Whey Protein Supplementation Does Not Alter Plasma Branched-Chained @entity535 Profiles but Results in Unique Metabolomics Patterns in Obese XXXX Enrolled in an 8-Week Weight Loss Trial.

@entity1 @entity28 @entity535 @entity209 @entity2569 @entity2596
BACKGROUND: It has been suggested that perturbations in branched-chain @entity535 (BCAA) catabolism are associated with insulin resistance and contribute to elevated systemic BCAAs. Evidence in rodents suggests dietary protein rich in BCAAs can increase BCAA catabolism, but there is limited evidence in @entity1 . OBJECTIVE: We hypothesize that a diet rich in BCAAs will increase BCAA catabolism, which will manifest in a reduction of fasting plasma BCAA concentrations. METHODS: The metabolome of 27 @entity28 @entity1 with @entity209 before and after weight loss was investigated to identify changes in BCAA metabolism using GC-time-of-flight mass spectrometry. Subjects were enrolled in an 8-wk weight-loss study including either a 20-g/d whey (whey group, n = 16) or gelatin (gelatin group, n = 11) protein supplement. When matched for total protein by weight, whey protein has 3 times the amount of BCAAs compared with gelatin protein. RESULTS: Postintervention plasma abundances of Ile (gelatin group: 637    18, quantifier ion peak height    100; whey group: 744    65), Leu (gelatin group: 1210    33; whey group: 1380    79), and @entity2596 (gelatin group: 2080    59; whey group: 2510    230) did not differ between treatment groups. BCAAs were significantly correlated with homeostasis model assessment of insulin resistance at baseline (r = 0.52, 0.43, and 0.49 for Leu, Ile, and @entity2596 , respectively; all, P < 0.05), but correlations were no longer significant at postintervention. Pro- and @entity2569 -related pathways were found discriminant of whey protein vs. gelatin protein supplementation in multivariate statistical analyses. CONCLUSIONS: These findings suggest that BCAA metabolism is, at best, only modestly affected at a whey protein supplementation dose of 20 g/d. Furthermore, the loss of an association between postintervention BCAA and homeostasis model assessment suggests that factors associated with calorie restriction or protein intake affect how plasma BCAAs relate to insulin sensitivity. This trial was registered at clinicaltrials.gov as NCT00739479.
