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Whey protein supplementation does not alter plasma branched-chained amino acid profiles but results in unique metabolomics patterns in obese women enrolled in an 8-week weight loss trial.
Piccolo, BD, Comerford, KB, Karakas, SE, Knotts, TA, Fiehn, O, Adams, SH
The Journal of nutrition. 2015;(4):691-700
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Abstract
BACKGROUND It has been suggested that perturbations in branched-chain amino acid (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 humans. 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 obese women with metabolic syndrome 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 Val (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 Val, respectively; all, P < 0.05), but correlations were no longer significant at postintervention. Pro- and Cys-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.
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Whey protein supplementation does not affect exercise training-induced changes in body composition and indices of metabolic syndrome in middle-aged overweight and obese adults.
Weinheimer, EM, Conley, TB, Kobza, VM, Sands, LP, Lim, E, Janle, EM, Campbell, WW
The Journal of nutrition. 2012;(8):1532-9
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Abstract
Little is known about the effects of different quantities of whey protein on exercise training-induced changes in body composition and indices of metabolic syndrome in middle-aged overweight and obese adults. Therefore, we examined the effects of consuming 0.8-MJ supplements with 0 (n = 126), 10 (n = 112), 20 (n = 44), or 30 (n = 45) g whey protein twice daily in conjunction with resistance (2 d/wk) and aerobic (1 d/wk) exercise training in a double-blind, randomized, placebo-controlled, community-based 9-mo study in men (n = 117) and women (n = 210); (age: 48 ± 7.9 y; BMI: 30.0 ± 2.8 kg/m(2)). Whey protein supplementation did not influence any of the following outcomes, some of which were affected by training. Among all participants, strength increased by 15 ± 12% (P < 0.001) and maximal oxygen uptake capacity (VO(2)max) increased by 9 ± 15% (P < 0.001). Body weight was unchanged (0.1 ± 3.7 kg, P = 0.80), lean body mass increased by 1.9 ± 2.8% (0.95 ± 1.3 kg, P < 0.001), and fat mass decreased by 2.6 ± 9.4% (-0.86 ± 3.1 kg, P = 0.001). Oral-glucose-tolerance testing showed that plasma glucose AUC was unchanged (-18.0 ± 170 mmol/L· 3 h, P = 0.16), insulin AUC decreased by 2.6 ± 32% (-7.5 ± 29 nmol/L· 3 h, P = 0.01), and HOMA-IR (0.2 ± 2.0, P = 0.81) and the insulin sensitivity index (0.3 ± 3.0, P = 0.63) were unchanged. Plasma concentrations of TG; total, LDL, and HDL cholesterol; C-reactive protein; plasminogen activator inhibitor-1; blood pressure; and waist circumference were unchanged. Whey protein supplementation did not affect exercise training-induced responses in body composition and indices of metabolic syndrome in middle-aged overweight and obese adults who maintained body weight.