Effekt av mjölk på proteinbalans efter träning hos unga

[King Grub]

In adults, adding protein to a post-exercise beverage increases muscle protein turnover and replenishes amino acid stores. Recent focus has shifted towards the use of bovine-based milk and milk products as potential post-exercise beverages; however, little is known about how this research translates to the pediatric population. Twenty-eight (15 females) pre- to early-pubertal (PEP, 7-11yrs) and mid- to late-pubertal (MLP, 14-17yrs) children consumed an oral dose of [15N]glycine prior to performing 2 × 20-min cycling bouts at 60% VO2peak in a warm environment (34.5°C, 47.3% relative humidity). Following exercise, participants consumed either water (W), a carbohydrate-electrolyte solution (CES), or skim milk (SM) in randomized, cross-over fashion in a volume equal to 100% of their body mass loss during exercise. Whole body nitrogen turnover (Q), protein synthesis (S), protein breakdown (B), and whole body protein balance (WBPB) were measured over 16h. Protein intake from SM was 0.40 ± 0.10 g/kg. Over 16h, Q and S were significantly greater (p < 0.01) with SM than W and CES. B demonstrated a trend for a main effect for beverage (p = 0.063). WBPB was more negative (p<0.01) with W and CES than with SM. In the SM trial, WBPB was positive in PEP while it remained negative in MLP. Boys exhibited significantly more negative WBPB than girls (p<0.05). Post-exercise milk consumption enhances WBPB compared to W and CES; however, additional protein intake may be required to sustain a net anabolic environment over 16h.

Effects of post-exercise milk consumption on whole body protein balance in youth. Journal of Applied Physiology 25 September 2014 Vol. no. , DOI: 10.1152/japplphysiol.01227.2013.

http://jap.physiology.org/content/early/2014/09/23/japplphysiol.01227.2013.full-text.pdf%2Bhtml