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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Retrospectively registered

Titles & IDs
Public title
The chronic effects of whey protein isolate on metabolic syndrome risk factors in overweight and obese individuals
Scientific title
The chronic effects of whey protein isolate on metabolic syndrome risk factors in overweight and obese individuals
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Metabolic risk factors in overweight and obese individuals 4418 0
Condition category
Condition code
Diet and Nutrition 4682 4682 0 0

Study type
Description of intervention(s) / exposure
Chronic, randomized, parallel design study with 3 intervention groups where subjects consume 30g of either whey protein isolate, casein protein or glucose (control) in powder form mixed with 250ml water twice a day over a 12 week period while maintaining their usual diet and exercise regime
Intervention code [1] 4160 0
Other interventions
Comparator / control treatment
Placebo is 30g glucose (same dose as whey & casein) in powder form mixed with 250ml water for the control group twice a day
Control group

Primary outcome [1] 5545 0
Improved blood lipid, lipoprotein profile, glucose tolerance and insulin response
Timepoint [1] 5545 0
Blood samples taken a 0, 6 and 12 weeks
Primary outcome [2] 5546 0
Improved blood pressure after 12 weeks. Blood pressure will be measured by research assistant using a Systolic blood pressure (SBP), diastolic blood pressure (DBP) measured on the left arm of participants with an automated sphygmomanometer (Dinamap ProCare). Subjects rested in a supine position before and during measurements.
Timepoint [2] 5546 0
Measured at 0, 6 and 12 weeks
Primary outcome [3] 5547 0
Reduced body fat mass & preserved or increased muscle mass
Timepoint [3] 5547 0
Measured by Dual-energy X-ray Absorptiometry (DEXA) at 0 and 12 weeks plus
Weight and anthropometric measures taken at 0, 6 and 12 weeks
Secondary outcome [1] 9342 0
Improved vascular endothelium function via Sphygmocor pulse wave analysis (PWA)
Timepoint [1] 9342 0
PWA readings at 0, 6 and 12 weeks

Key inclusion criteria
Body Mass Index (BMI) between 25-35kg/m2
Not on regular medications
Have low dairy intake (<1-2 serves/day)
Less than 1 alcoholic drink/day for women, 2 for men
Weight stable
No major diseases or disorders
Minimum age
18 Years
Maximum age
65 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
On regular medications, especially those affecting blood pressure, thryoid, blood lipids
High consumption of dairy or alcohol
Taking regular supplements, vitamins, herbal remedies
On a weight loss regime

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
numbered containers
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation by using a randomisation table from a statistic book
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?

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

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 4612 0
Commercial sector/Industry
Name [1] 4612 0
Dairy Australia
Address [1] 4612 0
Locked Bag 104 Flinders Lane
Victoria 8009
Country [1] 4612 0
Primary sponsor type
Commercial sector/Industry
Dairy Australia
Locked Bag 104 Flinders Lane
Victoria 8009
Secondary sponsor category [1] 4330 0
Commercial sector/Industry
Name [1] 4330 0
Dairy Australia
Address [1] 4330 0
Locked Bag 104 Flinders Lane
Victoria 8009
Country [1] 4330 0

Ethics approval
Ethics application status
Ethics committee name [1] 6656 0
Curtin University Human Ethics Committee
Ethics committee address [1] 6656 0
GPO Box U1987
Perth WA
Ethics committee country [1] 6656 0
Date submitted for ethics approval [1] 6656 0
Approval date [1] 6656 0
Ethics approval number [1] 6656 0
HR 149/2007

Brief summary
The prevalence of overweight/obesity is currently exploding with over 60% of Australian adults in this category, leading to a rapid increase in diabetes, hypertension, and cardiovascular disease (CVD). Increased dairy consumption has been demonstrated to significantly benefit weight loss. Initially, it was thought that diary calcium was the reason for these health benefits, but recent studies have shown that this is not the case. Attention is now focused to other dairy components, such as dairy proteins. Although there is no clinical evidence in humans to support this, exciting new research from animal studies have shown that dairy whey-protein isolate (WPI) can reduce body weight, lower plasma lipids, improve, blood pressure and insulin action. There is an urgent need to provide the scientific evidence to clarify whether the protein component is responsible for the observed association between dairy consumption and body weight. Therefore the aim of this study was to investigate whether prolonged, chronic consumption of WPI will promote weight loss and improve CVD risk factors in the overweight/obese. The hypothesis for this study was that consumption of dairy whey-protein isolate will improve cardiovascular health/metabolic syndrome by reducing plasma lipids, blood pressure, arterial stiffness, inflammatory markers, enhanced glucose tolerance, endothelial function and insulin action.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 29350 0
Address 29350 0
Country 29350 0
Phone 29350 0
Fax 29350 0
Email 29350 0
Contact person for public queries
Name 12597 0
Assoc Prof Sebely Pal
Address 12597 0
School of Public Health
Curtin University
GPO Box U1987
Perth WA 6845
Country 12597 0
Phone 12597 0
+61 8 9266 4755
Fax 12597 0
+61 8 9266 2958
Email 12597 0
Contact person for scientific queries
Name 3525 0
Assoc Prof Sebely Pal
Address 3525 0
School of Public Health
Curtin University
GPO Box U1987
Perth WA 6845
Country 3525 0
Phone 3525 0
+61 8 9266 4755
Fax 3525 0
+61 8 9266 2958
Email 3525 0

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