Journal Articles
Permanent URI for this collectionhttps://mro.massey.ac.nz/handle/10179/7915
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Item True Ileal Amino Acid Digestibility of Human Foods Classified According to Food Type as Determined in the Growing Pig(Elsevier Inc on behalf of the American Society for Nutrition, 2025-10-18) Hodgkinson SM; Stroebinger N; Stein HH; Fanelli NS; de Vries S; van der Wielen N; Hendriks WH; Moughan PJBackground: A Food and Agriculture Organization Expert Consultation recommended the use of digestible indispensable amino acid score (DIAAS) to evaluate protein quality of foods for humans. Calculation of DIAAS requires true ileal digestibility (TID) of amino acid (AA) values but currently insufficient data are available. Objectives: This study aims to generate in pigs TID of AA for a wide range of foods commonly consumed by humans and determine the range of differences in TID of AA among food types. Methods: A standardized protocol was followed to determine TID of AA in 97 foods across 3 laboratories. Female pigs (25–100 kg during study, n ≥ 6) received foods for 7 d following a Youden Square design with ileal digesta collected via T-cannula on days 6–7. Endogenous AA losses were determined by feeding a protein-free diet. Foods, diets, and digesta were analyzed for nitrogen, AA, reactive lysine, titanium and dry matter. Foods were categorized into food types with the degree of variation within each food type evaluated using descriptive statistics. Results: The TID (mean of AA) ranged from 0.247 (apples) to 0.988 (beef tenderloin). The median TID of AA was high (mean of AA > 0.90) for foods categorized as dairy products, eggs, fish and seafood, isolates and concentrates, meat, nuts, plant-based burgers, soy products and wheat products. Food categories with median TID < 0.80 were baked products, fruit, pulses and seeds, and wheat bran cereal, yeast, and zein. Food categories with low variations between foods were fish and seafood (1% units), dairy products (3% units), and eggs (5% units), whereas categories with the greatest variation were grains (18% units), vegetables (16% units), seeds (14% units), and fruit (12% units). There was considerable variation in TID for individual AA both within and among foods. Conclusions: The database with TID of AA of 97 foods generated by 3 laboratories using a standardized methodology can be utilized for protein quality evaluation.Item Amino acid requirements of the infant: the amino acid composition of human breast milk(Frontiers Media S.A., 2024-09-17) Moughan PJ; Deglaire A; Yan Y; Wescombe P; Lim WXJ; Stroebinger N; Duan S; Szeto IM-Y; Hodgkinson S; Freitas HRThe recommended amino acid requirements of the infant are based on the amino acid composition of mature human breast milk. The amino acid composition of breast milk is usually determined following either acid or alkaline (for tryptophan) hydrolysis. For accuracy, however, the known effect of hydrolysis time on amino acid composition should be accounted for. Also, ideally the amino acid composition of breast milk should be given in units of digested (assumed to be absorbed) amino acids. A review of the literature is presented which gives mean total amino acid concentrations in mature human milk (n = 26 studies), mean hydrolysis correction factors (n = 3 studies) and mean true ileal amino acid digestibility coefficients (n = 3 studies, suckling piglet). There were differences between the estimates of amino acid concentration corrected for hydrolysis time and digestibility, and current FAO (2013) recommendations that were not corrected for these factors. The values based on the published literature up until 2023 (mg/g true protein) corrected for hydrolysis time and digestibility gave higher values (more than 16% higher) for leucine, lysine and threonine, and considerably higher values (greater than 30%) for histidine and tryptophan. Current recommendations may need revision.Item Comparison of True Ileal Amino Acid Digestibility between Adult Humans and Growing Pigs(Oxford University Press on behalf of the American Society for Nutrition, 2022-07) Hodgkinson SM; Stroebinger N; van der Wielen N; Mensink M; Montoya C; Hendriks WH; de Vries S; Stein HH; Moughan PJBACKGROUND: It is not feasible to determine the true ileal amino acid (AA) digestibility of protein sources in humans on a routine basis, and the growing pig has been recommended as an animal model for this purpose but requires further validation. OBJECTIVES: To determine and compare true ileal AA digestibility between adult human ileostomates and growing cannulated pigs for a range of food proteins. METHODS: Seven protein sources (black beans, bread, collagen, pigeon peas, wheat bran, whey protein isolate, and zein) that spanned the range of digestibilities typically seen in foods were evaluated. Six female growing pigs received each of the protein sources, as well as a protein-free diet, and digesta were collected via ileal T-cannula. Adult human ileostomates consumed the same protein sources (5-8 ileostomates, depending on the protein source), as well as a protein-free diet, and digesta were collected. Titanium dioxide and celite were included in the diets as indigestible markers. True ileal AA digestibility coefficients were determined. RESULTS: There was a significant effect of protein source (P ≤ 0.001) for all AAs. The effect of species was not significant (P > 0.05) except for total lysine (but not for available lysine). When analyzed within diets, the statistically significant species effect for true lysine digestibility was found for black beans only. Pig and human digestibility values were generally highly and significantly (P ≤ 0.05) correlated. A linear regression equation derived for true ileal AA digestibility (given as coefficients) determined in the human and pig for the overall mean of all AAs was (y = human, x = pig) y = 1.00x - 0.010, with the slope not statistically significant (P > 0.05) from unity and the intercept not different (P > 0.05) from zero. CONCLUSIONS: True ileal AA digestibility values determined in the growing pig can be directly used for predicting digestibility in adult humans.Item Digestible indispensable amino acid score (DIAAS): 10 years on(Frontiers Media S.A., 2024-07-03) Moughan PJ; Lim WXJ; Berry EThe objective of the review is to revisit the findings of the 2011 Food and Agriculture Organization of the United Nations (FAO) Expert Consultation on Dietary Protein Quality Evaluation in Human Nutrition, and to report on progress on uptake of the findings. It is evident that since 2011 there has been a concerted research effort to enhance an understanding of the protein quality of foods. The validity of the growing pig ileal protein digestibility assay has been confirmed and numerous studies reported using the growing pig as a model to give true ileal amino acid digestibility values for foods as consumed by humans. This has allowed for the determination of digestible indispensable amino acid scores (DIAAS) for a range of foods. A new non-invasive true ileal amino acid digestibility assay in humans which can be applied in different physiological states, called the dual-isotope assay, has been developed and applied to determine the DIAAS values of foods. It is concluded that DIAAS is currently the most accurate score for routinely assessing the protein quality rating of single source proteins. In the future, the accuracy of DIAAS can be enhanced by improved information on: the ideal dietary amino acid balance including the ideal dispensable to indispensable amino acid ratio; dietary indispensable amino acid requirements; effects of processing on ileal amino acid digestibility and lysine bioavailability. There is a need to develop rapid, inexpensive in vitro digestibility assays. Conceptual issues relating DIAAS to food regulatory claims, and to holistic indices of food nutritional and health status are discussed. The first recommendation of the 2011 Consultation regarding treating each indispensable amino acid as an individual nutrient has received little attention. Consideration should be given to providing food label information on the digestible contents of specific indispensable amino acids.