title: Postexercise protein ingestion increases whole body net protein balance in healthy children.
abstract: Postexercise protein ingestion increases whole body and muscle protein anabolism in adults. No study has specifically investigated the combined effects of exercise and protein ingestion on protein metabolism in healthy, physically active children. Under 24-h dietary control, 13 (seven males, six females) active children (∼ 11 yr old; 39.3 ± 5.9 kg) consumed an oral dose of [(15)N]glycine prior to performing a bout of exercise. Immediately after exercise, participants consumed isoenergetic mixed macronutrient beverages containing a variable amount of protein [0, 0.75, and 1.5 g/100 ml for control (CON), low protein (LP), and high protein (HP), respectively] according to fluid losses. Whole body nitrogen turnover (Q), protein synthesis (S), protein breakdown (B), and protein balance (WBPB) were measured throughout exercise and the early acute recovery period (9 h combined) as well as over 24 h. Postexercise protein intake from the beverage was ∼ 0.18 and ∼ 0.32 g/kg body mass for LP and HP, respectively. Q, S, and B were significantly greater (main effect time, all P < 0.001) over 9 h compared with 24 h with no differences between conditions. WBPB was also greater over 9 h compared with 24 h in all conditions (main effect time, P < 0.001). Over 9 h, WBPB was greater in HP (P < 0.05) than LP and CON with a trend (P = 0.075) toward LP being greater than CON. WBPB was positive over 9 h for all conditions but only over 24 h for HP. Postexercise protein ingestion acutely increases net protein balance in healthy children early in recovery in a dose-dependent manner with larger protein intakes (∼ 0.32 g/kg) required to sustain a net anabolic environment over an entire 24 h period.
authors.affiliation: Physical Performance and Mobility Group, Nestle Research Centre, Lausanne, Switzerland; Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Canada; and dr.moore@utoronto.ca.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Moore
authors.affiliation: Child Health and Exercise Medicine Program, Department of Pediatrics, McMaster University, Hamilton, Canada.
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Volterman
authors.affiliation: Child Health and Exercise Medicine Program, Department of Pediatrics, McMaster University, Hamilton, Canada.
authors.forename: Joyce
authors.initials: J
authors.lastname: Obeid
authors.affiliation: Physical Performance and Mobility Group, Nestle Research Centre, Lausanne, Switzerland;
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Offord
authors.affiliation: Child Health and Exercise Medicine Program, Department of Pediatrics, McMaster University, Hamilton, Canada.
authors.forename: Brian W
authors.initials: BW
authors.lastname: Timmons
mesh_terms: D000284:Administration, Oral; D000367:Age Factors; D001628:Beverages; D002648:Child; D002664:Child Nutritional Physiological Phenomena; D018592:Cross-Over Studies; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000378:metabolism*; D015596:Nutrition Assessment; D009752:Nutritional Status; D009864:Ontario; D020127:Recovery of Function; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D004044:Dietary Proteins
keywords: lean body mass; physical activity; protein requirements; protein synthesis; youth