments (weeks 2, 4, and 8), and at 4 months and 5 months after commencement.

At study visits (baseline and 3 months only), participants can self nominate to opt in to a postprandial meal challenge (rather than fasting only). After fasting measures have been taken, participants will be provided with a high fat, high refined sugar meal to consume within 15 minutes, and flow mediated dilation will be tested at 2 hours, 4 hours and 6 hours post meal consumption. The first 10 participants in each group to opt in will be chosen for the postprandial meal challenge.
Intervention code [1] 329302 0
Lifestyle
Comparator / control treatment
Dietary advice lower carbohydrate diet, rich in healthy unsaturated fats using a whole of diet approach for 3 months, with a follow up at 6 months from commencement. This group will focus on consuming foods lower in saturated fat and higher in mono- and polyunsaturated fat, aiming for a total fat intake of ~40% total energy. Participants will see the study dietitian in person at baseline (~1 hour), via telephone or Zoom at weeks 2, 4, and 8 (~30 minutes each). To monitor dietary adherence, participants will provide a food diary prior to each study day visit (baseline, 3 months and 6 months), prior to dietitian appointments (weeks 2, 4, and 8), and at 4 months and 5 months after commencement.

At study visits (baseline and 3 months only), participants can self nominate to opt in to a postprandial meal challenge (rather than fasting only). After fasting measures have been taken, participants will be provided with a high fat, high refined sugar meal to consume within 15 minutes, and flow mediated dilation will be tested at 2 hours, 4 hours and 6 hours post meal consumption. The first 10 participants in each group to opt in will be chosen for the postprandial meal challenge.
Control group
Active

Outcomes
Primary outcome [1] 339134 0
Endothelial function
Timepoint [1] 339134 0
Baseline and 3 months after commencement (primary endpoint)
Follow up at 6 months after commencement
Secondary outcome [1] 438883 0
Cholesterol
Timepoint [1] 438883 0
Baseline and 3 months after commencement
Follow up at 6 months after commencement
Secondary outcome [2] 438884 0
Fasting triglycerides
Timepoint [2] 438884 0
Baseline and 3 months after commencement
Follow up at 6 months after commencement
Secondary outcome [3] 438885 0
Fasting glucose
Timepoint [3] 438885 0
Baseline and 3 months after commencement
Follow up at 6 months after commencement
Secondary outcome [4] 438886 0
Fasting insulin
Timepoint [4] 438886 0
Baseline and 3 months after commencement
Follow up at 6 months after commencement
Secondary outcome [5] 438887 0
Anthropometry
Timepoint [5] 438887 0
Baseline and 3 months after commencement
Follow up at 6 months after commencement
Secondary outcome [6] 438888 0
Blood pressure
Timepoint [6] 438888 0
Baseline and 3 months after commencement
Follow up at 6 months after commencement
Secondary outcome [7] 438889 0
Appetite
Timepoint [7] 438889 0
Baseline and 3 months after commencement
Follow up at 6 months after commencement
Secondary outcome [8] 438890 0
Gastrointestinal symptoms (stool consistency and bloating). This will be assessed as a composite outcome.
Timepoint [8] 438890 0
Baseline and 3 months after commencement
Follow up at 6 months after commencement
Secondary outcome [9] 438895 0
Postprandial flow mediated dilation (in a subset of participants who choose to opt in)
Timepoint [9] 438895 0
0 hours, 2 hours, 4 hours, and 6 hours post meal consumption during the study visits at baseline and 3 months after commencement

Eligibility
Key inclusion criteria
Male aged 45 years and above, or female post menopause
Fibre intake less than 15 g/day
Minimum age
45 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Currently smoking or vaping
History of irritable bowel syndrome (IBS) (moderate to severe) or inflammatory bowel disease (IBD)
Gastrointestinal surgery the past 12 months
Major cardiovascular surgery (i.e., surgery that involves the heart or blood vessels)
Cardiovascular events the past 12 months (e.g., heart attack, stroke)
Implanted cardiac pace maker
Planning to start a new exercise program during the study
Using fibre or omega-3 supplements the past 1 month
Changes to medication use the past 6 weeks (e.g., if you have been on the same statin dose the past 6 weeks or long, you are eligible)

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)
Sealed opaque envelopes
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table created by computer software (i.e. computerised sequence generation)
Masking / blinding
Who is / are masked / blinded?



