Lysine from Cooked White Rice Consumed by Healthy Young Men Is Highly Metabolically Available When Assessed Using the Indicator Amino Acid Oxidation Technique

Prolla, Ivo Roberto Dorneles; Rafii, Mahroukh; Courtney‐Martin, Glenda; Elango, Rajavel; Silva, Leila P. da; Ball, Ronald O.; Pencharz, Paul B.

doi:10.3945/jn.112.166728

Cited by 27 publications

(17 citation statements)

References 32 publications

(50 reference statements)

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“…An indicator amino acid oxidation method has also been proposed to measure the metabolic availability (including digestion, absorption, and utilization) of specific IAAs. Although noninvasive, since it is a breath test, a disadvantage is that subjects need to be tested repeatedly, and the MA of only one IAA can be studied within an experiment (11, 12, 15).…”

Section: Discussionmentioning

confidence: 99%

“…It has now also been proposed that protein quality should be measured for the content of each IAA, along with the digestibility of each IAA, in relation to the human requirement pattern, in what is now called the digestible indispensable amino acid score (DIAAS) (9, 10). Recently, the metabolic availability (MA) of lysine was measured in humans by a noninvasive, indicator amino acid oxidation technique (11, 12), which had been validated against animal models (13, 14). However, only one amino acid can be assessed for its MA within any experiment (11, 15).…”

Section: Introductionmentioning

confidence: 99%

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Measurement of protein digestibility in humans by a dual-tracer method

Devi

Varkey

Sheshshayee

et al. 2018

The American Journal of Clinical Nutrition

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BackgroundRecent evaluations of the risk of dietary protein deficiency have indicated that protein digestibility may be a key limiting factor in the provision of indispensable amino acids (IAAs), particularly for vulnerable populations living in challenging environments where intestinal dysfunction may exist. Since the digestion of protein occurs only in the small intestine, and the metabolic activity of colonic bacteria confounds measurements at the fecal level, there is a need to develop noninvasive protein digestibility measurements at the ileal level.ObjectiveWe used a dual-tracer method with stable isotopes to characterize the digestibility of uniformly labeled [13C]-spirulina protein as a standard protein, in comparison to a mixture of 2H-labeled crystalline amino acids, and then demonstrated the use of this standard protein to measure the digestibility of selected legumes (chick pea and mung bean) through the use of proteins that were intrinsically labeled with 2H.DesignThe digestibility of uniformly labeled [13C]-spirulina was first measured in 6 healthy volunteers (3 males and 3 females) by feeding it along with a standard mixture of 2H-labeled amino acids, in a dual-tracer, plateau-fed test meal approach. Next, intrinsically labeled legume protein digestibility was studied with a similar dual-tracer approach, with uniformly labeled [13C]-spirulina as the standard, when processed differently before consumption.ResultsThe average digestibility of IAA in spirulina protein was 85.2%. The average IAA digestibility of intrinsically 2H-labeled chick pea and mung bean protein was 56.6% and 57.7%, respectively. Dehulling of mung bean before ingestion increased the average IAA digestibility by 9.9% in comparison to whole mung bean digestibility.ConclusionsAn innovative, minimally invasive “dual-stable-isotope” method was developed to measure protein digestibility, in which the ingestion of an intrinsically 2H-labeled test protein along with a 13C-labeled standard protein of known digestibility allows for an accurate measure of digestion and absorption of the intrinsically labeled protein. This minimally invasive method is critical to redefining protein quality and will aid in revisiting human protein requirements in different settings and in vulnerable populations. This trial was registered at Clinical Trials Registry—India as CTRI/2017/11/010468.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Measurement of protein digestibility in humans by a dual-tracer method

Devi

Varkey

Sheshshayee

et al. 2018

The American Journal of Clinical Nutrition

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“…Recent recommendations have emphasized the importance of dietary protein quality and the need for its assessment by use of the Digestible Indispensable Amino Acid Score, necessitating true ileal digestibility measurements on individual indispensable amino acids (IAAs) with respect to a nutritional reference, such as milk or egg white protein (1). Whereas direct ileal balance measurements have been used to define ileal protein and amino acid digestibility in animals and humans (ileostomates and nasoileal intubation methods), isotopic methods such as the indicator amino acid oxidation method have been used to measure the metabolic availability of specific IAAs, one IAA at a time (2, 3). Recently, a dual isotope method for measuring the human ileal digestibility of different IAAs in intrinsically labeled protein was proposed (4), in which the measurement of absorbed amino acids from a 2 H intrinsically labeled test protein could be compared against that for a 13 C intrinsically labeled standard protein with known digestibility.…”

