Whole-body protein kinetic models to quantify the anabolic response to dietary protein consumption
Summary: Determination of whole body rates of protein synthesis, breakdown and net balance in human subjects still has an important role in nutrition research. Quantifying the anabolic response to dietary protein intake is a particularly important application. There are different models with which t...
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doaj-95f03b53e16041ab80b53e8f3d0690f02021-04-26T05:58:38ZengElsevierClinical Nutrition Open Science2667-26852021-04-01367890Whole-body protein kinetic models to quantify the anabolic response to dietary protein consumptionRobert R. Wolfe0Il-Young Kim1David D. Church2Paul J. Moughan3Sanghee Park4Arny A. Ferrando5University of Arkansas for Medical Sciences, 4301 West Markham Street, Slot 806, Little Rock, AR, 72205-7199, USA; Corresponding author.Department of Molecular Medicine, College of Medicine, Gachon University, South Korea; Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, 155 Gaetbeol-ro, Yeonsu-gu, Incheon, 21999, South KoreaUniversity of Arkansas for Medical Sciences, 4301 West Markham Street, Slot 806, Little Rock, AR, 72205-7199, USARiddet Institute, Massey University, Palmerston North, New ZealandDepartment of Molecular Medicine, College of Medicine, Gachon University, South Korea; Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, 155 Gaetbeol-ro, Yeonsu-gu, Incheon, 21999, South KoreaUniversity of Arkansas for Medical Sciences, 4301 West Markham Street, Slot 806, Little Rock, AR, 72205-7199, USASummary: Determination of whole body rates of protein synthesis, breakdown and net balance in human subjects still has an important role in nutrition research. Quantifying the anabolic response to dietary protein intake is a particularly important application. There are different models with which to accomplish this goal, each with advantages and limitations.The nitrogen (N)-flux method in which tracer is given orally has distinct advantages in terms of lack of invasiveness. In addition, the calculated results include all aspects of whole-body protein synthesis and breakdown. However, the prolonged timeframe of the method eliminates the possibility of the “pre-post” experimental design whereby each subject serves as their own control in the evaluation of the response to a meal.Models based on the primed-constant infusion of an essential amino acid (EAA) tracer enable the determination of baseline whole-body protein kinetics within 2 h, and can quantify a dynamic change from the basal state. The greatest challenge when using an EAA model is distinguishing exogenous and endogenous sources of the tracee in the blood. One approach is to use an intrinsically-labeled protein. This method has the advantage that the exogenous tracee is clearly distinguished from endogenous tracee. On the other hand, the intrinsically-labeled protein method suffers from unmeasured dilution that is likely to cause the systematic underestimation of the rate of appearance of exogenous tracee and thus overestimate the rate of whole-body protein breakdown. Alternatively, the “bioavailability” approach estimates the contribution of exogenous tracee to the peripheral circulation from the amount of tracee ingested, the true ileal digestibility of the tracee, and the irreversible loss of tracee prior to entry into the peripheral circulation. Errors in assumed values with the bioavailability method can potentially be significant, but are not likely to result in the systematic over- or under-estimations of rates of whole-body protein synthesis and breakdown.The optimal method depends on the degree of uncertainty regarding required assumptions in a particular circumstance. With all methods, it is advisable to calculate upper and lower bounds of whole body protein kinetics, in accord with reasonable maximal and minimal assumed values. Simultaneous use of two methods requiring different assumptions can also serve to confirm the validity of single approach.http://www.sciencedirect.com/science/article/pii/S2667268521000115Stable isotope tracersIntrinsically-labeled proteinsBioavailabilityNitrogen flux |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Robert R. Wolfe Il-Young Kim David D. Church Paul J. Moughan Sanghee Park Arny A. Ferrando |
spellingShingle |
Robert R. Wolfe Il-Young Kim David D. Church Paul J. Moughan Sanghee Park Arny A. Ferrando Whole-body protein kinetic models to quantify the anabolic response to dietary protein consumption Clinical Nutrition Open Science Stable isotope tracers Intrinsically-labeled proteins Bioavailability Nitrogen flux |
author_facet |
Robert R. Wolfe Il-Young Kim David D. Church Paul J. Moughan Sanghee Park Arny A. Ferrando |
author_sort |
Robert R. Wolfe |
title |
Whole-body protein kinetic models to quantify the anabolic response to dietary protein consumption |
title_short |
Whole-body protein kinetic models to quantify the anabolic response to dietary protein consumption |
title_full |
Whole-body protein kinetic models to quantify the anabolic response to dietary protein consumption |
title_fullStr |
Whole-body protein kinetic models to quantify the anabolic response to dietary protein consumption |
title_full_unstemmed |
Whole-body protein kinetic models to quantify the anabolic response to dietary protein consumption |
title_sort |
whole-body protein kinetic models to quantify the anabolic response to dietary protein consumption |
publisher |
Elsevier |
series |
Clinical Nutrition Open Science |
issn |
2667-2685 |
publishDate |
2021-04-01 |
description |
Summary: Determination of whole body rates of protein synthesis, breakdown and net balance in human subjects still has an important role in nutrition research. Quantifying the anabolic response to dietary protein intake is a particularly important application. There are different models with which to accomplish this goal, each with advantages and limitations.The nitrogen (N)-flux method in which tracer is given orally has distinct advantages in terms of lack of invasiveness. In addition, the calculated results include all aspects of whole-body protein synthesis and breakdown. However, the prolonged timeframe of the method eliminates the possibility of the “pre-post” experimental design whereby each subject serves as their own control in the evaluation of the response to a meal.Models based on the primed-constant infusion of an essential amino acid (EAA) tracer enable the determination of baseline whole-body protein kinetics within 2 h, and can quantify a dynamic change from the basal state. The greatest challenge when using an EAA model is distinguishing exogenous and endogenous sources of the tracee in the blood. One approach is to use an intrinsically-labeled protein. This method has the advantage that the exogenous tracee is clearly distinguished from endogenous tracee. On the other hand, the intrinsically-labeled protein method suffers from unmeasured dilution that is likely to cause the systematic underestimation of the rate of appearance of exogenous tracee and thus overestimate the rate of whole-body protein breakdown. Alternatively, the “bioavailability” approach estimates the contribution of exogenous tracee to the peripheral circulation from the amount of tracee ingested, the true ileal digestibility of the tracee, and the irreversible loss of tracee prior to entry into the peripheral circulation. Errors in assumed values with the bioavailability method can potentially be significant, but are not likely to result in the systematic over- or under-estimations of rates of whole-body protein synthesis and breakdown.The optimal method depends on the degree of uncertainty regarding required assumptions in a particular circumstance. With all methods, it is advisable to calculate upper and lower bounds of whole body protein kinetics, in accord with reasonable maximal and minimal assumed values. Simultaneous use of two methods requiring different assumptions can also serve to confirm the validity of single approach. |
topic |
Stable isotope tracers Intrinsically-labeled proteins Bioavailability Nitrogen flux |
url |
http://www.sciencedirect.com/science/article/pii/S2667268521000115 |
work_keys_str_mv |
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