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Volek JS, Kackley ML, Buga A. Nutritional Considerations During Major Weight Loss Therapy: Focus on Optimal Protein and a Low-Carbohydrate Dietary Pattern. Curr Nutr Rep 2024; 13:422-443. [PMID: 38814519 PMCID: PMC11327213 DOI: 10.1007/s13668-024-00548-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/01/2024] [Indexed: 05/31/2024]
Abstract
PURPOSE OF REVIEW Considering the high prevalence of obesity and related metabolic impairments in the population, the unique role nutrition has in weight loss, reversing metabolic disorders, and maintaining health cannot be overstated. Normal weight and well-being are compatible with varying dietary patterns, but for the last half century there has been a strong emphasis on low-fat, low-saturated fat, high-carbohydrate based approaches. Whereas low-fat dietary patterns can be effective for a subset of individuals, we now have a population where the vast majority of adults have excess adiposity and some degree of metabolic impairment. We are also entering a new era with greater access to bariatric surgery and approval of anti-obesity medications (glucagon-like peptide-1 analogues) that produce substantial weight loss for many people, but there are concerns about disproportionate loss of lean mass and nutritional deficiencies. RECENT FINDINGS No matter the approach used to achieve major weight loss, careful attention to nutritional considerations is necessary. Here, we examine the recent findings regarding the importance of adequate protein to maintain lean mass, the rationale and evidence supporting low-carbohydrate and ketogenic dietary patterns, and the potential benefits of including exercise training in the context of major weight loss. While losing and sustaining weight loss has proven challenging, we are optimistic that application of emerging nutrition science, particularly personalized well-formulated low-carbohydrate dietary patterns that contain adequate protein (1.2 to 2.0 g per kilogram reference weight) and achieve the beneficial metabolic state of euketonemia (circulating ketones 0.5 to 5 mM), is a promising path for many individuals with excess adiposity.
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Affiliation(s)
- Jeff S Volek
- Department of Human Sciences, The Ohio State University, 305 Annie & John Glenn Ave, Columbus, OH, 43210, USA.
| | - Madison L Kackley
- Department of Human Sciences, The Ohio State University, 305 Annie & John Glenn Ave, Columbus, OH, 43210, USA
| | - Alex Buga
- Department of Human Sciences, The Ohio State University, 305 Annie & John Glenn Ave, Columbus, OH, 43210, USA
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Berryman CE, McClung HL, Sepowitz JJ, Gaffney‐Stomberg E, Ferrando AA, McClung JP, Pasiakos SM. Testosterone status following short-term, severe energy deficit is associated with fat-free mass loss in U.S. Marines. Physiol Rep 2022; 10:e15461. [PMID: 36117330 PMCID: PMC9483439 DOI: 10.14814/phy2.15461] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 08/19/2022] [Accepted: 08/23/2022] [Indexed: 06/15/2023] Open
Abstract
The objective of this study was to determine metabolic and physiological differences between males with low testosterone (LT) versus those with normal testosterone (NT) following a period of severe energy deficit. In this secondary analysis, 68 male US Marines (mean ± SD, 24.6 ± 2.4 y) were dichotomized by testosterone concentration (< or ≥ 10.5 nmol/L as determined from a single blood sample collected between 0600-0630 after an 8-10 h overnight fast by automated immunoassay) following 7 days of near complete starvation (~300 kcal consumed/d, ~85% energy deficit) during Survival, Evasion, Resistance, and Escape (SERE) training. Dietary intake was assessed before (PRE) SERE. Body composition (dual-energy x-ray absorptiometry and peripheral quantitative computed tomography) and whole-body protein turnover (15 N alanine) were assessed before (PRE) and after (POST) SERE. Mean testosterone concentrations decreased PRE (17.5 ± 4.7 nmol/L) to POST (9.8 ± 4.0 nmol/L, p < 0.0001). When volunteers were dichotomized by POST testosterone concentrations [NT (n = 24) 14.1 ± 3.4 vs. LT (n = 44): 7.5 ± 1.8 nmol/L, p < 0.0001], PRE BMI, total fat mass, trunk fat mass, and testosterone were greater and the diet quality score and total carbohydrate intake were lower in NT compared to LT (p ≤ 0.05). LT lost more fat-free mass and less fat mass, particularly in the trunk region, compared to NT following SERE (p-interaction≤0.044). Whole-body protein synthesis, net balance, and flux decreased and whole-body protein breakdown increased from PRE to POST in both groups (p-time ≤0.025). Following short-term, severe energy deficit, Marines who exhibited low testosterone had greater fat-free mass loss than those who maintained normal testosterone concentrations. Altering body composition and dietary strategies prior to physical training that elicits severe energy deficit may provide an opportunity to attenuate post-training decrements in testosterone and its associated effects (e.g., loss of lean mass, performance declines, fatigue).
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Affiliation(s)
- Claire E. Berryman
- Military Nutrition DivisionUS Army Research Institute of Environmental MedicineNatickMassachusettsUSA
- Oak Ridge Institute for Science and EducationBelcampMarylandUSA
- Department of Nutrition and Integrative PhysiologyFlorida State UniversityTallahasseeFloridaUSA
| | - Holly L. McClung
- Military Nutrition DivisionUS Army Research Institute of Environmental MedicineNatickMassachusettsUSA
| | - John J. Sepowitz
- Military Nutrition DivisionUS Army Research Institute of Environmental MedicineNatickMassachusettsUSA
| | - Erin Gaffney‐Stomberg
- Military Performance DivisionU.S. Army Research Institute of Environmental MedicineNatickMassachusettsUSA
| | - Arny A. Ferrando
- Department of Geriatrics, The Center for Translational Research in Aging & LongevityDonald W. Reynolds Institute of Aging, University of Arkansas for Medical SciencesLittle RockArkansasUSA
| | - James P. McClung
- Military Nutrition DivisionUS Army Research Institute of Environmental MedicineNatickMassachusettsUSA
| | - Stefan M. Pasiakos
- Military Performance DivisionU.S. Army Research Institute of Environmental MedicineNatickMassachusettsUSA
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Varanoske AN, Harris MN, Hebert C, Howard EE, Johannsen NM, Heymsfield SB, Greenway FL, Margolis LM, Lieberman HR, Church DD, Ferrando AA, Rood JC, Pasiakos SM. Effects of testosterone undecanoate on performance during multi-stressor military operations: A trial protocol for the Optimizing Performance for Soldiers II study. Contemp Clin Trials Commun 2021; 23:100819. [PMID: 34278044 PMCID: PMC8264529 DOI: 10.1016/j.conctc.2021.100819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 06/15/2021] [Accepted: 07/02/2021] [Indexed: 11/22/2022] Open
Abstract
Background Previously, young males administered 200 mg/week of testosterone enanthate during 28 days of energy deficit (EDef) gained lean mass and lost less total mass than controls (Optimizing Performance for Soldiers I study, OPS I). Despite that benefit, physical performance deteriorated similarly in both groups. However, some experimental limitations may have precluded detection of performance benefits, as performance measures employed lacked military relevance, and the EDef employed did not elicit the magnitude of stress typically experienced by Soldiers conducting operations. Additionally, the testosterone administered required weekly injections, elicited supra-physiological concentrations, and marked suppression of endogenous testosterone upon cessation. Therefore, this follow-on study will address those limitations and examine testosterone's efficacy for preserving Solder performance during strenuous operations. Methods In OPS II, 32 males will participate in a randomized, placebo-controlled, double-blind trial. After baseline testing, participants will be administered either testosterone undecanoate (750 mg) or placebo before completing four consecutive, 5-day cycles simulating a multi-stressor, sustained military operation (SUSOPS). SUSOPS will consist of two low-stress days (1000 kcal/day exercise-induced EDef; 8 h/night sleep), followed by three high-stress days (3000 kcal/day and 4 h/night). A 23-day recovery period will follow SUSOPS. Military relevant physical performance is the primary outcome. Secondary outcomes include 4-comparment body composition, muscle and whole-body protein turnover, intramuscular mechanisms, biochemistries, and cognitive function/mood. Conclusions OPS II will determine if testosterone undecanoate safely enhances performance, while attenuating muscle and total mass loss, without impairing cognitive function, during and in recovery from SUSOPS. Trial Registration ClinicalTrials.gov Identifier: NCT04120363.
