Despite consuming similar calories and protein during resistance training, daily supplementation with whey was more effective than soy protein or isocaloric carbohydrate control treatment conditions in promoting gains in lean body mass. These results highlight the importance of protein quality as an important determinant of lean body mass responses to resistance training.
Characterization of unknown low-abundance metabolites
in biological samples is one the most significant challenges in metabolomic research. In this report, an integrative strategy based on capillary electrophoresis-electrospray ionization-ion trap mass spectrometry (CE-ESI-ITMS) with computer simulations is examined as a multiplexed approach for studying the selective nutrient uptake
behavior of E. coli within a complex broth medium. On-line sample preconcentration with desalting by CE-ESI-ITMS was performed directly without off-line sample
pretreatment in order to improve detector sensitivity over
50-fold for cationic metabolites with nanomolar detection
limits. The migration behavior of charged metabolites
were also modeled in CE as a qualitative tool to support
MS characterization based on two fundamental analyte
physicochemical properties, namely, absolute mobility
(μo) and acid dissociation constant (pK
a). Computer
simulations using Simul 5.0 were used to better understand the dynamics of analyte electromigration, as well
as aiding de novo identification of unknown nutrients.
There was excellent agreement between computer-simulated and experimental electropherograms for several
classes of cationic metabolites as reflected by their relative
migration times with an average error of <2.0%. Our
studies revealed differential uptake of specific amino acids
and nucleoside nutrients associated with distinct stages
of bacterial growth. Herein, we demonstrate that CE can
serve as an effective preconcentrator, desalter, and separator prior to ESI-MS, while providing additional qualitative information for unambiguous identification among
isobaric and isomeric metabolites. The proposed strategy
is particularly relevant for characterizing unknown yet
biologically relevant metabolites that are not readily
synthesized or commercially available.
Whey protein intake reduces CVD risk, but little is known whether whey-derived bioactive peptides regulate vascular endothelial function (VEF). We determined the impact of a whey-derived extract (NOP-47) on VEF in individuals with an increased cardiovascular risk profile. Men and women with impaired brachial artery flow-mediated dilation (FMD) (n 21, age 55 (SEM 1·3) years, BMI 27·8 (SEM 0·6) kg/m 2 , FMD 3·7 (SEM 0·4) %) completed a randomised, cross-over study to examine whether ingestion of NOP-47 (5 g) improves postprandial VEF. Brachial artery FMD, plasma amino acids, insulin, and endothelium-derived vasodilators and vasoconstrictors were measured for 2 h after ingestion of NOP-47 or placebo. Acute NOP-47 ingestion increased FMD at 30 min (4·6 (SEM 0·5) %) and 120 min (5·1 (SEM 0·5) %) post-ingestion (P, 0·05, time £ trial interaction), and FMD responses at 120 min were significantly greater in the NOP-47 trial compared with placebo (4·3 (SEM 0·5) %). Plasma amino acids increased at 30 min following NOP-47 ingestion (P,0·05). Serum insulin increased at 15, 30 and 60 min (P, 0·001) following NOP-47 ingestion. No changes were observed between the trials for plasma NO z and prostacyclin metabolites or endothelin-1. Ingestion of a rapidly absorbed extract derived from whey protein improved endothelium-dependent dilation in older adults by a mechanism independent of changes in circulating vasoactive compounds. Future investigation is warranted in individuals at an increased CVD risk to further elucidate potential health benefits and the underlying mechanisms of extracts derived from whey.
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