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Trial registered on ANZCTR

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

Titles & IDs
Public title
Determination of nutritional quality of proteins for human nutrition
Scientific title
Evaluation of nutritional quality of dietary protein sources for human nutrition in human ileostomates
Secondary ID [1] 295224 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Protein digestion 308381 0
Condition category
Condition code
Oral and Gastrointestinal 307375 307375 0 0
Normal oral and gastrointestinal development and function

Study type
Description of intervention(s) / exposure
Determination of the ileal digestibility of dietary proteins in adults with ileostomies.
The methods to be used strictly follow recommendations of the FAO Working Group (FAO, 2014).
A total of eight test foods, human foods that are routinely consumed, will be evaluated. These foods range from purified protein sources (bovine collagen) to processed foods (All Bran cereal, toasted wheat bread), legumes (black beans, chickpeas, pigeon peas) and grains/nuts (sorghum, roasted peanuts). Each participant will also receive a protein-free diet as described below allow the content of their endogenous (non-dietary) secretions to be determined.
Sixteen men and women with normally functioning ileostomies will participate in the study. Overall, participants will receive four of the eight protein sources as well as a protein-free diet, receiving single meal of each protein source on two days with digesta collection both days as described below. Thus each protein source will be evaluated over two days in a total of 8 participants.
The protein sources that each participant will receive and the order in which they will receive them will be according to an incomplete Latin Square design.
For each test day, participants will fast overnight (14 hours) then at 8:30am, they will attach a new ostomy bag and consume one test meal containing their corresponding protein source (25 g of protein) within 30 minutes. They will have the option of coming into our facilities to consume their test meal or we will deliver the test food (and collection containers) to them. The collection period will continue for nine hours (8:30am – 5:30pm). The ostomy contents from the ostomy bags will be transferred every 2-3 hours to a container. We will send a text message to each participant when it is time to empty their ostomy bags. They will be asked questions at the end of the day including about what they ate during the day (to test for compliance) and when they emptied their ostomy bag.
There will be at least 3 days between study days, during which the participants will consume their normal diet.
The digesta samples will be used to determine the true ileal digestibility of amino acids. The equivalent values are also being determined in the pig following consumption of the same protein sources (tested as part of this study).
The digestibility of the foods will be compared between the humans and the pigs. A linear regression model will be developed to allow the prediction of human true ileal amino acid digestibility based on similar pig digestibility values. This will also allow us to confirm the suitability of the pig as a model for the human for determination of the nutritional quality of protein sources.
Intervention code [1] 301562 0
Other interventions
Comparator / control treatment
The digestibility of each food will be compared between the humans and the pigs.
Control group

Primary outcome [1] 306346 0
Data on the true ileal amino acid digestibility of eight protein sources in the human will be obtained, and compared with equivalent data obtained in the pig using regression analysis.
The instrument used will be digesta from the final part of the small intestine (the ileum) collected through the participants' ileostomies. The difference in the content of amino acids in the digesta from that consumed in the test meal will allow us to determine the protein/amino acid digestibility of the protein source, which gives an indication of the availability of the protein in the protein source.
Timepoint [1] 306346 0
Digesta will be collected through the ileostomies by the participants for a period of 9 hours after the test diet has been consumed. They will empty their ostomy bags (collecting the contents every 2-3 hours during this 9-hour period. However, all of the digesta from the same day will be pooled to provide one sample per day.
Secondary outcome [1] 348239 0
The proportion of the consumed protein that passes through the digestive tract (mouth to end of terminal ileum) over the 9-hour sampling period will be determined.
Timepoint [1] 348239 0
The participants will collect the digesta from their ostomy bags every 2-3 hours over a 9-hour period. This digesta will be pooled to give one sample per participant per protein source per 9-hour collection period.
Analysis of digesta collected over 9 hours, following the consumption of the test diet containing the protein sources.

Key inclusion criteria
Participants who have a well-established ileostomy with not more than 10cm of the terminal ileum removed and who are in good general health.
Minimum age
18 Years
Maximum age
70 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
• being pregnant or breastfeeding in the last 12 months, or planning to become pregnant during the study
• smoking cigarettes or recreational drugs (e.g. cannabis, amphetamine)
• consuming more than two standard drinks a day (eg. two glasses of wine or one pint of beer or more than two shots (60 mL) of spirits)
• being a vegetarian or vegan
• having an allergy to dairy products, gluten intolerance or allergy to proteins
• currently taking protein supplements and not willing to stop using these during the study
• being on a controlled diet or dietary weight loss regimen during the two weeks prior to the start of this study and/or during the study
• having a Body Mass Index (BMI) less than 18 or more than 27 kg/m2
• having renal impairment or diabetes

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
As the participants are likely to recognise some, if not all, of the proteins to be evaluated, allocation is not concealed.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
The sequence that the participants will receive each protein source (and which sources each will receive) has been randomly determined, according to a Latin Square design (incomplete). The participants are then randomly assigned to this Latin Square.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Incomplete Latin Square, with participants assigned randomly to the Latin Square.
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
Number of participants:
1. We have access to 4 historical results (true ileal AA digestibility in human and growing pig; Deglaire, 2008). Data analysis will be conducted with the eight samples in the present study, an additional study being conducted in the Netherlands (with 2 additional protein sources) and including the 4 historical results (14 samples). If the historical results are identified as outliers, they will be removed from the analysis. With n=10 protein sources (this study and that being conducted in the Netherlands), the t-value is 2.31 x standard error (SE) and the 95% CI around the estimates for slope and intercept is 0.73 standard deviations versus 2.18 and 0.58 with n=14 samples, respectively.
2.We are following the procedure developed by Moughan et al (2005), as per FAO (2014), which calls for 8 participants to receive each protein-based food. To shorten the trial for the participants, we intend that each participant should receive 4 of the foods, which means we will need 16 participants.

Statistical methods:
Statistical analyses will be performed using the software SAS (SAS/STAT version 9.4; SAS Institute Inc., Cary, NC, USA). Several statistical analyses will be conducted on the results obtained during the study.
The true ileal amino acid digestibility for the protein sources will be compared between the pig and the human. Firstly we will determine whether the same differences (or patterns) among proteins are obtained within each species (human and pig). To compare true ileal digestibility of each amino acid (i.e. response variable) of the different protein sources in the pig a MIXED model will be used. The most appropriate covariance structure of the mixed model for each response variable will be selected after fitting the models by the Restricted Maximum Likelihood method and comparing them using the log-likelihood ratio test. The model diagnostics for each response variable will be tested using the ODS GRAPHICS procedures of SAS before comparing the means. When the F-value of the analysis of variance is found to be significant (P<0.05), the means will be compared using adjusted Tukey tests. The same procedure described above will be used for the results obtained from the pig study. Thus we will identify if the same differences (or patterns) among proteins are obtained between both species.
A regression analysis will be conducted to determine the linear relationship between the true ileal amino acid digestibility in pigs and their human counterparts using the PROC REG of SAS. Thus we will generate the linear regression model.

Recruitment status
Not yet recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 10569 0
New Zealand
State/province [1] 10569 0

Funding & Sponsors
Funding source category [1] 299815 0
Commercial sector/Industry
Name [1] 299815 0
Global Dairy Platform
Address [1] 299815 0
10255 West Higgins Road, Suite 820
Rosemont, IL, 60018-5616
Country [1] 299815 0
United States of America
Primary sponsor type
Riddet Institute, Massey University
Riddet Institute
Massey University
Private Bag 11222
Palmerston North 4474
New Zealand
Secondary sponsor category [1] 299834 0
Name [1] 299834 0
Address [1] 299834 0
Country [1] 299834 0
Other collaborator category [1] 280211 0
Name [1] 280211 0
Wageningen University & Research
Address [1] 280211 0
Wageningen University & Research
Animal Nutrition Group
Department of Animal Sciences
Wageningen University
PO Box 338
6700 AH Wageningen
Country [1] 280211 0

Ethics approval
Ethics application status
Ethics committee name [1] 300694 0
HEC Southern A Application
Ethics committee address [1] 300694 0
Research Ethics Office
Courtyard Complex, Room 1.23
Manawatu Campus
Massey University/Te Kunenga ki Purehuroa
Private Bag 11222
Palmerston North 4410
Ethics committee country [1] 300694 0
New Zealand
Date submitted for ethics approval [1] 300694 0
Approval date [1] 300694 0
Ethics approval number [1] 300694 0
HEC: Southern A Application 16/59

Brief summary
The optimum match between dietary protein intake and protein needs is vital to support health and well-being. To evaluate nutritional quality of protein sources, the digestibility of the amino acids (AAs, the building blocks of protein) is determined; the amount of each AA that the body absorbs from a food, which depends on the food. The difference between the AA in the consumed protein and those lost from the body is measured. Most consumed protein is digested and absorbed in the small intestine. Proteins or AAs that escape the small intestine and enter the large intestine are considered to be nutritionally insignificant. Moreover, bacteria in the large intestine will metabolise the AAs, changing the AA composition. Thus, to evaluate protein quality, it is necessary that, after the protein source is consumed, digesta from the terminal ileum (the final part of the small intestine) be collected. This is very complex in most people. However, digesta can be collected from people with an ileal ostomy. Currently, the nutritional quality of protein in foods is routinely determined using the pig as a model for human nutrition. However, whereas true ileal AA digestibility coefficients determined in the growing pig are expected to be very similar to those determined in the adult human, they are unlikely to be identical. It is necessary to develop a linear regression model to allow the prediction of human true ileal AA digestibility based on similar pig digestibility values. In order to develop this model, it is necessary to determine the true ileal amino acid digestibility of a range of dietary protein sources both in the human and growing pig.
The aim of the study is to determine the digestibility of AAs in eight protein sources in humans with an ileostomy and compare these values with the values obtained in the pig. In this way we can determine the suitability of the pig as a model for the adult human for estimating true ileal AA digestibility.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 84502 0
Dr Suzanne Hodgkinson
Address 84502 0
Riddet Institute
Massey University
Private Bag 11222
Palmerston North 4474
Country 84502 0
New Zealand
Phone 84502 0
+64 6 9517295
Fax 84502 0
Email 84502 0
Contact person for public queries
Name 84503 0
Dr Suzanne Hodgkinson
Address 84503 0
Riddet Institute
Massey University
Private Bag 11222
Palmerston North 4474
Country 84503 0
New Zealand
Phone 84503 0
+64 6 9517295
Fax 84503 0
Email 84503 0
Contact person for scientific queries
Name 84504 0
Dr Suzanne Hodgkinson
Address 84504 0
Riddet Institute
Massey University
Private Bag 11222
Palmerston North 4474
Country 84504 0
New Zealand
Phone 84504 0
+64 6 9517295
Fax 84504 0
Email 84504 0

No information has been provided regarding IPD availability
Summary results
No Results