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Key Words
- Anabolism
- And hypogonadism
- BIA, bioelectrical impedance analysis
- D2O, deuterium
- DSMB, data and safety monitoring board
- DXA, dual-energy x-ray absorptiometry
- ECW, extracellular water
- EDef, energy deficit
- EIEE, exercise-induced energy expenditure
- Energy deficit
- Exercise
- FBR, fractional breakdown rate
- FFM, fat-free mass
- FSR, fractional synthetic rate
- HR, heart rate
- HRR, heart rate reserve
- ICW, intracellular water
- ID, identification
- IRB, Institutional Review Board
- MRE, Meal
- Optimizing Performance for Soldiers Trial I, OPS II
- Optimizing Performance for Soldiers Trial II, PAR-Q+
- Pennington Biomedical Research Center, PLA
- Physical Activity Readiness Questionnaire+, PB
- Ready-to-Eat, OPS I
- Skeletal muscle
- Sleep deprivation
- TBW, total body water
- TDEE, total daily energy expenditure
- TDEI, total daily energy intake
- TEST, testosterone experimental group
- VO2max, maximal cardiorespiratory fitness
- VO2peak, peak oxygen uptake
- WBGT, wet bulb globe temperature
- placebo experimental group, PS
- protein breakdown, PBRC
- protein synthesis, Q
- ratings of perceived exertion, SUSOPS
- repetition maximum, RNA
- respiratory exchange ratio, RM
- ribonucleic acid, RPE
- sustained, multi-stressor military operations
- whole-body nitrogen flux, RER
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Affiliation(s)
- Alyssa N Varanoske
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA, USA.,Oak Ridge Institute for Science and Education, Oak Ridge, TN, USA
| | - Melissa N Harris
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA
| | - Callie Hebert
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA
| | - Emily E Howard
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA, USA.,Oak Ridge Institute for Science and Education, Oak Ridge, TN, USA
| | - Neil M Johannsen
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA
| | - Steven B Heymsfield
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA
| | - Frank L Greenway
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA
| | - Lee M Margolis
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA, USA
| | - Harris R Lieberman
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA, USA
| | - David D Church
- Department of Geriatrics, Donald W. Reynolds Institute on Aging, Center for Translational Research in Aging & Longevity, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Arny A Ferrando
- Department of Geriatrics, Donald W. Reynolds Institute on Aging, Center for Translational Research in Aging & Longevity, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Jennifer C Rood
- Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA, USA
| | - Stefan M Pasiakos
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA, USA
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Nutritional Practice and Nitrogen Balance in Elite Japanese Swimmers during a Training Camp. Sports (Basel) 2021; 9:sports9020017. [PMID: 33494249 PMCID: PMC7909811 DOI: 10.3390/sports9020017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 01/08/2021] [Accepted: 01/18/2021] [Indexed: 11/17/2022] Open
Abstract
The protein requirement in athletes increases as a result of exercise-induced changes in protein metabolism. In addition, the frequency, quantity, and quality (i.e., leucine content) of the protein intake modulates the protein metabolism. Thus, this study aimed to investigate whether nutritional practice (particularly, protein and amino acid intake at each eating occasion) meets the protein needs required to achieve zero nitrogen balance in elite swimmers during a training camp. Eight elite swimmers (age 21.9 ± 2.3 years, body weight 64.2 ± 7.1 kg, sex M:2 F:6) participated in a four-day study. The nitrogen balance was calculated from the dietary nitrogen intake and urinary nitrogen excretion. The amino acid intake was divided over six eating occasions. The nitrogen balance was found to be positive (6.7 ± 3.1 g N/day, p < 0.05) with protein intake of 2.96 ± 0.74 g/kg/day. The frequency and quantity of leucine and the protein intake were met within the recommended range established by the International Society of Sports Nutrition. Thus, a protein intake of 2.96 g/kg/day with a well-designated pattern (i.e., frequency throughout the day, as well as quantity and quality) of protein and amino acid intake may satisfy the increased need for protein in an elite swimmer.
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Hirsch KR, Greenwalt CE, Saylor HE, Gould LM, Harrison CH, Brewer GJ, Blue MNM, Ferrando AA, Huffman KM, Mayer‐Davis EJ, Ryan ED, Smith‐Ryan AE. High-intensity interval training and essential amino acid supplementation: Effects on muscle characteristics and whole-body protein turnover. Physiol Rep 2021; 9:e14655. [PMID: 33369879 PMCID: PMC7769174 DOI: 10.14814/phy2.14655] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 09/23/2020] [Accepted: 10/29/2020] [Indexed: 12/15/2022] Open
Abstract
The purpose of this study was to compare the independent and combined effects of high-intensity interval training (HIIT) and essential amino acids (EAA) on lean mass, muscle characteristics of the quadriceps, and 24-hr whole-body protein turnover (WBPT) in overweight and obese adults. An exploratory aim was to evaluate potential modulatory effects of sex. Sixty-six adults (50% female; Age: 36.7 ± 6.0 yrs; %BF: 36.0 ± 7.8%) were assigned to 8 wks of: (a) HIIT, 2 days/wk; (b) EAA supplementation, 3.6 g twice daily; (c) HIIT + EAA; or (d) control. At baseline, 4 wks, and 8 wks, total body, thigh LM and muscle characteristics were measured via dual-energy x-ray absorptiometry and B-mode ultrasound, respectively. In a subsample, changes in WBPT was measured using [N15 ]alanine. Differences between groups were assessed using linear mixed models adjusted for baseline values, followed by 95% confidence intervals on adjusted mean change scores (Δ). HIIT and HIIT + EAA improved thigh LM (Δ: +0.17 ± 0.05 kg [0.08, 0.27]; +0.22 ± 0.05 kg [0.12,0.31]) and vastus lateralis cross-sectional area (Δ: +2.73 ± 0.52 cm2 [1.69,3.77]; +2.64 ± 0.53 cm2 [1.58,3.70]), volume (Δ: +54.50 ± 11.69 cm3 [31.07, 77.92]; +62.39 ± 12.05 cm3 [38.26, 86.52]), and quality (Δ: -5.46 ± 2.68a.u. [-10.84, -0.09]; -7.97 ± 2.76a.u.[-13.49, -2.45]). Protein synthesis, breakdown, and flux were greater with HIIT + EAA and EAA compared to HIIT (p < .05). Sex differences were minimal. Compared to women, men tended to respond more to HIIT, with or without EAA. For women, responses were greater with HIIT + EAA than HIIT. In overweight and obese adults, 8 weeks of HIIT, with or without EAA, improved thigh LM size and quality; EAA may enhance muscular adaptation via increases in protein turnover, supporting greater improvements in muscular size and quality.