Intervention assignment
Other design features
Phase
Not Applicable
Type of endpoint/s
Statistical methods / analysis

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
27/01/2025
Actual
Date of last participant enrolment
Anticipated
2/06/2025
Actual
Date of last data collection
Anticipated
19/12/2025
Actual
Sample size
Target
42
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
VIC

Funding & Sponsors
Funding source category [1] 317206 0
University
Name [1] 317206 0
Monash University
Country [1] 317206 0
Australia
Primary sponsor type
University
Name
Monash University
Address
Country
Australia
Secondary sponsor category [1] 319625 0
None
Name [1] 319625 0
Address [1] 319625 0
Country [1] 319625 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 315943 0
Monash University Human Research Ethics Committee
Ethics committee address [1] 315943 0
https://www.monash.edu/researchoffice/ethics
Ethics committee country [1] 315943 0
Australia
Date submitted for ethics approval [1] 315943 0
07/07/2024
Approval date [1] 315943 0
09/08/2024
Ethics approval number [1] 315943 0
42726

Summary
Brief summary
Both dietary fibre and unsaturated fats are known for their health benefits on cardiovascular health, however, there are a lack of studies evaluating the effects of dietary fibre from whole foods on endothelial function. The purpose of the study is to assess the impact of a high fibre diet compared to a lower carbohydrate, high unsaturated fat diet on endothelial function, as an early indicator of cardiovascular disease risk. Males over 45 years old and females post menopause with a low dietary fibre intake of less than 15 g/day will be randomised to one of two groups: high fibre diet (40 g/day from whole foods - wholegrains, legumes, fruits, vegetables, nuts and seeds), or high unsaturated fat diet (approx. 40% energy intake from fat from whole foods). Participants will be provided with dietetic counselling to adhere to their allocated diet during the first 3 months of the study, with a follow up at 6 months from commencement. A subset of participants will be assessed in the postprandial phase (as a more sensitive marker or metabolic health), where they will be provided with a high fat, high sugar meal and have their endothelial function tested every 2 hours for up to 6 hours at baseline and 3 months. This study may help with the development of clinical practice guidelines for dietitians to provide dietary advice to patients for vascular health. We hypothesise that both diets will improve endothelial function.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 136298 0
Dr Aimee Dordevic
Address 136298 0
Monash University, 264 Ferntree Gully Rd, Notting Hill VIC 3168
Country 136298 0
Australia
Phone 136298 0
+61 3 9902 4270
Fax 136298 0
Email 136298 0
[email protected]
Contact person for public queries
Name 136299 0
Nina Trinquet
Address 136299 0
Monash University, 264 Ferntree Gully Rd, Notting Hill VIC 3168
Country 136299 0
Australia
Phone 136299 0
+61 3 9905 9762
Fax 136299 0
Email 136299 0
[email protected]
Contact person for scientific queries
Name 136300 0
Nina Trinquet
Address 136300 0
Monash University, 264 Ferntree Gully Rd, Notting Hill VIC 3168
Country 136300 0
Australia
Phone 136300 0
+61 3 9905 9762
Fax 136300 0
Email 136300 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
Yes
What data in particular will be shared?
All of the individual participant data collected during the trial, after de-identification.
When will data be available (start and end dates)?
Immediately following publication, with no end date determined.
Available to whom?
Only researchers who provide a methodologically sound proposal.
Available for what types of analyses?
Any purpose.
How or where can data be obtained?
Access subject to approval by Principal Investigator, Dr Aimee Dordevic ([email protected]).


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.