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Evidenced based practice guidelines for nutrition support recommend implementation of early enteral nutrition (EEN) in certain patient populations, including trauma and critical illness. Early enteral nutrition has been associated with immune benefits, improved healing, reduced length of stay, and a trend towards a reduction in mortality. Rapid evacuation of combat casualties across the continuum of care presents challenges to implementing EEN during wartime operations. This is the first study to examine enteral feeding practices for combat casualties during Operation Iraqi Freedom. The study method was a prospective records review of all U.S. military combat casualties evacuated from a Combat Support Hospital (CSH) in Iraq, from 1 November to 31 December 2006. The results of this study suggest that casualties who meet the criteria for EEN are not receiving it at the CSH in theater. Further research is needed to explore the impact of delayed enteral nutrition in the combat casualty.

Purpose: This study examined how a high-protein diet affected nitrogen balance and protein turnover during an exercise-induced energy deficit. Methods: Twenty-two men completed a 4-d (D1-4) baseline period (BL) of an energy balance diet while maintaining usual physical activity level, followed by 7 d (D5-11) of 1000 kcal[middle dot]d-1 increased energy expenditure via exercise (50-65% V[spacing dot above]O2peak). One group consumed 0.9 g of protein per kilogram per day and maintained energy balance throughout the 11-d intervention (BAL, N = 8). The other two groups consumed their BL energy intake throughout the 11 days, resulting in a 7-d, 1000-kcal[middle dot]d-1 energy deficit. These groups consumed either 0.9 g of protein per kilogram per day (DEF, N = 7) or 1.8 g of protein per kilogram per day (DEF-HP, N = 7). Mean nitrogen balance (NB), calculated per kilogram of fat-free mass (FFM), was determined for BL, days 5-8 (EX1), and days 9-11 (EX2). Whole-body protein turnover was derived from phenylalanine and tyrosine kinetics assessed while fasting at rest on days 4, 7, and 12, using a priming dose of L-[ring-15N]tyrosine and a 4-h, primed, continuous infusion of L-[15N]phenylalanine and L-[ring-2H4]tyrosine. Results: DEF experienced a decrease in NB from BL to EX 1 that was maintained in EX 2. No changes in NB occurred for BAL or DEF-HP over time. No within- or between-group differences were found over time for Phe flux (Qp), conversion rate of Phe to Tyr (Qpt), or the derived protein synthesis value (Sp). Conclusion: Increased dietary protein maintained NB during exercise-induced energy deficit, but this did not impact resting whole-body protein turnover

The purpose of this study was to determine the impact of dietary factors and exercise-associated factors on the response of IGF-I and its binding proteins (IGFBPs) during a period of increased physical activity. Twenty-nine men completed a 4-day ( days 1–4) baseline period of a controlled energy balanced diet while maintaining their normal physical activity level followed by 7 days ( days 5–11) of a 1,000 kcal/day increase in physical activity above their normal activity levels. Two subject groups, one sedentary (Sed, mean V̇o2peak: 39 ml·kg−1·min−1, n = 7) and one fit (FIT1, mean V̇o2peak: 56 ml·kg−1·min−1, n = 8) increased energy intake to maintain energy balance throughout the 7-day intervention. In two other fit subject groups (FIT2, n = 7 and FIT3, n = 7), energy intake remained at baseline resulting in a 1,000 kcal/day exercise-induced energy deficit. Of these, FIT2 received an adequate protein diet (0.9 g/kg), and FIT3 received a high-protein diet (1.8 g/kg). For all four groups, IGF-I, IGFBP-3, and the acid labile subunit (ALS) were significantly decreased by day 11 (27 ± 4%, 10 ± 2%, and 19 ± 4%, respectively) and IGFBP-2 significantly increased by 49 ± 21% following day 3. IGFBP-1 significantly increased only in the two negative energy balance groups, FIT2 (38 ± 6%) and FIT3 (46 ± 8%). Differences in initial fitness level and dietary protein intake did not alter the IGF-I system response to an acute increase in physical activity. Decreases in IGF-I were observed during a moderate increase in physical activity despite maintaining energy balance, suggesting that currently unexplained exercise-associated mechanisms, such as increased energy flux, regulate IGF-I independent of energy deficit.