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Affiliation(s)
- Katie R. Hirsch
- Applied Physiology LaboratoryDepartment of Exercise and Sport ScienceUniversity of North Carolina at Chapel HillChapel HillNCUSA
- Human Movement Science CurriculumDepartment of Allied Health ScienceUniversity of North Carolina at Chapel HillChapel HillNCUSA
- Department of GeriatricsDonald W. Reynolds Institute on AgingCenter for Translational Research in Aging & LongevityUniversity of Arkansas for Medical SciencesLittle RockARUSA
| | - Casey E. Greenwalt
- Applied Physiology LaboratoryDepartment of Exercise and Sport ScienceUniversity of North Carolina at Chapel HillChapel HillNCUSA
| | - Hannah E. Saylor
- Applied Physiology LaboratoryDepartment of Exercise and Sport ScienceUniversity of North Carolina at Chapel HillChapel HillNCUSA
- Human Movement Science CurriculumDepartment of Allied Health ScienceUniversity of North Carolina at Chapel HillChapel HillNCUSA
| | - Lacey M. Gould
- Applied Physiology LaboratoryDepartment of Exercise and Sport ScienceUniversity of North Carolina at Chapel HillChapel HillNCUSA
| | - Courtney H. Harrison
- Applied Physiology LaboratoryDepartment of Exercise and Sport ScienceUniversity of North Carolina at Chapel HillChapel HillNCUSA
| | - Gabrielle J. Brewer
- Applied Physiology LaboratoryDepartment of Exercise and Sport ScienceUniversity of North Carolina at Chapel HillChapel HillNCUSA
| | - Malia N. M. Blue
- Applied Physiology LaboratoryDepartment of Exercise and Sport ScienceUniversity of North Carolina at Chapel HillChapel HillNCUSA
- Human Movement Science CurriculumDepartment of Allied Health ScienceUniversity of North Carolina at Chapel HillChapel HillNCUSA
| | - Arny A. Ferrando
- Department of GeriatricsDonald W. Reynolds Institute on AgingCenter for Translational Research in Aging & LongevityUniversity of Arkansas for Medical SciencesLittle RockARUSA
| | - Kim M. Huffman
- Duke Molecular Physiology InstituteDuke UniversityDurhamNCUSA
- Department of MedicineDuke University School of MedicineDurhamNCUSA
| | - Elizabeth J. Mayer‐Davis
- Department of NutritionGillings School of Public HealthUniversity of North Carolina at Chapel Hill Chapel HillNCUSA
- Department of MedicineUniversity of North CarolinaChapel HillNCUSA
| | - Eric D. Ryan
- Human Movement Science CurriculumDepartment of Allied Health ScienceUniversity of North Carolina at Chapel HillChapel HillNCUSA
- Neuromuscular Assessment LaboratoryDepartment of Exercise and Sport ScienceUniversity of North Carolina at Chapel HillChapel HillNCUSA
| | - Abbie E. Smith‐Ryan
- Applied Physiology LaboratoryDepartment of Exercise and Sport ScienceUniversity of North Carolina at Chapel HillChapel HillNCUSA
- Human Movement Science CurriculumDepartment of Allied Health ScienceUniversity of North Carolina at Chapel HillChapel HillNCUSA
- Department of NutritionGillings School of Public HealthUniversity of North Carolina at Chapel Hill Chapel HillNCUSA
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Exercise Mitigates the Loss of Muscle Mass by Attenuating the Activation of Autophagy during Severe Energy Deficit. Nutrients 2019; 11:nu11112824. [PMID: 31752260 PMCID: PMC6893734 DOI: 10.3390/nu11112824] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 10/30/2019] [Accepted: 11/14/2019] [Indexed: 01/07/2023] Open
Abstract
The loss of skeletal muscle mass with energy deficit is thought to be due to protein breakdown by the autophagy-lysosome and the ubiquitin-proteasome systems. We studied the main signaling pathways through which exercise can attenuate the loss of muscle mass during severe energy deficit (5500 kcal/day). Overweight men followed four days of caloric restriction (3.2 kcal/kg body weight day) and prolonged exercise (45 min of one-arm cranking and 8 h walking/day), and three days of control diet and restricted exercise, with an intra-subject design including biopsies from muscles submitted to distinct exercise volumes. Gene expression and signaling data indicate that the main catabolic pathway activated during severe energy deficit in skeletal muscle is the autophagy-lysosome pathway, without apparent activation of the ubiquitin-proteasome pathway. Markers of autophagy induction and flux were reduced by exercise primarily in the muscle submitted to an exceptional exercise volume. Changes in signaling are associated with those in circulating cortisol, testosterone, cortisol/testosterone ratio, insulin, BCAA, and leucine. We conclude that exercise mitigates the loss of muscle mass by attenuating autophagy activation, blunting the phosphorylation of AMPK/ULK1/Beclin1, and leading to p62/SQSTM1 accumulation. This includes the possibility of inhibiting autophagy as a mechanism to counteract muscle loss in humans under severe energy deficit.
