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Trial registered on ANZCTR

Registration number

ACTRN12620000967987p

Ethics application status

Submitted, not yet approved

Date submitted

13/07/2020

Date registered

28/09/2020

Date last updated

28/09/2020

Date data sharing statement initially provided

28/09/2020

Type of registration

Prospectively registered

Titles & IDs

Public title

Assessing metabolic response curves during mixed meal tolerance testing in healthy European males

Scientific title

Assessing metabolic response curves during mixed meal tolerance testing in healthy European males

Secondary ID [1]

Nil Known

Universal Trial Number (UTN)

U1111-1249-5558

Trial acronym

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Type 2 diabetes

Insulin resistance / hyperinsulinaemia

Condition category

Condition code

Metabolic and Endocrine

Metabolic disorders

Diet and Nutrition

Obesity

Metabolic and Endocrine

Diabetes

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

Observing the metabolic responses following each of three different meals: 75g glucose in 300mL water (using the commercial standard 'Carbotest' drink); mixed meal smoothie (SMMT) (e.g. milk, blueberries, banana, protein powder), and whole food mixed meal (WMMT) (e.g. muesli, milk and fruit with eggs on Vogel's toast). The latter two will be prepared for participants based on the information provided from a three-day food diary and will provide approximately one-third of their personalised daily caloric requirement. The carbohydrate, protein and total fat content of the smoothies and the mixed meals will comprise 55%, 20%, and 25%, respectively, of this energy intake. Foods used may vary slightly depending on caloric requirements.

It is typical, and will be encouraged, for the glucose drink to be consumed within about 5 minutes. Participants will be timed eating the SMMT and WMMT. Ideally these meals will be consumed within 15 minutes.

It is anticipated that each test will take 3-3.5 hours to complete. (e.g. three hours from the commencement of the meal, but allow about 30 minutes for administration and initial cannulation)

Each test will be conducted seven days apart to allow a 'wash-out' between each testing period.

Intervention code [1]

Diagnosis / Prognosis

Comparator / control treatment

As described above, there is no separate control group. Each person acts as their own control. The glucose test is the standard baseline currently used for diagnosis/monitoring

Control group

Active

Outcomes

Primary outcome [1]

Inter-and intra- individual variability of the plasma glucose assessed by pharmacokinetic parameters (e.g. AUC, time to maximum concentration, maximum concentration and half-life of the response curve)

Timepoint [1]

Sampling will occur at baseline then 30 min, 60 min, 120 min, and 180 min. Timing will commence when the participants commence meal consumption.

Primary outcome [2]

Inter-and intra- individual variability of the plasma insulin concentrations assessed by pharmacokinetic parameters (e.g. AUC, time to maximum concentration, maximum concentration and half-life of the response curve)

Timepoint [2]

Sampling will occur at baseline, 30 min, 60min, 120 min and 180 min. Timing will commence when the participant commences meal consumption.

Primary outcome [3]

Inter-and intra- individual variability of the plasma c-peptide levels assessed by pharmacokinetic parameters (e.g. AUC, time to maximum concentration, maximum concentration and half-life of the response curve)

Timepoint [3]

Sampling will occur at baseline, 30 min, 60min, 120 min and 180 min. Timing will commence when the participant commences meal consumption.

Secondary outcome [1]

There are no secondary outcomes except as described in statistical analysis

Timepoint [1]

N/A

Eligibility

Key inclusion criteria

NZ European

Healthy with no recent injuries (acute or chronic)

Currently consuming at least 150g carbohydrate per day for at least two weeks prior to the testing period.

Able to provide informed consent and adhere to research protocols.

Minimum age

20 Years

Maximum age

45 Years

Sex

Males

Can healthy volunteers participate?

Yes

Key exclusion criteria

Body mass index less than 18 kg/m2

Any food allergy or intolerance, including, but not limited to coeliac disease, lactose intolerance, and nut or egg allergies.

An unwillingness to consume a variety of foods, even in the absence of food allergies or intolerances.

Anyone with a medical condition (illness or injury) that may cause: increased bleeding, poor circulation, poor venous access, or unstable health.

Anyone with a known gastrointestinal disorder, including, but not limited to, inflammatory bowel disease, irritable bowel disease, chronic constipation or diarrhoea, or recent (within 4 weeks) gastrointestinal infection.

Anyone taking medication that can affect blood glucose, phosphate, or lipid levels including (but not limited to): insulin; sulphonylurea medications; metformin; statins; or calcium.

A history of cancer (excluding non-melanoma skin cancers).

Current smokers / vapers or those recently discontinued smoking/vaping (previous three months).

Study design

Purpose of the study

Diagnosis

Allocation to intervention

Randomised controlled trial

Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)

Allocation not concealed

Methods used to generate the sequence in which subjects will be randomised (sequence generation)

Simple randomisation using Excel random generators

Masking / blinding

Open (masking not used)

Who is / are masked / blinded?

Intervention assignment

Crossover

Other design features

Phase

Not Applicable

Type of endpoint/s

Pharmacokinetics / pharmacodynamics

Statistical methods / analysis

The OGTT with insulin assay will be stratified according to World Health Organisation standards for glucose response and Kraft pattern algorithms as according to Crofts et al. (2016).

