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Acute Effect of Whey Protein Microgels on Whole Body Protein Turnover in Overweight Adults
Author(s) -
Godin JeanPhilippe,
Kassis Amira
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.742.12
Subject(s) - whey protein , postprandial , chemistry , leucine , casein , protein turnover , digestion (alchemy) , crossover study , amino acid , protein metabolism , protein catabolism , medicine , complete protein , overweight , endocrinology , food science , biochemistry , protein biosynthesis , obesity , placebo , insulin , chromatography , alternative medicine , pathology
Differences in protein digestion and absorption are hypothesized to translate into differences in whole body protein synthesis. Whey protein is qualified as a “fast protein” in relation to its speed of digestion and ensuing aminoacidemia in comparison to casein, the “slow protein”. WP has previously been reported to incur a higher muscle protein synthesis as compared to casein; however results are inconsistent at the whole body level. Whey protein microgels (WPM) are aggregates of whey protein allowing the inclusion of high concentrations of whey protein in liquid matrices. Given that WPM have been shown to result in a delayed appearance of amino acids in the plasma as compared to native WP, we investigated the acute effect of WPM on whole body protein turnover using stable isotope methodology, as compared to micellar casein (MC) in a crossover trial on 7 overweight subjects consuming 4 different isocaloric meals: 1) carbohydrate control 2) 30g of WPM, 3) 50g of WPM (WPM50) and 4) 50g of MC (MC50). WPM50 resulted in higher (p<0.0001) plasma levels of leucine, branched chain, and total amino acids as compared to MC50. We observed no significant difference in non‐oxidative leucine disposal whereas protein oxidation was significantly different (p<0.05) between groups, 170.3 ± 5.4, and 334.9 ± 39 for MC50 and WPM50, respectively. Postprandial Leu balance was similar for WPM50 and MC50. We conclude that at a dose of 50g, the effect of WPM on whole body protein synthesis is not significantly different from that of MC, whereas the resulting Leu protein oxidation and plasma amino acids are higher. The lack of effect could be partly explained by the high dose of protein administered potentially reaching a plateau in whole body protein synthesis, as was previously shown on skeletal muscle.