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Trial registered on ANZCTR


Registration number
ACTRN12616001306404
Ethics application status
Approved
Date submitted
2/03/2015
Date registered
19/09/2016
Date last updated
19/09/2016
Type of registration
Retrospectively registered

Titles & IDs
Public title
The Effect of Dairy on Insulin Sensitivity.
Scientific title
In participants who have not yet developed Type II Diabetes Mellitus, does consuming a high dairy diet (compared to a low dairy diet) affect insulin sensitivity?
Secondary ID [1] 286288 0
Nil known.
Universal Trial Number (UTN)
U1111-1167-7778
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Type II Diabetes 294370 0
Cardiovascular disease 300256 0
Condition category
Condition code
Metabolic and Endocrine 294684 294684 0 0
Diabetes
Cardiovascular 294685 294685 0 0
Other cardiovascular diseases

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
This study involves recruiting participants over 18 years of age to a 10 week, randomised crossover intervention.

Each participant will be exposed to two diets, lasting four weeks each; a high dairy diet, and a low dairy diet. These diets are separated by a two week period where the participants will resume their habitual diets.

Screening:

Participants are weighed, height is measured, and an oral glucose tolerance test is given to determine their glucose tolerance. Participants are also instructed to provide a 3 day weighed food record to this visit.

Arm 1

The high dairy diet consists of consuming 4-6 serves of dairy per day, with at least two of these serves being yoghurt. There are no restrictions on the fat content of the dairy, and dairy products are not supplied by the investigators. The participants are compensated for their grocery expenses.


Arm 2
The low dairy diet requires participants to eat just 0.5 serves per day.

After each four week period, participants will undergo two insulin sensitivity tests, and a pulse wave velocity test.

The first insulin sensitivity test is the Low Dose Insulin and Glucose Infusion Test, or LDIGIT. It involves infusing a small amount of insulin (25mU/kg body weight/hr), and glucose (4mg/kg/min) into a fasting patient, and taking blood samples at regular time points to assess serum glucose, insulin and c-peptide levels.

The second test is the hyperglycaemic clamp, involving the infusion of glucose into a participant, where the serum glucose level will be held at 10mmol/L, and blood samples will be taken at regular time points to assess serum glucose and insulin levels, and c-peptide response.

Finally, pulse wave velocity will be assessed in the participant to determine an individual's risk of developing cardiovascular disease after consuming high and low dairy diets. A blood pressure cuff is placed on the upper thigh while the participant lies in the supine position, and a pulse probe is placed on the carotid pulse site. The cuff automatically inflates, and a computer records and calculates the resulting pulse wave velocity.

To ensure compliance to the intervention, participants meet with the investigator halfway through each diet, and weighed food diaries are prepared. The investigator then assesses the diaries, and makes suggestions to aid the participants with compliance. Participants are required to remain weight stable during this intervention, and so it is necessary for them to remove foods that have similar energy content to the extra dairy that they are adding into Arm 1 of the study. In Arm 2 of the study, participants are required to substitute in foods with similar energy content to account for the dairy removed from the diet. A guide is provided for both arms of the study for participants to refer to, and also includes suggestions for including more dairy into the diet.

A serve of dairy is defined as

* 1 cup or 250ml of milk (fresh, UHT, reconstituted powdered milk )
* 40g, equivalent to 2 slices, or 4x3x2cm cube of hard cheese (eg cheddar)
* 1/2cup or 120g ricotta cheese
* 3/4 cup or 200g of yoghurt
Intervention code [1] 291316 0
Prevention
Intervention code [2] 295890 0
Treatment: Other
Comparator / control treatment
Low Dairy Diet: Participants are restricted to just 0.5 serves of dairy/day for four weeks.
Control group
Active

Outcomes
Primary outcome [1] 294445 0
Insulin sensitivity. calculated by using serum glucose (Konelab analysis) and Insulin (Human Insulin ELISA) results from both insulin sensitivity tests.'
Timepoint [1] 294445 0
4 weeks and 10 weeks into the study
Secondary outcome [1] 313338 0
Pulse wave velocity - a blood pressure cuff is placed on the right thigh of the participant, and a pulse probe is placed on the carotid pulse site, on the neck, After obtaining a suitable pulse, the computer software will inflate the cuff, and obtain a pulse wave velocity is obtained in metres/second. This reading is performed three times to obtain an average.
Timepoint [1] 313338 0
At 4 weeks and 10 weeks into the study.

