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Similar 24h anabolic response to intact and hydrolysed whey protein ingested postexercise in elderly subjects
Author(s) -
Esmarck Birgitte,
Diederichsen Louise,
Hall Gerrit,
Babraj John,
Smith Kenneth,
Rennie Michael J,
Kjaer Michael
Publication year - 2006
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.20.5.a1469-c
Subject(s) - anabolism , hydrolysate , ingestion , leucine , protein catabolism , chemistry , medicine , endocrinology , hydrolysis , whey protein , carbohydrate , food science , amino acid , biochemistry
Since peptides are absorbed faster than intact proteins it was hypothesized that ingestion of protein hydrolysate after resistance exercise would cause a greater anabolic response than intact protein as timing is of significance in elderly. Muscle protein turnover was measured during a 27 h infusion of L‐[1‐ 13 C]‐leucine in 7 healthy (5M and 2F) aged 71(4) yr (mean(SEM)) who received on separate days carbohydrate with intact, IP or hydrolyzed whey protein, HP (0.25g/kg ~ 18g) over a 2h period after resistance exercise. Arteriovenous samples and muscle biopsies were obtained. Evaluated 1–1.5 h postexercise net balance of leucine was positive, although highest (p<0.05) in IP (0.38 ± 0.07 v 0.09 ± 0.08 mg*h −1 *leg −1 ). Accordingly, was AUC of art‐[leucine] higher in IP than HP (6.2 ± 0.5 v 5.4 ± 0.4 mmol/L). Subsequently, no difference was observed. Further, no differences were observed at any time point between IP and HP for protein synthesis, breakdown or oxidation. Muscle fractional synthetic rate was not different between IP an HP over 4 (0.07 ± 0.01 v 0.09 ± 0.01 %/h) or 24 hours post‐exercise (0.08 ± 0.01 v 0.09 ± 0.01 %/h). These results suggest that protein ingested after resistance exercise in elderly results in a transient positive net protein synthesis, with no overall difference in the anabolic response between intact and hydrolysed whey.