None listed
Conditions
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.
Interventions
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 partic
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.
Sponsors
Riddet Institute, Massey University
Study design
Allocation
Randomised controlled trial
Intervention model
Other
Primary purpose
Prevention
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to 70 Years
Healthy volunteers
No
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.
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
Outcome results
None listed