Eligibility
Key inclusion criteria
Normal weight, overweight and obese individuals
Individuals with Normal and Impaired glucose tolerance
Weight stable condition: participant change in body weight in the previous 3 months is less than 3kg.
Minimum age
18 Years
Maximum age
No limit
Gender
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Participants already suffering from type II diabetes,
Participants who smoke tobacco
Participants with active gastrointestinal or eating disorders
Participants with adverse responses to dairy products
Participants using over the counter pharmaceuticals to counteract their obese/overweight condition.

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)
Potential participants come to a clinical trial facility fasting (after they have read the information sheet, and have agreed to participate), where they are weighed, have their height measured, and are subjected to an oral glucose tolerance test to determine their glucose tolerance. Before this test, a finger prick is performed, and a blood glucose reading is taken. After consuming a 75g dose of glucose, another finger prick blood sample is taken 2 hours after consuming the 75g glucose dose.

The participant is enrolled into the study after signing the consent form (obtained prior to performing the oral glucose tolerance test, where they once again read the information sheet), and a diet is assigned to them by flipping a coin. A guide describing how to remove or incorporate diary into their diets is given to them, and a verbal explanation of how many serves they are required to eat in each diet. A start date for their diet is given, and in the next few days, a check-up appointment is scheduled for two weeks into the diet.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
3. Simple randomisation by coin flip.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



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

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
SA
Recruitment postcode(s) [1] 9298 0
5000 - Adelaide

Funding & Sponsors
Funding source category [1] 290852 0
Self funded/Unfunded
Name [1] 290852 0
Peter Clifton
Address [1] 290852 0
Level 5 room P5-16 Playford Building University of South Australia
GPO Box 2471 Adelaide SA 5001 Australia

Country [1] 290852 0
Australia
Primary sponsor type
Individual
Name
Peter Clifton
Address
Level 5 room P5-16 Playford Building University of South Australia
GPO Box 2471 Adelaide SA 5001 Australia
Country
Australia
Secondary sponsor category [1] 289542 0
Individual
Name [1] 289542 0
Jennifer Keogh
Address [1] 289542 0
P1-23 Playford Building City East Campus
Postal address: GPO Box 2471 Adelaide SA 5000 IPC CEA 19

Country [1] 289542 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 292468 0
Research Ethics, Compliance and Integrity Research Branch, The University of Adelaide
Ethics committee address [1] 292468 0
Level 7, 115 Grenfell St The University of Adelaide, SA, AUSTRALIA 5005
Ethics committee country [1] 292468 0
Australia
Date submitted for ethics approval [1] 292468 0
04/06/2014
Approval date [1] 292468 0
11/09/2014
Ethics approval number [1] 292468 0
H-2014-112

Summary
Brief summary
We are investigating how a high diary diet (compared to a low dairy diet) will affect insulin sensitivity in normal weight, and overweight/obese people with normal/impaired glucose tolerance.

There is evidence that dairy may affect insulin sensitivity, but currently the studies that perform dairy interventions in a diet are conflicted. There is therefore a need to design and perform dairy study that may help argue the case for our population eating more dairy in order to prevent developing type II diabetes.

Hypothesis: eating higher amounts of dairy each day for four weeks will improve insulin sensitivity.
Trial website
Trial related presentations / publications
Public notes
Attachments [1] 336 336 0 0

Contacts
Principal investigator
Name 55434 0
Mr Jordan Peters
Address 55434 0
The University of Adelaide
Eleanor Harrald Building
Level 6, Room 6-12
Frome Road
Adelaide
SA
5000
Country 55434 0
Australia
Phone 55434 0
+61 8 8222 5073
Fax 55434 0
Email 55434 0
jordan.peters@adelaide.edu.au
Contact person for public queries
Name 55435 0
Mr Jordan Peters
Address 55435 0
The University of Adelaide
Eleanor Harrald Building
Level 6, Room 6-12
Frome Road
Adelaide
SA
5000
Country 55435 0
Australia
Phone 55435 0
+61 8 8222 5073
Fax 55435 0
Email 55435 0
jordan.peters@adelaide.edu.au
Contact person for scientific queries
Name 55436 0
Mr Jordan Peters
Address 55436 0
The University of Adelaide
Eleanor Harrald Building
Level 6, Room 6-12
Frome Road
Adelaide
SA
5000
Country 55436 0
Australia
Phone 55436 0
+61 8 8222 5073
Fax 55436 0
Email 55436 0
jordan.peters@adelaide.edu.au

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary