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Trial registered on ANZCTR


Registration number
ACTRN12622001075774
Ethics application status
Approved
Date submitted
29/07/2022
Date registered
3/08/2022
Date last updated
29/11/2022
Date data sharing statement initially provided
3/08/2022
Type of registration
Retrospectively registered

Titles & IDs
Public title
Comparing the effects of almond and walnut butters on glucose and insulin levels after eating white bread, in a population at increased risk of diabetes.
Scientific title
Comparing the acute effects of almond and walnut butter on post-prandial glucose and insulin response in a population at increased risk of diabetes: A randomised controlled cross-over trial.
Secondary ID [1] 307677 0
None
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Type 2 diabetes 327215 0
Condition category
Condition code
Metabolic and Endocrine 324351 324351 0 0
Diabetes

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Intervention products: Nut butters (walnut and almond)

Whilst numerous studies have focused upon whole nuts, there are few studies which have examined the effects nut butters, such as almond or walnut, on postprandial glycaemic control in a population at increased risk of diabetes (>18yrs of age, waist circumference >88cm women, >102cm men)

This study is a three-arm randomised controlled cross-over study design:
Arm 1: 60g almond butter + 104g white bread (50g available carbohydrate)
Arm 2: 60g walnut butter + 104g white bread (50g available carbohydrate)
Arm 3: 104g white bread alone (control).

All eligible participants will be asked to attend three separate face to face testing visits to complete the three study arms (one arm per visit, in a randomly allocated order). All visits will be conducted by the Honours Student M. Noonan, in conjunction with the supervisors Professor Gary Williamson and Dr Margaret Murray. At each testing visit participants will have multiple finger prick blood samples taken over a 180-minute period after consuming either the control meal or intervention meals, in order to test postprandial glucose and insulin response.

Participants will be asked to fast from 9 pm the night before (>10 h fast) following a standardised dinner meal, and avoid nuts and nut-containing foods and strenuous physical activity for 24 hours before testing. They will also be asked to consume the test meals within 10 minutes.

A washout period of at least one week will occur between each testing visit.
Intervention code [1] 324153 0
Prevention
Comparator / control treatment
The control for this study is as follows:
Arm 3: 104g white bread alone (which provides 50g available Carbohydrate).
Control group
Active

Outcomes
Primary outcome [1] 332154 0
Postprandial blood glucose area under the curve (AUC).
Timepoint [1] 332154 0
Blood glucose will be measured at 10 and 5 minutes before commencement of eating to ascertain fasting glucose.
Postprandial measurements will be taken at: +15, +30, +45, +60, +90, +120, +150, +180 minutes after commencement of eating.
Primary outcome [2] 332155 0
Postprandial plasma insulin area under the curve (AUC)
Timepoint [2] 332155 0
A plasma sample will be collected in the fasting state, then at +30, +60, +90, +120, +150 and +180 minutes after commencing the meal , to measure plasma insulin.
Secondary outcome [1] 412393 0
Postprandial satiety, as measured by a visual analogue hunger scale and calculated as area under the curve (AUC)
Timepoint [1] 412393 0
The Hunger Scale satiety values will be collected at the following time intervals: fasting, and 60, 120 and 180 minutes after commencement of eating.

Eligibility
Key inclusion criteria
Individuals 18 years of age and above
A waist circumference measure greater than or equal to 88cm in women and 102cm in men
Able to consume nuts AND gluten containing products (pasta and white bread) with nil adverse effects
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
Current Smokers
Individuals with an Implanted Cardiac Defibrillator (ICD)
Consuming >14 standard drinks of alcohol per week
Females who are pregnant, trying to become pregnant or breastfeeding
Individuals who have been diagnosed with Diabetes or taking Diabetes medications

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 not concealed
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
A Latin Square randomisation method was used to randomly generate the order in which participants were allocated to receive each of the three treatment arms
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint/s
Statistical methods / analysis
The power calculation done for this study showed that with an alpha-value of 0.05 and for 80% power, a total of seven participants were needed to show a difference between groups. This was based upon the study by Crouch and Slater (Almond “appetizer” effect on glucose tolerance (GTT) results- JABFM, Nov 2016, 29(6), 759-766) and used postprandial area under the curve data for blood glucose, comparing a control with an almond intervention.

