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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
Relationships between oral and gastrointestinal sensitivities in response to fat and protein, and body mass index (BMI).
Scientific title
Relationships between antropyloroduodenal motility, gut hormone release, appetite and energy intake responses, and oral taste sensitivity, to fat and protein in male subjects with a range of body mass index (BMI).
Secondary ID [1] 281115 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Nutrition 287276 0
Gastrointestinal motor and hormonal function 287277 0
Oral cavity taste receptor sensitivity 287278 0
Condition category
Condition code
Diet and Nutrition 287602 287602 0 0
Other diet and nutrition disorders
Oral and Gastrointestinal 287603 287603 0 0
Normal oral and gastrointestinal development and function

Study type
Description of intervention(s) / exposure
The study requires 4 study visits, seperated by at least 3 days. Prior to each of the 4 study days, subjects will be provided with a McCains meat lasagne (400g, frozen) to consume for dinner the night before the study. Subjects will be asked to fast after this until arriving in the department.

On study days 1 and 2, subjects will recieve, in randomised, double-blinded fashion, a single 60 minute intraduodenal infusion at 4mL/min of either:
a) 3.0 kcal/min (Whey Protein Hydrolysate)
b) 3.0 kcal/min (10% Intralipid)

Appetite sensation questionnaires in the form of a Visual Analogue Scale (VAS) will be administered and blood samples taken at t=-10 (prior to commencement of infusion- baseline), 0 (beginning of infusion) and throughout the infusion at t=15,30,45 and 60 min.

A buffet meal will be provided at the end of infusion. The participant has 30 minutes to eat until comfortably full. The buffet meal consists of 300ml orange juice, 600ml water, 375ml iced coffee, 4 slices white bread, 4 slices brown bread, 100g deli leg ham, 100g virginian chicken, 4 slices cheese, 100g tomato, 100g cucumber, 100g lettuce, 2 portions mayonnaise, 2 portions margarine, 1 medium apple, 1 medium banana, 200g chocolate custard, 150g fruit salad, 200g strawberry yoghurt, and a 14g milky way chocolate bar. At t=90 min a final blood sample will be taken.

Each volunteer will receive one of the two infusion solutions on two of four study days. Each infusion visit will be separated by no less than 3 days. Each infusion visit will last approximately 3-6 hours.

On the remaining two study days (study visits 3 and 4) the volunteer will complete an oral sensitivity visit to establish at threshold concentrations at which oral cavity taste receptors are sensitive to:
a) Oleic acid (fat)
b) Mono-sodium glutamate (protein)

Each oral sensitivity study day consists of an oral detection threshold task and a taste preference task, with the protein day also including a discrimination task. Each oral sensitivity visit will last approximately 2-3 hours. Subjects will be provided a meal at completion of the visit, which will not be assessed.
Intervention code [1] 285572 0
Treatment: Other
Comparator / control treatment
Lipid (infusion visit of 10% intralipid and oral sensitivity visit of oleic acid) will be used as an active control as the relationship between oral sensitivity and small intestinal sensitivity to lipid has previously been established.
Control group

Primary outcome [1] 287862 0
Antropyloroduodenal (APD) Motility; specifically antropyloroduodenal pressures, number of antral, duodenal and isolated pyloric pressure waves, and basal pyloric pressure; assessed by high-resolution small intestinal manometry in response to lipid and protein.
Timepoint [1] 287862 0
On study visits 1 and 2, at t= -15 until 0, a baseline of the antropyloroduodenal (APD) motility is recorded.

Infusion starts at t=0 until t=60 minutes. APD motility is assessed continuously for the duration of the infusion (t=0-60 minutes).

Subject is extubated at t=60 minutes.
Primary outcome [2] 287866 0
Concentrations of plasma amino acids, glucose, insulin, and gut hormones (e.g. CCK, PYY, GLP-1, GIP, NPW and ghrelin).

Concentrations will be assessed by Enzyme-Linked Immunosorbent Assay (ELISA)/radioimmunoassay (RIA) from the blood samples taken.
Timepoint [2] 287866 0
On study visits 1 and 2, at t= -15 the subject is cannulated and a baseline blood sample taken. Further blood samples are taken at t= 0, 15, 30, 45, 60, & 90 minutes on intraduodenal infusion days only.
Primary outcome [3] 287876 0
Oral sensitivity to oleic acid and glutamate as determined by a detection threshold task and a taste preference task, using alternate forced-choice procedures.
Timepoint [3] 287876 0
On study visits 3 and 4, oral oleic acid and glutamate sensitivity will be examined (on randomised seperate study days) using oral taste threhold determination by 3-alternate forced-choice procedure, and oral taste preference determination by 2-alternate forced-choice procedure.
Secondary outcome [1] 298956 0
Macronutrient and total energy intake at the buffet meal will be analysed using the Foodworks software program.
Timepoint [1] 298956 0
On study visits 1 and 2, a buffet meal will be presented at the end of the infusion and after extubation (t=60). The subject will be allowed to freely consume food for 30 minutes until comfortably full (until t=90).
Secondary outcome [2] 298957 0
Appetite sensations using a Visual Analogue Scale (VAS) (nausea, bloating, hunger, fullness, desire to eat, amount of food desired to eat).
Timepoint [2] 298957 0
On study visits 1 and 2, VAS questionnaires are given at t= -15, 0, 15, 30, 45, 60, & 90 minutes.
Secondary outcome [3] 298996 0
Habitual macronutrient and total energy intake will be analysed using the Foodworks software program.
Timepoint [3] 298996 0
Prior to study visit 1, subjects will be asked to complete a 3 day food diary, including 2 week days and 1 weekend day.
On a randomised tasting day (study visit 3 or 4) subjects will be asked to undertake a 24 hour dietary recall interview.