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Gaston AF, Marti Peiro A, Hapkova I, Durand F. Exploring physiological parameters in ski mountaineering during world cup races. INT J PERF ANAL SPOR 2019. [DOI: 10.1080/24748668.2019.1597399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Anne-Fleur Gaston
- Laboratoire Européen Performance Santé Altitude, Université de Perpignan Via Domitia, Font-Romeu, France
- Unité de Physiologie des Exercices et Activités en Conditions Extrêmes, Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, France
| | - Adrià Marti Peiro
- Laboratoire Européen Performance Santé Altitude, Université de Perpignan Via Domitia, Font-Romeu, France
- Nässjö Basket, Nässjö, Sweden
| | - Ilona Hapkova
- Laboratoire Européen Performance Santé Altitude, Université de Perpignan Via Domitia, Font-Romeu, France
- ECOWAS Campus, Lomé, Togo
| | - Fabienne Durand
- Laboratoire Européen Performance Santé Altitude, Université de Perpignan Via Domitia, Font-Romeu, France
- Catedra de Medicina de Muntanya i del Medi Natural i de Simulacio Clinica, Universitat de Girona, Girona, Spain
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8
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Receno CN, Liang C, Korol DL, Atalay M, Heffernan KS, Brutsaert TD, DeRuisseau KC. Effects of Prolonged Dietary Curcumin Exposure on Skeletal Muscle Biochemical and Functional Responses of Aged Male Rats. Int J Mol Sci 2019; 20:E1178. [PMID: 30866573 PMCID: PMC6429120 DOI: 10.3390/ijms20051178] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 02/28/2019] [Accepted: 03/03/2019] [Indexed: 12/30/2022] Open
Abstract
Oxidative stress resulting from decreased antioxidant protection and increased reactive oxygen and nitrogen species (RONS) production may contribute to muscle mass loss and dysfunction during aging. Curcumin is a phenolic compound shown to upregulate antioxidant defenses and directly quench RONS in vivo. This study determined the impact of prolonged dietary curcumin exposure on muscle mass and function of aged rats. Thirty-two-month-old male F344xBN rats were provided a diet with or without 0.2% curcumin for 4 months. The groups included: ad libitum control (CON; n = 18); 0.2% curcumin (CUR; n = 18); and pair-fed (PAIR; n = 18) rats. CUR rats showed lower food intake compared to CON, making PAIR a suitable comparison group. CUR rats displayed larger plantaris mass and force production (vs. PAIR). Nuclear fraction levels of nuclear factor erythroid-2 related-factor-2 were greater, and oxidative macromolecule damage was lower in CUR (vs. PAIR). There were no significant differences in measures of antioxidant status between any of the groups. No difference in any measure was observed between CUR and CON rats. Thus, consumption of curcumin coupled with reduced food intake imparted beneficial effects on aged skeletal muscle. The benefit of curcumin on aging skeletal muscle should be explored further.
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Affiliation(s)
- Candace N Receno
- 201 Women's Building, Department of Exercise Science, Syracuse University, Syracuse, NY 13244, USA.
| | - Chen Liang
- 201 Women's Building, Department of Exercise Science, Syracuse University, Syracuse, NY 13244, USA.
| | - Donna L Korol
- 107 College Place, Department of Biology, Syracuse University, Syracuse, NY 13244, USA.
| | - Mustafa Atalay
- Yliopistonranta 1 E, Institute of Biomedicine, Physiology, University of Eastern Finland, P.O. Box 1627, 70211 Kuopio, Finland.
| | - Kevin S Heffernan
- 201 Women's Building, Department of Exercise Science, Syracuse University, Syracuse, NY 13244, USA.
| | - Tom D Brutsaert
- 201 Women's Building, Department of Exercise Science, Syracuse University, Syracuse, NY 13244, USA.
| | - Keith C DeRuisseau
- 201 Women's Building, Department of Exercise Science, Syracuse University, Syracuse, NY 13244, USA.
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9
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Matsuda T, Kato H, Suzuki H, Mizugaki A, Ezaki T, Ogita F. Within-Day Amino Acid Intakes and Nitrogen Balance in Male Collegiate Swimmers during the General Preparation Phase. Nutrients 2018; 10:E1809. [PMID: 30463354 PMCID: PMC6266158 DOI: 10.3390/nu10111809] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 11/08/2018] [Accepted: 11/16/2018] [Indexed: 11/16/2022] Open
Abstract
A higher protein intake is recommended for athletes compared to healthy non-exercising individuals. Additionally, the distribution and quality (i.e., leucine content) of the proteins consumed throughout the day should be optimized. This study aimed to determine the nitrogen balance and distribution of protein and amino acid intakes in competitive swimmers during the general preparation phase. Thirteen swimmers (age: 19.7 ± 1.0 years; VO₂max: 63.9 ± 3.7 mL·kg-1·min-1, mean ± standard deviation) participated in a five-day experimental training period. Nutrient intakes were assessed using dietary records. Nitrogen balance was calculated from the daily protein intake and urinary nitrogen excretion. The intake amounts of amino acids and protein at seven eating occasions were determined. The average and population-safe intakes for zero nitrogen balance were estimated at 1.43 and 1.92 g·kg-1·day-1, respectively. The intake amounts of protein and leucine at breakfast, lunch, and dinner satisfied current guidelines for the maximization of muscle protein synthesis, but not in the other four occasions. The population-safe protein intake level in competitive swimmers was in the upper range (i.e., 1.2⁻2.0 g·kg-1·day-1) of the current recommendations for athletes. The protein intake distribution and quality throughout the day may be suboptimal for the maximization of the skeletal muscle adaptive response to training.
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Affiliation(s)
- Takeshi Matsuda
- Department of Sports and Life Sciences, National Institute of Fitness and Sports, 1 Shiromizu-cho, Kanoya, Kagoshima 891-2393, Japan.
| | - Hiroyuki Kato
- Frontier Research Laboratories, Institute for Innovation, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki, Kanagawa 210-8681, Japan.
- Olympic and Paralympic Promotional Office, Ajinomoto Co., Inc., 1-15-1 Kyobashi, Tokyo 210-8681, Japan.
| | - Haruka Suzuki
- Olympic and Paralympic Promotional Office, Ajinomoto Co., Inc., 1-15-1 Kyobashi, Tokyo 210-8681, Japan.
| | - Ami Mizugaki
- Frontier Research Laboratories, Institute for Innovation, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki, Kanagawa 210-8681, Japan.
- Olympic and Paralympic Promotional Office, Ajinomoto Co., Inc., 1-15-1 Kyobashi, Tokyo 210-8681, Japan.
| | - Takahiko Ezaki
- Olympic and Paralympic Promotional Office, Ajinomoto Co., Inc., 1-15-1 Kyobashi, Tokyo 210-8681, Japan.
| | - Futoshi Ogita
- Department of Sports and Life Sciences, National Institute of Fitness and Sports, 1 Shiromizu-cho, Kanoya, Kagoshima 891-2393, Japan.
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10
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Berryman CE, Young AJ, Karl JP, Kenefick RW, Margolis LM, Cole RE, Carbone JW, Lieberman HR, Kim IY, Ferrando AA, Pasiakos SM. Severe negative energy balance during 21 d at high altitude decreases fat-free mass regardless of dietary protein intake: a randomized controlled trial. FASEB J 2018; 32:894-905. [PMID: 29066613 DOI: 10.1096/fj.201700915r] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In this 2-phase randomized controlled study, we examined whether consuming a higher-protein (HP) diet would attenuate fat-free mass (FFM) loss during energy deficit (ED) at high altitude (HA) in 17 healthy males (mean ± sd: 23 ± 6 yr; 82 ± 14 kg). During phase 1 at sea level (SL, 55 m), participants consumed a eucaloric diet providing standard protein (SP; 1.0 g protein/kg,) for 21 d. During phase 2, participants resided at HA (4300 m) for 22 d and were randomly assigned to either an SP or HP (2.0 g protein/kg) diet designed to elicit a 40% ED. Body composition, substrate oxidation, and postabsorptive whole-body protein kinetics were measured. Participants were weight stable during SL and lost 7.9 ± 1.9 kg ( P < 0.01) during HA, regardless of dietary protein intake. Decrements in whole-body FFM (3.6 ± 2.4 kg) and fat mass (3.6 ± 1.3 kg) were not different between SP and HP. HP oxidized 0.95 ± 0.32 g protein/kg per day more than SP and whole-body net protein balance was more negative for HP than for SP ( P < 0.01). Based on changes in body energy stores, the overall ED was 70% (-1849 ± 511 kcal/d, no group differences). Consuming an HP diet did not protect FFM during severe ED at HA.-Berryman, C. E., Young, A. J., Karl, J. P., Kenefick, R. W., Margolis, L. M., Cole, R. E., Carbone, J. W., Lieberman, H. R., Kim, I.-Y., Ferrando, A. A., Pasiakos, S. M. Severe negative energy balance during 21 d at high altitude decreases fat-free mass regardless of dietary protein intake: a randomized controlled trial.
