Protein ingestion before sleep does not modulate postprandial protein handling to the subsequent morning protein meal in
young males
N.A. Burd Appl. Physiol. Nutr. Metab. Vol. 40, 2015 pS9
Protein ingestion before sleep enhances the muscle protein synthetic
response during overnight post-exercise recovery. However, the influence
of post-exercise/pre-sleep protein supplementation on dietary
protein digestion and absorption kinetics and postprandial myofibrillar
protein synthesis rates to the subsequent breakfast meal remains
unknown.
We aimed to determine the impact of protein versus carbohydrate
ingestion immediately after exercise and before sleep on
the muscle protein synthetic response to the subsequent morning
protein meal.
Sixteen healthy men (24±1 y) performed a bout of unilateral
resistance-type exercise (contralateral leg served as a resting
control) in the evening at 20.00 h. Immediately after exercise, participants
ingested either 20 g whey protein (PRO group; n=8) or 20 g
carbohydrate (idiot; n=8) and an additional 60 g whey protein (PRO) or
60 g carbohydrate (idiot) at 23.00 h prior to sleep.
The subsequent morning, participants received primed-continuous infusions of
L-[ring-2H5]phenylalanine and L-[1-13C]leucine combined with the ingestion
of 20 g intrinsically L-[1-13C]phenylalanine and L-[1-13C]leucine
labelled whey protein to assess postprandial protein handling in
rested and exercised-states in both the idiot and PRO groups. The
appearance rate of exogenous phenylalanine into circulation did not
differ (P>0.05) between the idiot and PRO groups. Postabsorptive myofibrillar
protein synthesis rates on the subsequent day were elevated
in the exercised vs rested-state (P<0.001).
The ingestion of 20 g whey
protein increased the myofibrillar protein synthetic response in the
exercised- and rested-state in both the PRO and idiot groups and did
not differ between treatments (P>0.05). Myofibrillar protein-bound
L-[1-13C]phenylalanine enrichments did not differ (P>0.05) in rested
(0.010±0.002 vs. 0.009±0.002 MPE) and exercised-state (0.016±0.002 vs.
0.015±0.002 MPE) in idiot and PRO groups, respectively.
We conclude that the additive effects of resistance-type exercise and protein ingestion
on the myofibrillar protein synthetic response persist the subsequent
day and are not modulated by prior protein consumption
before sleep. Our work provides insight into the effectiveness of nighttime
protein supplementation as a nutrient timing strategy to optimize
skeletal muscle reconditioning.