An Evaluation of the Health Efficacy Potential of Combinatorial Proteins in Humans - Digestible Indispensable Amino Acid Score (DIAAS) Effects on Protein Balance and Muscle Protein Synthesis

Expressions of interest for are sought for a fully funded PhD scholarship on effect of combined proteins on protein synthesis, breakdown, and skeletal muscle health.

As a background new proteins have emerged recently from plant, fungal, insect, animal, and microbial sources. These proteins have a lower environmental footprint, which may support the transition to more sustainable food production practices (https://edepot.wur.nl/496402). However, many of these proteins have low indispensable amino acid (IAA) content, relative to more traditional animal source proteins. Combining and blending these proteins, however, has the potential to achieve higher protein-quality scores, complementarity and higher protein efficiency, thereby boosting the potential for human nutrition if the constituent food matrix associates with high true ileal digestibility.

The digestible indispensable amino acid score (DIAAS) has been recommended by the FAO for the evaluation of protein quality in human foods. However, the application of DIAAS to the human health-related phenotype is largely unknown because of lack of data on true ileal amino acid (AA) digestibility of AAs present in foods (PMID: 32710781), and because of limited research correlating DIAAS with health outcomes, such as muscle protein synthesis and insulin sensitivity.

The PhD will involve a reanalysis of an existing dataset comprising the effect of animal (beef, eggs, pork) and plant (tofu, kidney beans, peanut butter, mixed nuts) proteins on whole-body net protein balance to establish the relationship between DIAAS and protein balance and conducting several studies in healthy young and older adults to determine how DIAAS affects anabolic protein metabolism using stable isotope methodology, including creatine labelling and the “virtual muscle biopsy approach”.

Selection Criteria

Essential

Candidates must meet PhD registration requirements and relevant background and interests, which will be a suitable research Masters or Honours 1^st class or equivalent. Professional experience and relevant academic qualifications will be evaluated.

Desirable

Experience in human clinical trials in the nutritional, physiology, or exercise science setting.

Experience with stable isotope methodology or other bench methods of metabolic biochemistry involving mass spectrometry.

Conditions of the application

Both domestic and international applicants are encouraged to apply. International applicants will be required to apply for visa border exemption, with assistance from Massey University.

Capacity to be based at the Auckland Campus.

1. cover letter

2. academic transcripts

3. CV with names and contact details of 2 or 3 referees

PhD scholarship award

The 3 year PhD scholarship award consists of:

·      stipend                                  $30,000 per year

·      student fees                         $8,500 per year

·      project consumables         $10,000 per year

·      publication costs                 $4,500

Please send enquires and applications to Professor David Rowlands:

[Email Address Removed]

0272099383

Please send:

1. cover letter

2. academic record

3. CV

Supervisory Team

Chief Supervisor - David Rowlands

Organisation - School of Sport, Exercise, and Nutrition, Massey University, Auckland

Other supervisors - Carlos Montoya, Elaine Rush, Suzanne Hodgkinson, Rozanne Kruger, John Harrison (Mass Spec), Robert Wolfe (Collaboration), Paul Moughan (Advisory)

AgResearch, Palmerston North AUT, Auckland, Riddet, Massey University

Nutrition and Dietetics, School of Sport, Exercise, and Nutrition, Massey Chemistry, Massey

University of Arkansas for Medical Sciences, Little Rock (USA) and Riddet, Riddet, Massey

Background

New proteins have emerged recently from plant, fungal, insect, animal, and microbial sources. These proteins have a lower environmental footprint, which may support the transition to more sustainable food production practices (https://edepot.wur.nl/496402). However, many of these proteins have low indispensable amino acid (IAA) content, relative to more traditional animal source proteins. Combining and blending these proteins, however, has the potential to achieve higher protein-quality scores, complementarity and higher protein efficiency, thereby boosting the potential for human nutrition if the constituent food matrix associates with high true ileal digestibility.

Overall goal

The project sits within Theme 2 – Sustainable Future Proteins of the Future Foods in Harmony with Nature CoRE programme. The overriding goal is to initiate information gathering on the importance of true protein digestibility (DIAAS) of combinatorial protein matrices to support optimal nutritional functionality for adult human health outcomes, specifically skeletal muscle anabolism relating mass, function, and metabolism. Another overall goal is the expansion and transfer of technology to conduct analysis of stable isotopic amino-acid analysis procedures using mass spectrometry and to build resources to support collaboration and funding from external sources.

Specific Objectives

The specific objectives of the project are to determine the relationship between DIAAS and anabolic potential of novel proteins/combinations in adults and the relationship to skeletal muscle quality in anabolic and insulin resistance. The project will expand the DIAAS dataset towards optimal protein bio-functionality and support database development to predict the behaviour of targeted combinatorial proteins on health outcomes.

Structure

The PhD will comprise several studies (subject to modification according to final objectives):

1. A desktop reanalysis of an existing dataset comprising the effect of animal (beef, eggs, pork) and plant (tofu, kidney beans, peanut butter, mixed nuts) proteins on whole-body net protein balance to establish the relationship between DIAAS and protein balance.

2. In a randomised controlled trial in healthy adults to determine how DIAAS affects anabolic protein metabolism using stable isotope methodology.

3. The trial above is repeated, but in anabolic resistant older-aged men and women.  

4. The efficacy of a metabolically-favourable high vs low DIAAS protein on muscle mass retention using creatine labelling in anabolic and insulin resistant older-aged men and women.