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Affiliation(s)
- Claire E Berryman
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine (USARIEM), Natick, Massachusetts, USA.,Oak Ridge Institute for Science and Education, Belcamp, Maryland, USA
| | - Andrew J Young
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine (USARIEM), Natick, Massachusetts, USA.,Oak Ridge Institute for Science and Education, Belcamp, Maryland, USA
| | - J Philip Karl
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine (USARIEM), Natick, Massachusetts, USA
| | - Robert W Kenefick
- Thermal Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine (USARIEM), Natick, Massachusetts, USA
| | - Lee M Margolis
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine (USARIEM), Natick, Massachusetts, USA.,Oak Ridge Institute for Science and Education, Belcamp, Maryland, USA
| | - Renee E Cole
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine (USARIEM), Natick, Massachusetts, USA
| | - John W Carbone
- Oak Ridge Institute for Science and Education, Belcamp, Maryland, USA.,School of Health Sciences, Eastern Michigan University, Ypsilanti, Michigan, USA
| | - Harris R Lieberman
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine (USARIEM), Natick, Massachusetts, USA
| | - Il-Young Kim
- Department of Geriatrics, Center for Translational Research in Aging and Longevity, Donald W. Reynolds Institute on Aging, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Arny A Ferrando
- Department of Geriatrics, Center for Translational Research in Aging and Longevity, Donald W. Reynolds Institute on Aging, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Stefan M Pasiakos
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine (USARIEM), Natick, Massachusetts, USA
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A 7-day high protein hypocaloric diet promotes cellular metabolic adaptations and attenuates lean mass loss in healthy males. CLINICAL NUTRITION EXPERIMENTAL 2017. [DOI: 10.1016/j.yclnex.2017.05.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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12
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Margolis LM, Rivas DA, Pasiakos SM, McClung JP, Ceglia L, Fielding RA. Upregulation of circulating myomiR following short-term energy restriction is inversely associated with whole body protein synthesis. Am J Physiol Regul Integr Comp Physiol 2017; 313:R298-R304. [PMID: 28659285 DOI: 10.1152/ajpregu.00054.2017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 06/22/2017] [Accepted: 06/26/2017] [Indexed: 01/05/2023]
Abstract
The objective of the present investigation was to determine whether energy restriction (ER) influences expression of skeletal muscle-specific microRNA (miRNA) in circulation (c-myomiR) and whether changes in c-myomiR are associated with rates of whole body protein synthesis. Sixteen older (64 ± 2 yr) overweight (28.5 ± 1.2 kg/m2) men enrolled in this 35-day controlled feeding trial. A 7-day weight maintenance (WM) period was followed by 28 days of 30% ER. Whole body protein turnover was determined from [15N]glycine enrichments in 24-h urine collections, and c-myomiR (miR-1-3p, miR-133a-3p, miR-133b, and miR-206) expression was assessed from serum samples by RT-quantitative PCR upon completion of the WM and ER periods. Participants lost 4.4 ± 0.3 kg body mass during ER (P < 0.05). After 28 days of ER, miR-133a and miR-133b expression was upregulated (P < 0.05) compared with WM. When all four c-myomiR were grouped as c-myomiR score (sum of the median fold change of all myomiR), overall expression of c-myomiR was higher (P < 0.05) at ER than WM. Backward linear regression analysis of whole body protein synthesis and breakdown and carbohydrate, fat, and protein oxidation determined protein synthesis to be the strongest predictor of c-myomiR score. An inverse association (P < 0.05) was observed with ER c-myomiR score and whole body protein synthesis (r = -0.729, r2 = -0.530). Findings from the present investigation provide evidence that upregulation of c-myomiR expression profiles in response to short-term ER is associated with lower rates of whole body protein synthesis.
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Affiliation(s)
- Lee M Margolis
- Nutrition, Exercise, Physiology, and Sarcopenia Laboratory, United States Department of Agriculture Jean Mayer Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts
| | - Donato A Rivas
- Nutrition, Exercise, Physiology, and Sarcopenia Laboratory, United States Department of Agriculture Jean Mayer Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts
| | - Stefan M Pasiakos
- Military Nutrition Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - James P McClung
- Military Nutrition Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Lisa Ceglia
- Bone Metabolism Laboratory, United States Department of Agriculture Jean Mayer Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts; and.,Division of Endocrinology, Diabetes, and Metabolism, Tufts Medical Center, Boston, Massachusetts
| | - Roger A Fielding
- Nutrition, Exercise, Physiology, and Sarcopenia Laboratory, United States Department of Agriculture Jean Mayer Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts;
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13
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Berryman CE, Sepowitz JJ, McClung HL, Lieberman HR, Farina EK, McClung JP, Ferrando AA, Pasiakos SM. Supplementing an energy adequate, higher protein diet with protein does not enhance fat-free mass restoration after short-term severe negative energy balance. J Appl Physiol (1985) 2017; 122:1485-1493. [PMID: 28385919 DOI: 10.1152/japplphysiol.01039.2016] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 03/20/2017] [Accepted: 03/31/2017] [Indexed: 11/22/2022] Open
Abstract
Negative energy balance during military operations can be severe and result in significant reductions in fat-free mass (FFM). Consuming supplemental high-quality protein following such military operations may accelerate restoration of FFM. Body composition (dual-energy X-ray absorptiometry) and whole body protein turnover (single-pool [15N]alanine method) were determined before (PRE) and after 7 days (POST) of severe negative energy balance during military training in 63 male US Marines (means ± SD, 25 ± 3 yr, 84 ± 9 kg). After POST measures were collected, volunteers were randomized to receive higher protein (HIGH: 1,103 kcal/day, 133 g protein/day), moderate protein (MOD: 974 kcal/day, 84 g protein/day), or carbohydrate-based low protein control (CON: 1,042 kcal/day, 7 g protein/day) supplements, in addition to a self-selected, ad libitum diet, for the 27-day intervention (REFED). Measurements were repeated POST-REFED. POST total body mass (TBM; -5.8 ± 1.0 kg, -7.0%), FFM (-3.1 ± 1.6 kg, -4.7%), and net protein balance (-1.7 ± 1.1 g protein·kg-1·day-1) were lower and proteolysis (1.1 ± 1.9 g protein·kg-1·day-1) was higher compared with PRE (P < 0.05). Self-selected, ad libitum dietary intake during REFED was similar between groups (3,507 ± 730 kcal/day, 2.0 ± 0.5 g protein·kg-1·day-1). However, diets differed by protein intake due to supplementation (CON: 2.0 ± 0.4, MOD: 3.2 ± 0.7, and HIGH: 3.5 ± 0.7 g·kg-1·day-1; P < 0.05) but not total energy (4,498 ± 725 kcal/day). All volunteers, independent of group assignment, achieved positive net protein balance (0.4 ± 1.0 g protein·kg-1·day-1) and gained TBM (5.9 ± 1.7 kg, 7.8%) and FFM (3.6 ± 1.8 kg, 5.7%) POST-REFED compared with POST (P < 0.05). Supplementing ad libitum, energy-adequate, higher protein diets with additional protein may not be necessary to restore FFM after short-term severe negative energy balance.NEW & NOTEWORTHY This article demonstrates 1) the majority of physiological decrements incurred during military training (e.g., total and fat-free mass loss), with the exception of net protein balance, resolve and return to pretraining values after 27 days and 2) protein supplementation, in addition to an ad libitum, higher protein (~2.0 g·kg-1·day-1), energy adequate diet, is not necessary to restore fat-free mass following short-term severe negative energy balance.