The mixed meal tolerance tests will have their c-peptide, insulin and glucose responses drawn for each individual. Insulin and glucose responses will be compared for area-under-the-curve and pharmacokinetic parameters including time to maximum concentration, maximum concentration and half-life of the response curve. Comparisons will be between participants, across the different meals.

A sub-study will perform secondary analysis on the collected data to compare the pharmacokinetic parameters of the insulin to the c-peptide response curves from each individual meal. Curves will be compared using Pearson's correlations

Recruitment

Recruitment status

Not yet recruiting

Date of first participant enrolment

Anticipated

1/10/2020

Actual

Date of last participant enrolment

Anticipated

8/10/2020

Actual

Date of last data collection

Anticipated

30/10/2020

Actual

Sample size

Target

Accrual to date

Final

Recruitment outside Australia

Country [1]

New Zealand

State/province [1]

Auckland

Funding & Sponsors

Funding source category [1]

University

Name [1]

Auckland University of Technology

Address [1]

90 Akoranga Drive,
Northcote 0627
Auckland

Country [1]

New Zealand

Primary sponsor type

University

Name

Auckland Universityof technology

Address

90 Akoranga Drive,
Northcote 0627
Auckland

Country

New Zealand

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Submitted, not yet approved

Ethics committee name [1]

Northern B Health and Disability Ethics Committees

Ethics committee address [1]

Ministry of Health
Health and Disability Ethics Committees
PO Box 5013
Wellington 6140

Ethics committee country [1]

New Zealand

Date submitted for ethics approval [1]

11/03/2020

Approval date [1]

Ethics approval number [1]

20/NTB/52

Ethics committee name [2]

Auckland University of Technology Ethics Committee

Ethics committee address [2]

Auckland University of Technology
46 Wakefield Street, Auckland 1010
Private Bag 92006, Auckland 1142

Ethics committee country [2]

New Zealand

Date submitted for ethics approval [2]

13/07/2020

Approval date [2]

Ethics approval number [2]

Summary

Brief summary

A comparison of mixed meals (smoothie compared to 'whole food') against the standard oral glucose tolerance test to investigate a) feasibility for use in assessing and monitoring metabolic response and b) use of c-peptide for assessing hyperinsulinaemia.  
Chronic hyperinsulinaemia associated with insulin resistance underpins many globally significant chronic diseases, including type 2 diabetes with resultant morbidity and premature mortality and economic burden. Although the relationship between elevated plasma glucose and /or insulin levels and chronic disease is accepted, there are mounting concerns about the methodologies used to diagnose these conditions.  The globally standardised oral glucose tolerance challenge, the baseline measure for both glucose and insulin response tests, is standardised so that every adult older than 20 years receives 75g glucose,  The fundamental flaw with this procedure is that glucose disposal rates vary depending on sex, lean body mass, physical activity and foods consumed during the previous 72 hours.  Further criticisms of the oral glucose challenge include that it does not reflect normal eating patterns, and the excessively high glucose dose.   It is hypothesised that a mixed meal tolerance test (a combination of protein, carbohydrate and fats) that is tailored to the participants’ gender, mass and activity status may provide a better platform from which to understand metabolic responses.  It may also provide a better platform from which to better understand metabolic responses following dietary interventions to manage metabolic health, such as a low-carbohydrate diet.   It is further hypothesised that c-peptide response patterns could be used as a proxy for insulin response patterns but comparative data is lacking.  
Recruiting 10 european males for a 3-way cross-over will collect sufficient data for this pilot.

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

Dr Catherine Crofts

Address

A-25
Auckland University of Technology (AUT)
Private Bag 92006
Auckland 1142 , New Zealand

Country

New Zealand

Phone

+64 9 921 9999

Fax

ccrofts@aut.ac.nz

Contact person for public queries

Name

Catherine Crofts

Address

A-25
Auckland University of Technology (AUT)
Private Bag 92006
Auckland 1142 , New Zealand

Country

New Zealand

Phone

+64 9 921 9999

Fax

ccrofts@aut.ac.nz

Contact person for scientific queries

Name

Catherine Crofts

Address

A-25
Auckland University of Technology (AUT)
Private Bag 92006
Auckland 1142 , New Zealand

Country

New Zealand

Phone

+64 9 921 9999

Fax

ccrofts@aut.ac.nz

Data sharing statement

Will individual participant data (IPD) for this trial be available (including data dictionaries)?

Yes

What data in particular will be shared?

Anthropometric data, glucose, insulin, c-peptide reponses

When will data be available (start and end dates)?

Starting January 2022; available for a minimum of ten years. (Following that, will be dependent on whether it has been accessed within that time.)

Available to whom?

researchers who provide a methodologically sound proposal, case-by-case basis at the discretion of Primary Sponsor

Available for what types of analyses?

only to achieve the aims in the approved proposal

How or where can data be obtained?

access subject to approvals by Principal Investigator ccrofts@aut.ac.nz

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.

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