Key inclusion criteria
Males with a BMI between 18-35 kg/m2.

Weight stable (<5% fluctuation in body weight in previous 3 months).
Minimum age
18 Years
Maximum age
60 Years
Can healthy volunteers participate?
Key exclusion criteria
Significant gastrointestinal symptoms, disease, or surgery

Use of prescribed or non-prescribed medications (including vitamins and herbal supplements) which may effect energy metabolism, gastrointestinal function, body weight, or appetite (eg. domperidone and cisapride, anticholinergic drugs (eg. atropine), metoclopramide, erythromycin, hyoscine, orlistat, green tea extracts, astragalus, St. johns wort etc.)

Lactose intolerant or other food allergies (particularly MSG); intolerance or allergy to paracetamol

Current, recurring or chronic rhinitis

Current gallbladder or pancreatic disease; diabetes mellitus; epilepsy; cardiovascular or respiratory diseases; any other illnesses as assessed by the investigator (including chronic illnesses not explicitly listed above)

Individuals with low ferritin levels or who have donated blood in the 12 weeks prior to taking part in the study

Individuals with blood glucose and/or glycated haemoglobin outside the normal ranges.

High performance athletes

Current intake of >2 standard drinks on >5 days per week

Current smokers of cigarettes/cigars/marijuana

Current intake of any illicit substance

Experience claustrophobia in confined spaces

Unable to tolerate nasogastrointestinal tube, or to comprehend study protocol

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Volunteers are asked to visit the clinic for a 30 minute screening visit. A screening questionnaire and three factor eating questionnaire are answered by the volunteer, and a blood sample taken for determination of ferritin levels. Eligibility is determined based on the inclusion/exclusion criteria. A signed informed consent form is obtained and study dates are established. Eligible volunteers are assigned a subject number and randomised into a treatment for each infusion study visit and each oral sensitivity visit using a randomisation table created on an excel spreadsheet. Randomisation involves contacting the holder of the randomisation table (study assistant) to inform them of the subjects details and study dates. The unblinded study assistant is therefore responsible for allocating a random treatment to the subject and preparing the solution for infusion on each study day.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
The randomisation table was created using Microsoft Office Excel.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Due to the nature (taste, texture) of the solutions used at the oral sensitivity visits, volunteers and researchers are not able to be blinded. Thus, only infusion visits are blinded for both researcher and volunteer.
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] 285906 0
Government body
Name [1] 285906 0
National Health and Medical Research Council Grant 627118
Address [1] 285906 0
Level 1 16 Marcus Clarke Street
Canberra ACT 2601
Country [1] 285906 0
Primary sponsor type
Dr Natalie Luscombe-Marsh
Level 6 Eleanor Harrald Building,
Frome Road,
Adelaide, SA 5000
Secondary sponsor category [1] 284728 0
Name [1] 284728 0
University of Adelaide
Address [1] 284728 0
North Terrace
Adelaide, SA 5005
Country [1] 284728 0

Ethics approval
Ethics application status
Ethics committee name [1] 287932 0
Royal Adelaide Hospital Research Ethics Committee
Ethics committee address [1] 287932 0
Level 3, Hanson Institute, North Terrace
Adelaide, South Australia, 5000
Ethics committee country [1] 287932 0
Date submitted for ethics approval [1] 287932 0
Approval date [1] 287932 0
Ethics approval number [1] 287932 0

Brief summary
This study has been designed to investigate how isocaloric loads of protein (whey protein hydolysate), or fat (intralipid (10%)) differentially affect gastrointestinal motility, gastrointestinal hormone release, and appetite sensations in male individuals with a range of BMI (between 18-35 kg/m2). Further, the sensitivity of these individuals to the presence of protein or fat in the oral cavity will be measured and related to their gastrointestinal responsiveness to protein and fat, respectively. Relationships between BMI, gastrointestinal and oral sensitivities and habitual macronutrient and energy intake will also be assessed.

Thus, the specific aims of this study are to determine:

the effects of small intestinal lipid and protein, infused at a rate comparable to that of average gastric emptying, on antropyloroduodenal motility, gut hormone release, appetite and energy intake across a range of BMI

oral fatty acid, and glutamate, sensitivity across a range of BMI

And to assess the relationships between:
oral sensitivity to oleic acid and glutamate and gastrointestinal responsiveness to fat and protein, respectively

energy intake with oral taste sensitivity and/or gastrointestinal responsiveness, to fat and protein

BMI with oral taste thresholds, and gastrointestinal sensitivity, to fat and protein

habitual intake, BMI and oral and/or gastrointestinal sensitivity to fat and protein.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 34634 0
Dr Natalie Luscombe-Marsh
Address 34634 0
Level 6, Eleanor Harrald Building, Frome Road, Adelaide, SA 5000
Country 34634 0
Phone 34634 0
+61 8 8305 0605
Fax 34634 0
Email 34634 0
Contact person for public queries
Name 17881 0
Dr Dr Natalie Luscombe-Marsh
Address 17881 0
Level 6, Eleanor Harrald Building,
Frome Road,
Adelaide, SA 5000
Country 17881 0
Phone 17881 0
+61 8 8305 0605
Fax 17881 0
Email 17881 0
Contact person for scientific queries
Name 8809 0
Dr Dr Natalie Luscombe-Marsh
Address 8809 0
Level 6, Eleanor Harrald Building,
Frome Road,
Adelaide, SA 5000
Country 8809 0
Phone 8809 0
+61 8 8305 0605
Fax 8809 0
Email 8809 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