We will report means +/- standard deviations for baseline data (e.g. demographics, nut consumption and physical activity). Data pertaining to insulin, glucose and satiety will be reported as AUC. Within subjects ANOVA and paired T-tests will be used for examining differences.

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
23/05/2022
Date of last participant enrolment
Anticipated
2/09/2022
Actual
31/08/2022
Date of last data collection
Anticipated
30/09/2022
Actual
28/09/2022
Sample size
Target
10
Accrual to date
Final
8
Recruitment in Australia
Recruitment state(s)
VIC

Funding & Sponsors
Funding source category [1] 311947 0
University
Name [1] 311947 0
Monash University
Country [1] 311947 0
Australia
Primary sponsor type
University
Name
Monash Univeristy
Address
Department of Nutrition, Dietetics and Food. Monash Be Active Sleep Eat (BASE) facility, Level 1, 264 Ferntree Gully Road, Notting Hill, VIC 3168
Country
Australia
Secondary sponsor category [1] 313433 0
None
Name [1] 313433 0
Address [1] 313433 0
Country [1] 313433 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 311377 0
Monash University Human Research Ethics Committee (MUHREC)
Ethics committee address [1] 311377 0
Monash University, Wellington Road, Clayton, VIC 3800.
Ethics committee country [1] 311377 0
Australia
Date submitted for ethics approval [1] 311377 0
29/04/2022
Approval date [1] 311377 0
03/05/2022
Ethics approval number [1] 311377 0
32274

Summary
Brief summary
Diabetes is a progressive, chronic disease characterised by elevated blood glucose levels. Approximately two million Australians are currently at high risk of developing Type 2 Diabetes. There has been increased attention to the effects of individual food items and nutrients on the outcome of Type 2 Diabetes in recent times, including nuts. Regular nut consumption has been shown to improve glucose control and reduce the overall risk of Type 2 Diabetes.

The glycaemic response varies for different carbohydrates. In addition to the level of available carbohydrate in foods, the remaining composition of a food item can also influence the glycaemic response. Almonds have been shown to decrease blood glucose levels and increase satiety after eating. Walnuts contribute numerous positive health benefits including lowering cholesterol and reducing inflammation. Both walnuts and almonds contain high amounts of polyphenols.

The form in which nuts are consumed (butter vs whole nuts) may lead to differing metabolic responses. Whilst there are several acute feeding studies which have looked at the postprandial glucose and insulin responses of whole walnuts and almonds, very few have looked at almond or walnut butters, (despite widespread commercial availability of such products). The current study design hopes to provide answers to this research gap.

Significant outcomes of the research may include:
- Understanding the effects of almond and walnut butters on blood glucose and insulin levels
- Understanding the subjective satiety measures of almond and walnut butters

We hypothesise that consuming almond butter or walnut butter with white bread will lower the resulting glucose and insulin response, as compared to white bread alone.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 120886 0
Prof Gary Williamson
Address 120886 0
Nutrition, Dietetics and Food
Faculty of Medicine, Nursing and Health Sciences, Monash University
Be Active Sleep Eat Facility (BASE)
Level 1, 264 Ferntree Gully Road, Notting Hill, VIC 3168
Country 120886 0
Australia
Phone 120886 0
+61 399056649
Fax 120886 0
Email 120886 0
[email protected]
Contact person for public queries
Name 120887 0
Gary Williamson
Address 120887 0
Nutrition, Dietetics and Food
Faculty of Medicine, Nursing and Health Sciences, Monash University
Be Active Sleep Eat Facility (BASE)
Level 1, 264 Ferntree Gully Road, Notting Hill, VIC 3168
Country 120887 0
Australia
Phone 120887 0
+61 399056649
Fax 120887 0
Email 120887 0
[email protected]
Contact person for scientific queries
Name 120888 0
Gary Williamson
Address 120888 0
Nutrition, Dietetics and Food
Faculty of Medicine, Nursing and Health Sciences, Monash University
Be Active Sleep Eat Facility (BASE)
Level 1, 264 Ferntree Gully Road, Notting Hill, VIC 3168
Country 120888 0
Australia
Phone 120888 0
+61 399056649
Fax 120888 0
Email 120888 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment


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.