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Affiliation(s)
- C E Berryman
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts.,Oak Ridge Institute for Science and Education, Belcamp, Maryland; and
| | - J J Sepowitz
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - H L McClung
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - H R Lieberman
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - E K Farina
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts.,Oak Ridge Institute for Science and Education, Belcamp, Maryland; and
| | - J P McClung
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - A A Ferrando
- Department of Geriatrics, Center for Translational Research in Aging and Longevity, Donald W. Reynolds Institute on Aging, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - S M Pasiakos
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts;
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Toth MJ, Matthews DE. Whole-Body Protein Metabolism in Chronic Heart Failure: Relationship to Anabolic and Catabolic Hormones. JPEN J Parenter Enteral Nutr 2017; 30:194-201. [PMID: 16639065 DOI: 10.1177/0148607106030003194] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Patients with chronic heart failure frequently experience profound wasting during the course of the disease, a condition termed cardiac cachexia. Although protein is the primary structural and functional component of most tissues, few studies have examined the effect of heart failure on protein metabolism. Moreover, no study has assessed the relationship of protein turnover to hormonal alterations thought to promote cachexia. Thus, our goal was to determine if whole-body protein metabolism is altered in heart failure patients and to assess the relationship of protein kinetics to circulating levels of anabolic and catabolic hormones. METHODS We measured whole-body protein metabolism using 13C-leucine, body composition, and circulating anabolic and catabolic hormone levels in 10 patients with chronic heart failure and 11 elderly controls. RESULTS No differences in leucine rate of appearance, oxidation, or nonoxidative disposal were noted between heart failure patients and controls. However, in a subgroup of patients characterized by increased resting energy expenditure for their metabolic body size (n = 4; > or = 20% above that predicted from fat-free mass), leucine rate of appearance (mean +/- SE; 146 +/- 6 micromol/min), an index of protein breakdown, tended to be higher compared with patients with normal resting energy expenditure (n = 5; 120 +/- 8 micromol/min) and controls (127 +/- 4 micromol/min; p = .06). Alterations in anabolic/catabolic hormone balance did not explain increased protein breakdown in this subgroup, and no correlations were found between hormone levels and protein breakdown in the heart failure group as a whole. In contrast, increased circulating interleukin-6 soluble receptor (r = 0.829; p < .01) and reduced insulin-like growth factor-I (r =-.751; p < .05) levels were related to greater rates of leucine oxidation in heart failure patients. CONCLUSION Our results demonstrate that, although increased protein turnover is not a generalized feature of heart failure, there is a subgroup of patients characterized by resting hypermetabolism and increased protein breakdown. Moreover, hormonal alterations related to the heart failure syndrome were related to increased protein oxidation.
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Affiliation(s)
- Michael J Toth
- Department of Medicine, Health Science Research Facility, University of Vermont, Burlington, Vermont 05405, USA.
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15
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Pasiakos SM. Metabolic advantages of higher protein diets and benefits of dairy foods on weight management, glycemic regulation, and bone. J Food Sci 2015; 80 Suppl 1:A2-7. [PMID: 25757894 DOI: 10.1111/1750-3841.12804] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 11/17/2014] [Accepted: 11/17/2014] [Indexed: 01/23/2023]
Abstract
The Inst. of Medicine and World Health Organization have determined that 0.8 to 0.83 g protein·kg(-1) ·d(-1) is the quantity of protein required to establish nitrogen balance in nearly all healthy individuals. However, consuming higher protein diets may be metabolically advantageous, particularly for overweight and obese adults attempting weight loss, and for physically active individuals such as athletes and military personnel. Studies have demonstrated that higher protein diets may spare lean body mass during weight loss, promote weight management, enhance glycemic regulation, and increase intestinal calcium absorption, which may result in long-term improvements in bone health. The extent to which higher protein diets are beneficial is largely attributed to the digestive and absorptive properties, and also to the essential amino acid (EAA) content of the protein. Proteins that are rapidly digested and absorbed likely contribute to the metabolic advantages conferred by consuming higher protein diets. The EAA profiles, as well as the digestive and absorptive properties of dairy proteins, such as whey protein and casein, are particularly advantageous because they facilitate a rapid, robust, and sustained delivery of EAAs to the periphery. This article reviews the scientific literature assessing metabolic advantages associated with higher protein diets on weight management, glycemic regulation, and bone, with emphasis given to studies evaluating the potential benefits associated with dairy.
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Affiliation(s)
- Stefan M Pasiakos
- Military Nutrition Div, US Army Research Inst. of Environmental Medicine, Natick, MA, U.S.A
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Smiles WJ, Areta JL, Coffey VG, Phillips SM, Moore DR, Stellingwerff T, Burke LM, Hawley JA, Camera DM. Modulation of autophagy signaling with resistance exercise and protein ingestion following short-term energy deficit. Am J Physiol Regul Integr Comp Physiol 2015; 309:R603-12. [DOI: 10.1152/ajpregu.00413.2014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 06/30/2015] [Indexed: 12/31/2022]
Abstract
Autophagy contributes to remodeling of skeletal muscle and is sensitive to contractile activity and prevailing energy availability. We investigated changes in targeted genes and proteins with roles in autophagy following 5 days of energy balance (EB), energy deficit (ED), and resistance exercise (REX) after ED. Muscle biopsies from 15 subjects (8 males, 7 females) were taken at rest following 5 days of EB [45 kcal·kg fat free mass (FFM)−1·day−1] and 5 days of ED (30 kcal·kg FFM−1·day−1). After ED, subjects completed a bout of REX and consumed either placebo (PLA) or 30 g whey protein (PRO) immediately postexercise. Muscle biopsies were obtained at 1 and 4 h into recovery in each trial. Resting protein levels of autophagy-related gene protein 5 (Atg5) decreased after ED compared with EB (∼23%, P < 0.001) and remained below EB from 1 to 4 h postexercise in PLA (∼17%) and at 1 h in PRO (∼18%, P < 0.05). In addition, conjugated Atg5 (cAtg12) decreased below EB in PLA at 4 h (∼20, P < 0.05); however, its values were increased above this time point in PRO at 4 h alongside increases in FOXO1 above EB (∼22–26%, P < 0.05). Notably, these changes were subsequent to increases in unc-51-like kinase 1Ser757 phosphorylation (∼60%) 1 h postexercise in PRO. No significant changes in gene expression of selected autophagy markers were found, but EGR-1 increased above ED and EB in PLA (∼417–864%) and PRO (∼1,417–2,731%) trials 1 h postexercise ( P < 0.001). Postexercise protein availability, compared with placebo, can selectively promote autophagic responses to REX in ED.
