Quantifying the contribution of dietary protein to whole body protein kinetics: examination of the intrinsically-labeled proteins method.

08:00 EDT 2nd April 2019 | BioPortfolio

Summary of "Quantifying the contribution of dietary protein to whole body protein kinetics: examination of the intrinsically-labeled proteins method."

Intrinsically-labeled dietary proteins have been used to trace various aspects of digestion and absorption, including quantifying the contribution of dietary protein to observed post-prandial amino acid and protein kinetics in human subjects. Quantification of the rate of appearance in peripheral blood of an unlabeled (tracee) amino acid originating from an intrinsically-labeled protein (exogenous Ra) requires the assumption that there is no dilution of the isotope enrichment of the protein-bound amino acid in the gastrointestinal tract (GIT) or across the splanchnic bed. It must also be assumed that the effective volume of distribution (pV) into which the tracer and tracee appear can be reasonably estimated by a single value, and that any recycling of the tracer is minimal and thus does not affect calculated rates. We have assessed these assumptions quantitatively using values from published studies. We conclude that the use of intrinsically-labeled proteins as currently described to quantify exogenous Ra systematically underestimates the true value. When used with the tracer-determined rates of amino acid kinetics, underestimation of exogenous Ra from the intrinsically-labeled protein method likely translates to incorrect conclusions regarding protein breakdown, including the effect of a protein meal, and the anabolic impact of the speed of digestion and absorption of amino acids. Estimation of exogenous Ra from the bioavailability of ingested protein has some advantages as compared with the intrinsically-labeled protein method. We therefore conclude that the bioavailability method for estimating exogenous Ra is preferable to the intrinsically-labeled protein method.


Journal Details

This article was published in the following journal.

Name: American journal of physiology. Endocrinology and metabolism
ISSN: 1522-1555


DeepDyve research library

PubMed Articles [26139 Associated PubMed Articles listed on BioPortfolio]

Body Protein Reserves Sustain Maternal Performance in Early Lactation but Dietary Protein Is Necessary to Maintain Performance and Immune Responses to Nippostrongylus brasiliensis in Lactating Rats.

It has been shown that dietary protein supplementation during lactation boosts immunity in Nippostrongylus brasiliensis-infected periparturient rats. It is not known whether body protein reserves accu...

The Importance of Dietary Protein at Breakfast in Childhood.

In order for the body to maintain a healthy and normal steady state of lean body mass, body proteins constantly undergo breakdown and synthesis. The rate at which lean tissue is synthetized must equal...

The Effect of Dietary Protein on Protein Metabolism and Performance in Endurance-trained Males.

Recommendations for dietary protein are based primarily intakes that maintain nitrogen (i.e. protein) balance rather than optimize metabolism and/or performance.

Dietary fructooligosaccharide can mitigate the negative effects of immunity on Chinese mitten crab fed a high level of plant protein diet.

An 8-week feeding trial was carried out under controlled condition to evaluate the effect of dietary fructooligosaccharide (FOS) on growth performance, whole body composition, antioxidant status and i...

Toxicokinetics and Biliary Excretion of N-Nitrosodiethylamine in Rat Supplemented with Low and High Dietary Proteins.

Although biliary excretion is one of the biological elimination processes for foreign compounds, intake of high-protein diets was hypothesized to enhance their detoxification rates. Hence, this study ...

Clinical Trials [8595 Associated Clinical Trials listed on BioPortfolio]

Role of Dietary Protein Intake in Elderly Adults

The investigators examined the effects of dietary protein intake in a mixed meal at two levels of protein amount on whole body protein metabolisms in older adults.

Real-time Amino Acid Profiling

This study was designed to obtain information about the effect of new combinations of dairy proteins, in small servings with high protein concentrations, on postprandial amino acid kinetic...

Effect of Dietary Protein Intake Distribution on Protein Metabolism and Skeletal Muscle

The investigators determined effects of 8-week dietary protein intake in mixed meals with uneven or even consumption pattern on the metabolic outcomes of whole-body net protein synthesis a...

Influence of Protein Hydrolysis on Dietary Protein Digestibility and Metabolism in Healthy Subjects

Hydrolysis of dietary protein may impact their gastrointestinal kinetics and further metabolism. The primary goal of this work was to measure the metabolic fate of intact or hydrolyzed pro...

Dietary Protein Requirement of Elderly Men and Women

The purpose of this study was to assess the effect of age on the estimated average requirement and adequate allowance for dietary protein.

Medical and Biotech [MESH] Definitions

The lack of sufficient energy or protein to meet the body's metabolic demands, as a result of either an inadequate dietary intake of protein, intake of poor quality dietary protein, increased demands due to disease, or increased nutrient losses.

A layer of protein coating adsorbed by NANOPARTICLES upon entry into PLASMA or other protein-containing biological fluids, which affects how nanoparticles are internalized by cells and cleared from the body.

A pro-apoptotic protein and member of the Bcl-2 protein family that is regulated by PHOSPHORYLATION. Unphosphorylated Bad protein inhibits the activity of BCL-XL PROTEIN.

A multi-domain mitochondrial membrane protein and member of the bcl-2 Protein family. Bak protein interacts with TUMOR SUPPRESSOR PROTEIN P53 and promotes APOPTOSIS.

A member of the Bcl-2 protein family and homologous partner of C-BCL-2 PROTO-ONCOGENE PROTEIN. It regulates the release of CYTOCHROME C and APOPTOSIS INDUCING FACTOR from the MITOCHONDRIA. Several isoforms of BCL2-associated X protein occur due to ALTERNATIVE SPLICING of the mRNA for this protein.

Quick Search


DeepDyve research library

Relevant Topic

Within medicine, nutrition (the study of food and the effect of its components on the body) has many different roles. Appropriate nutrition can help prevent certain diseases, or treat others. In critically ill patients, artificial feeding by tubes need t...

Searches Linking to this Article