Ferrando A.A.,Donald W Reynolds Institute On Aging
Journal of Nutrition | Year: 2013
Special operations are so designated for the specialized military missions they address. As a result, special operations present some unique metabolic challenges. In particular, soldiers often operate in a negative energy balance in stressful and demanding conditions with little opportunity for rest or recovery. In this framework, findings inferred from the performance literature suggest that increased protein intake may be beneficial. In particular, increased protein intake during negative caloric balance maintains lean body mass and blood glucose production. The addition of protein to mixed macronutrient supplements is beneficial for muscle endurance and power endpoints, and the use of amino acids improves gross and fine motor skills. Increasing protein intake during periods of intense training and/or metabolic demand improves subsequent performance, improves muscular recovery, and reduces symptoms of psychological stress. Consumption of protein before sleep confers the anabolic responses required for the maintenance of lean mass and muscle recovery. A maximal response in muscle protein synthesis is achieved with the consumption of 20-25 g of protein alone. However, higher protein intakes in the context ofmixed-nutrient ingestion also confer anabolic benefits by reducing protein breakdown. Restricted rations issued to special operators provide less than the RDA for protein (;0.6 g/kg), and these soldiers often rely on commercial products to augment their rations. The provision of reasonable alternatives and/or certification of approved supplements by the U.S. Department of Defense would be prudent. © 2013 American Society for Nutrition.
Kim I.-Y.,Donald W Reynolds Institute On Aging |
Schutzler S.,Donald W Reynolds Institute On Aging |
Schrader A.,University of Arkansas for Medical Sciences |
Spencer H.,University of Arkansas for Medical Sciences |
And 4 more authors.
American Journal of Physiology - Endocrinology and Metabolism | Year: 2015
To examine whole body protein turnover and muscle protein fractional synthesis rate (MPS) following ingestions of protein in mixed meals at two doses of protein and two intake patterns, 20 healthy older adult subjects (52–75 yr) participated in one of four groups in a randomized clinical trial: a level of protein intake of 0.8 g (1RDA) or 1.5 g·kg-1·day-1 (∼2RDA) with uneven (U: 15/20/65%) or even distribution (E: 33/33/33%) patterns of intake for breakfast, lunch, and dinner over the day (1RDA-U, 1RDA-E, 2RDA-U, or 2RDA-E). Subjects were studied with primed continuous infusions of L-[2H5]phenylalanine and L-[2H2]tyrosine on day 4 following 3 days of diet habituation. Whole body protein kinetics [protein synthesis (PS), breakdown, and net balance (NB)] were expressed as changes from the fasted to the fed states. Positive NB was achieved at both protein levels, but NB was greater in 2RDA vs. 1RDA (94.8 ± 6.0 vs. 58.9 ± 4.9 g protein/750 min; P = 0.0001), without effects of distribution on NB. The greater NB was due to the higher PS with 2RDA vs. 1RDA (15.4 ± 4.8 vs. ±18.0 ± 8.4 g protein/750 min; P ± 0.0018). Consistent with PS, MPS was greater with 2RDA vs. 1RDA, regardless of distribution patterns. In conclusion, whole body net protein balance was greater with protein intake above recommended dietary allowance (0.8 g protein·kg-1·day-1) in the context of mixed meals, without demonstrated effects of protein intake pattern, primarily through higher rates of protein synthesis at whole body and muscle levels. © 2015 the American Physiological Society.