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Affiliation(s)
- William J. Smiles
- Mary MacKillop Institute for Health Research, Centre for Exercise and Nutrition, Australian Catholic University, Melbourne, Victoria, Australia
| | - José L. Areta
- Mary MacKillop Institute for Health Research, Centre for Exercise and Nutrition, Australian Catholic University, Melbourne, Victoria, Australia
| | - Vernon G. Coffey
- Bond Institute of Health and Sport and Faculty of Health Sciences and Medicine, Bond University, Queensland, Australia
| | - Stuart M. Phillips
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Daniel R. Moore
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
| | | | - Louise M. Burke
- Department of Sports Nutrition, Australian Institute of Sport, Canberra, Australia
| | - John A. Hawley
- Mary MacKillop Institute for Health Research, Centre for Exercise and Nutrition, Australian Catholic University, Melbourne, Victoria, Australia
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Donny M. Camera
- Mary MacKillop Institute for Health Research, Centre for Exercise and Nutrition, Australian Catholic University, Melbourne, Victoria, Australia
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Pasiakos SM, Margolis LM, Orr JS. Optimized dietary strategies to protect skeletal muscle mass during periods of unavoidable energy deficit. FASEB J 2014; 29:1136-42. [DOI: 10.1096/fj.14-266890] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 12/01/2014] [Indexed: 12/14/2022]
Affiliation(s)
- Stefan M. Pasiakos
- Military Nutrition DivisionU.S. Army Research Institute of Environmental MedicineNatickMassachusettsUSA
| | - Lee M. Margolis
- Military Nutrition DivisionU.S. Army Research Institute of Environmental MedicineNatickMassachusettsUSA
| | - Jeb S. Orr
- Military Nutrition DivisionU.S. Army Research Institute of Environmental MedicineNatickMassachusettsUSA
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Carbone JW, Pasiakos SM, Vislocky LM, Anderson JM, Rodriguez NR. Effects of short-term energy deficit on muscle protein breakdown and intramuscular proteolysis in normal-weight young adults. Appl Physiol Nutr Metab 2014; 39:960-8. [DOI: 10.1139/apnm-2013-0433] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effects of short-term energy deficit (ED) on direct measures of muscle proteolysis and the intracellular mechanisms by which muscle proteins are degraded at rest and following aerobic exercise are not well described. This study evaluated the effects of a short-term diet-induced ED, on muscle fractional breakdown rate (FBR), intramuscular 26S proteasome activity, caspase-3 activation, and PSMA2 and MAFbx expression at rest, in the postabsorptive state, and following a single bout of moderate aerobic exercise (45 min at 65% peak oxygen uptake). Six men and 4 women participated in two 10-day diet interventions: weight maintenance (WM) followed by ED (80% estimated energy requirements). Dietary protein (1.5 g·kg−1·day−1) intake was constant for WM and ED. Mixed muscle FBR, proteasome activity, and intracellular proteolytic factor expression were measured using stable isotope methodology, fluorescent enzyme activity assays, and Western blotting, respectively. Overall, FBR and caspase-3 activation increased 60% and 11%, respectively, in response to ED (P < 0.05), but were not influenced by exercise. During ED, 26S proteasome α-subunit PSMA2 expression was 25% higher (P < 0.05) after exercise compared with rest. Exercise did not influence PSMA2 expression during WM, and MAFbx expression and 26S proteasome activity were not affected by ED or exercise. These data illustrate the effects of short-term, moderate ED on muscle protein degradation. In the context of skeletal muscle integrity during weight loss interventions, this work demonstrates a need for further investigations aimed at mitigating muscle loss associated with energy deficit imposed for intentional reduction of total body weight.
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Affiliation(s)
- John W. Carbone
- School of Health Sciences, 312 Marshall Building, Eastern Michigan University, Ypsilanti, MI 48197, USA
| | - Stefan M. Pasiakos
- US Amy Research Institute of Environmental Medicine, Natick, MA 01760, USA
| | - Lisa M. Vislocky
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269, USA
| | | | - Nancy R. Rodriguez
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269, USA
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Cao JJ, Pasiakos SM, Margolis LM, Sauter ER, Whigham LD, McClung JP, Young AJ, Combs GF. Calcium homeostasis and bone metabolic responses to high-protein diets during energy deficit in healthy young adults: a randomized controlled trial. Am J Clin Nutr 2014; 99:400-7. [PMID: 24284444 DOI: 10.3945/ajcn.113.073809] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Although consuming dietary protein above current recommendations during energy deficit (ED) preserves lean body mass, concerns have been raised regarding the effects of high-protein diets on bone health. OBJECTIVE The objective was to determine whether calcium homeostasis and bone turnover are affected by high-protein diets during weight maintenance (WM) and ED. DESIGN In a randomized, parallel-design, controlled trial of 32 men and 7 women, volunteers were assigned diets providing protein at 0.8 [Recommended Dietary Allowance (RDA)], 1.6 (2 × RDA), or 2.4 (3 × RDA) g · kg(-1) · d(-1) for 31 d. Ten days of WM preceded 21 d of ED, during which total daily ED was 40%, achieved by reduced dietary energy intake (∼30%) and increased physical activity (∼10%). The macronutrient composition (protein g · kg(-1) · d(-1) and % fat) was held constant from WM to ED. Calcium absorption (ratio of (44)Ca to (42)Ca) and circulating indexes of bone turnover were determined at day 8 (WM) and day 29 (ED). RESULTS Regardless of energy state, mean (±SEM) urinary pH was lower (P < 0.05) at 2 × RDA (6.28 ± 0.05) and 3 × RDA (6.23 ± 0.06) than at the RDA (6.54 ± 0.06). However, protein had no effect on either urinary calcium excretion (P > 0.05) or the amount of calcium retained (P > 0.05). ED decreased serum insulin-like growth factor I concentrations and increased serum tartrate-resistant acid phosphatase and 25-hydroxyvitamin D concentrations (P < 0.01). Remaining markers of bone turnover and whole-body bone mineral density and content were not affected by either the protein level or ED (P > 0.05). CONCLUSION These data demonstrate that short-term consumption of high-protein diets does not disrupt calcium homeostasis and is not detrimental to skeletal integrity. This trial was registered at www.clinicaltrials.gov as NCT01292395.