HAGOBIAN, T. A., K. A. JACOBS, A. W. SUBUDHI, J. A. FATTOR, P. B. ROCK, S. R. MUZA, C. S. FULCO, B. BRAUN, A. GREDIAGIN, R. S. MAZZEO, A. CYMERMAN, and A. L. FRIEDLANDER. Cytokine Responses at High Altitude: Effects of Exercise and Antioxidants at 4300 m. Med. Sci. Sports Exerc., Vol. 38, No. 2, pp. 276–285, 2006. Purpose: This study tested the hypothesis that antioxidant supplementation would attenuate plasma cytokine (IL-6, tumor necrosis factor (TNF)-!), and Creactive protein (CRP) concentrations at rest and in response to exercise at 4300-m elevation. Methods: A total of 17 recreationally trained men were matched and assigned to an antioxidant (N = 9) or placebo (N = 8) group in a double-blinded fashion. At sea level (SL), energy expenditure was controlled and subjects were weight stable. Then, 3 wk before and throughout high altitude (HA), an antioxidant supplement (10,000 IU "-carotene, 200 IU !-tocopherol acetate, 250 mg ascorbic acid, 50 2g selenium, 15 mg zinc) or placebo was given twice daily. At HA, energy expenditure increased approximately 750 kcalId j1 and energy intake decreased approximately 550 kcalId j1 , resulting in a caloric deficit of approximately 1200–1500 kcalId j1 . At SL and HA day 1 (HA1) and day HA13, subjects exercised at 55% of V u O2peak until they expended approximately 1500 kcal. Blood samples were taken at rest, end of exercise, and 2, 4, and 20 h after exercise. Results: No differences were seen between groups in plasma IL-6, CRP, or TNF-! at rest or in response to exercise. For both groups, plasma IL-6 concentration was significantly higher at the end of exercise, 2, 4, and 20 h after exercise at HA1 compared with SL and HA13. Plasma CRP concentration was significantly elevated 20 h postexercise for both groups on HA1 compared to SL and HA13. TNF-! did not differ at rest or in response to exercise. Conclusion: Plasma IL-6 and CRP concentrations were elevated following exercise at high altitude on day 1, and antioxidant supplementation did not attenuate the rise in plasma IL-6 and CRP concentrations associated with hypoxia, exercise, and caloric deficit. Key Words: IL-6, TNF-!, C-REACTIVE PROTEIN, HYPOXIA, ENERGY DEFICIT

Objective To determine whether exercise intensity effects a change in body composition. Design/subjects Twelve untrained, moderately overfat, weight-stable women were randomly assigned to a high-intensity (80% Vo 2 max) or low-intensity (50% Vo 2 max) exercise group. Subjects trained four times per week for 12 weeks in monitored sessions, with a duration sufficient to expend 300 kcal. During this time, subjects were instructed to maintain their normal diet and activity patterns. Outcome measures Pretesting and posttesting included measurement of height, weight, body fat (via hydrostatic weighing), seven skinfold sites, seven circumference sites, and Vo 2 max. Statistical analyses Results were analyzed using the Student's t test and paired samples t test. Results Posttesting revealed no significant between-group differences for change in weight, percent body fat, fat mass, fat-free mass, sum of skinfold measurements, or sum of circumference measurements. Mean weight loss was 0.7lb for the high-intensity group ( P =.55) and 3.3lb for the low-intensity group ( P =.03). Hydrostatic data revealed that each group lost an identical amount of fat (5.0lb), but the high-intensity group gained more than twice as much fat-free mass (4.3 vs 1.8lb). The greater increase in fat-free mass by the high-intensity group explains why the low-intensity group had a greater absolute weight loss. Applications/conclusions This study suggests that fat loss is a function of energy expended rather than exercise intensity. Therefore, if fat loss is the goal and time is limited, persons should exercise safely at as high an intensity as tolerable to expend as much energy as possible during their allotted time. J Am Diet Assoc. 1995; 95:661-665 .

Background A sudden increase in exercise and energy expenditure is associated with an increase in protein turnover and nitrogen excretion. This study examined how a sudden increase in exercise-induced energy expenditure affected whole body protein metabolism and nitrogen balance in people of differing levels of aerobic fitness. We hypothesized that alterations in whole-body protein turnover would be attenuated, and nitrogen balance would be preserved, in individual with higher levels of aerobic fitness. Methods Eleven men, categorized as either having a lower (LOW-FIT; n = 5) or higher (FIT; n = 6) aerobic fitness level, completed a 4-d baseline period (BL) of an energy balance diet while maintaining usual physical activity level, followed by a 7-d intervention consisting of 1,000 kcal·d-1 increased energy expenditure via exercise (50–65% VO2peak). All volunteers consumed 0.9 g protein·kg-1·d-1 and total energy intake was adjusted to maintain energy balance throughout the 11-d study. Mean nitrogen balance (NBAL) was determined for BL, days 5–8 (EX1), and days 9–11 (EX2). Whole-body protein turnover was derived from phenylalanine and tyrosine kinetics assessed while fasting at rest on days 4, 7, and 12 using a priming dose of L-[ring-15N]tyrosine and a 4-h primed, continuous infusion of L-[15N]phenylalanine and L-[ring-2H4]tyrosine. Results A significant main effect of time indicated that NBAL increased over the course of the intervention; however, a group-by-time interaction was not observed. Although FIT demonstrated a lower net protein oxidation and higher net protein balance compared to LOW-FIT, neither the effect of time nor a group-by-time interaction was significant for Phe flux, net protein oxidation, or derived whole-body protein synthesis and net protein balance. Conclusion The absence of significant group-by-time interactions in protein metabolism (i.e., NBAL and whole-body protein turnover) between LOW-FIT and FIT males suggest that aerobic fitness level does not modulate protein "sparing" in response to an unaccustomed increase in energy expenditure.