Section: Introductionmentioning

confidence: 99%

Ileal digestibility of intrinsically labeled hen's egg and meat protein determined with the dual stable isotope tracer method in Indian adults

Kashyap

Shivakumar

Varkey

et al. 2018

The American Journal of Clinical Nutrition

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BackgroundProtein quality assessment through the Digestible Indispensable Amino Acid Score requires accurate measurements of true ileal protein and amino acid digestibility, for which a dual isotope technique was recently developed. However, the ileal digestibility of indispensable amino acids (IAA) in humans from high-quality proteins is not well known.ObjectiveThe aim of this study was to intrinsically label hen's egg and meat protein by the use of uniformly 2H-labeled amino acids, and to measure their true ileal indispensable amino acid (IAA) digestibility via the dual isotope method in humans.Design 2H-labeled lyophilized boiled egg white protein, whole boiled egg, and cooked meat were obtained from layer hens (BV-300) administered a uniformly 2H-labeled amino acid mix orally for 35 d with their daily feed. The ileal IAA digestibility of these proteins was determined with reference to digestibility of previously characterized [U-13C]spirulina in a dual tracer method in healthy Indian subjects whose intestinal health was measured by the plasma kynurenine-to-tryptophan (KT) ratio.ResultsAll subjects had normal KT ratios. The mean ± SD true ileal IAA digestibility of 2H-labeled egg white protein, whole boiled egg, and cooked meat was 86.3% ± 4.6%, 89.4% ± 4.5%, and 92.0% ± 2.8%, respectively. Leucine digestibility correlated with the KT ratio (r = −0.772; P = 0.009).ConclusionsUniformly 2H-labeled hen's egg and meat protein can be used to measure ileal IAA digestibility by the dual isotope tracer approach in humans. The mean IAA digestibility values for these high-quality proteins in the healthy Indians studied were similar to values obtained in earlier human and animal experiments. Leucine digestibility in these meal matrices correlated with the KT ratio, but this aspect needs further evaluation. This trial was registered at the Clinical Trials Registry of India (http://ctri.nic.in) as CTRI/2018/03/012265.

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“…These methods include the non-invasive IAAO technique and the minimally invasive dual stable isotope tracer approach. The IAAO follows the same principle used for IAA requirements but measures the metabolic availability of the limiting AA in the test protein5960. Although non-invasive in nature, IAAO requires repeated experiments in a single individual, and a strict adherence to an adaptation diet that could affect compliance, which limits its use in vulnerable population.…”

Section: Protein Qualitymentioning

confidence: 99%

Protein quality & amino acid requirements in relation to needs in India

Shivakumar¹,

Minocha²,

Kurpad³

2018

Indian J Med Res

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The relevance of protein and its constituent amino acids (AAs) in the structure and function of the human body is well known. Accumulating evidence has conferred specific functional and regulatory roles for individual AAs, adding relevance to their requirements across different age groups. The methods for measuring AA requirements have progressed from the classical nitrogen balance to the current stable isotope-based AA balance methods. Requirements of most of the indispensable AA (IAA) have been estimated in healthy Indian population by the best available balance method and has shown to be higher than earlier 1985 WHO/FAO/UNU (World Health Organization/Food and Agriculture Organization/United Nations University) recommendations. In addition, potential changes in the requirement, through adaptation to chronic undernutrition or to infection, have also been evaluated. In 2007, the WHO/FAO/UNU released a recommendation that increased the daily IAA requirement, based on primary evidence from Indian balance studies. This meant that to ensure that the new IAA requirements were met, individual foods or mixed diets needed to be assessed for their protein quality, or their ability to deliver the required amount of IAA. The recent FAO report on protein quality evaluation recommends the use of a new chemical AA score, the digestible IAA score (DIAAS), to replace the earlier protein digestibility corrected AA score. The DIAAS requires the determination of individual AA digestibility at the ileal level. A minimally invasive dual stable isotope tracer-based approach has been developed in India and has been used to determine digestibility of various foods in Indian adults and children. The increase in IAA requirements and subsequent protein quality requirements have implications for national regulatory frameworks, growth and development, and in turn, for economic and agricultural policy.

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Lysine from Cooked White Rice Consumed by Healthy Young Men Is Highly Metabolically Available When Assessed Using the Indicator Amino Acid Oxidation Technique

Cited by 27 publications

References 32 publications

Measurement of protein digestibility in humans by a dual-tracer method

Measurement of protein digestibility in humans by a dual-tracer method

Ileal digestibility of intrinsically labeled hen's egg and meat protein determined with the dual stable isotope tracer method in Indian adults

Protein quality & amino acid requirements in relation to needs in India

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