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Affiliation(s)
- Jay J Cao
- USDA, Agricultural Research Service, Grand Forks Human Nutrition Research Center, Grand Forks, ND (JJC, LDW, and GFC); the Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, MA (SMP, LMM, JPM, and AJY); and the School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND (ERS)
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Effects on transcriptional regulation and lipid droplet characteristics in the liver of female juvenile pigs after early postnatal feed restriction and refeeding are dependent on birth weight. PLoS One 2013; 8:e76705. [PMID: 24260100 PMCID: PMC3834034 DOI: 10.1371/journal.pone.0076705] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 08/23/2013] [Indexed: 12/22/2022] Open
Abstract
Epidemiological and experimental data indicate that caloric restriction in early postnatal life may improve liver lipid metabolism in low birth weight individuals. The present study investigated transcriptional and metabolic responses to low (U) and normal (N) birth weight (d 75, T1) and postnatal feed restriction (R, 60% of controls, d 98, T2) followed by subsequent refeeding until d 131 of age (T3). Liver tissue studies were performed with a total of 42 female pigs which were born by multiparous German landrace sows. Overall, 194 genes were differentially expressed in the liver of U vs. N (T1) animals with roles in lipid metabolism. The total mean area and number of lipid droplets (LD) was about 4.6- and 3.7 times higher in U compared to N. In U, the mean LD size (µm2) was 24.9% higher. 3-week feed restriction reduced total mean area of LDs by 58.3 and 72.7% in U and N, respectively. A functional role of the affected genes in amino acid metabolism was additionally indicated. This was reflected by a 17.0% higher arginine concentration in the liver of UR animals (vs. NR). To evaluate persistency of effects, analyses were also done after refeeding period at T3. Overall, 4 and 22 genes show persistent regulation in U and N animals after 5 weeks of refeeding, respectively. These genes are involved in e.g. processes of lipid and protein metabolism and glucose homeostasis. Moreover, the recovery of total mean LD area in U and N animals back to the previous T1 level was observed. However, when compared to controls, the mean LD size was still reduced by 23.3% in UR, whereas it was increased in NR (+24.7%). The present results suggest that short-term postnatal feed restriction period programmed juvenile U animals for an increased rate of hepatic lipolysis in later life.
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Pasiakos SM, Cao JJ, Margolis LM, Sauter ER, Whigham LD, McClung JP, Rood JC, Carbone JW, Combs GF, Young AJ. Effects of high-protein diets on fat-free mass and muscle protein synthesis following weight loss: a randomized controlled trial. FASEB J 2013; 27:3837-47. [PMID: 23739654 DOI: 10.1096/fj.13-230227] [Citation(s) in RCA: 177] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The purpose of this work was to determine the effects of varying levels of dietary protein on body composition and muscle protein synthesis during energy deficit (ED). A randomized controlled trial of 39 adults assigned the subjects diets providing protein at 0.8 (recommended dietary allowance; RDA), 1.6 (2×-RDA), and 2.4 (3×-RDA) g kg(-1) d(-1) for 31 d. A 10-d weight-maintenance (WM) period was followed by a 21 d, 40% ED. Body composition and postabsorptive and postprandial muscle protein synthesis were assessed during WM (d 9-10) and ED (d 30-31). Volunteers lost (P<0.05) 3.2 ± 0.2 kg body weight during ED regardless of dietary protein. The proportion of weight loss due to reductions in fat-free mass was lower (P<0.05) and the loss of fat mass was higher (P<0.05) in those receiving 2×-RDA and 3×-RDA compared to RDA. The anabolic muscle response to a protein-rich meal during ED was not different (P>0.05) from WM for 2×-RDA and 3×-RDA, but was lower during ED than WM for those consuming RDA levels of protein (energy × protein interaction, P<0.05). To assess muscle protein metabolic responses to varied protein intakes during ED, RDA served as the study control. In summary, we determined that consuming dietary protein at levels exceeding the RDA may protect fat-free mass during short-term weight loss.
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Affiliation(s)
- Stefan M Pasiakos
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, 15 Kansas St., Bldg 42, Natick, MA 01760, USA.
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Arul D, Subramanian P. Circadian rhythms of plasma lipid and protein levels in daytime food-restricted rats. BIOL RHYTHM RES 2013. [DOI: 10.1080/09291016.2013.785696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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23
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Müller MJ, Bosy-Westphal A. Adaptive thermogenesis with weight loss in humans. Obesity (Silver Spring) 2013; 21:218-28. [PMID: 23404923 DOI: 10.1002/oby.20027] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Revised: 05/15/2012] [Accepted: 06/28/2012] [Indexed: 01/08/2023]
Abstract
UNLABELLED Adaptive thermogenesis (AT) with weight loss refers to underfeeding-associated fall in resting and non-resting energy expenditure (REE, non-REE); this is independent of body weight and body composition. In humans, the existence of AT was inconsistently shown and its clinical significance has been questioned. OBJECTIVES Discrepant findings are mainly due to different definitions of AT, the use of various and nonstandardized study protocols, and the limits of accuracy of methods to assess energy expenditure. With controlled underfeeding, AT takes more than 2 wk to develop. AT accounts to an average of 0.5 MJ (or 120 kcal) with a considerable between subject variance. DESIGN AND METHODS Low-sympathetic nervous system activity, 3,5,3'-tri-iodothyronine (T3) and leptin are likely to add to AT; however, the kinetic changes of their plasma levels with underfeeding differ from the time course of AT and controlled intervention studies substituting and titrating these hormones are rare in humans. AT in response to underfeeding is independent of thermogenesis in response to either diet or cold. Although fat-free mass (FFM) and, thus, liver, and skeletal muscle are considered as major sites of AT, cold-induced nonshivering thermogenesis relates to the metabolism of brown adipose tissue (BAT). In humans, diet-induced thermogenesis is related to postprandial substrate metabolism of FFM with a questionable role of BAT. Obviously, the REE component of AT differs from and its non-REE component with respect to organ contribution as well as mechanisms. Thus, AT cannot be considered as unique. CONCLUSIONS AT should be characterized based on individual components of daily energy expenditure, detailed body composition analyses, and mathematical modeling. The biological basis of AT as well as the influences of age, sex, obesity, stress, and inflammation remain to be established in humans.
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Affiliation(s)
- M J Müller
- Institut für Humanernährung und Lebensmittelkunde, Christian-Albrechts-Universität zu Kiel, Düsternbrooker Weg 17, 24105 Kiel, Germany.
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Carbone JW, McClung JP, Pasiakos SM. Skeletal muscle responses to negative energy balance: effects of dietary protein. Adv Nutr 2012; 3:119-26. [PMID: 22516719 PMCID: PMC3648712 DOI: 10.3945/an.111.001792] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Sustained periods of negative energy balance decrease body mass due to losses of both fat and skeletal muscle mass. Decreases in skeletal muscle mass are associated with a myriad of negative consequences, including suppressed basal metabolic rate, decreased protein turnover, decreased physical performance, and increased risk of injury. Decreases in skeletal muscle mass in response to negative energy balance are due to imbalanced rates of muscle protein synthesis and degradation. However, the underlying physiological mechanisms contributing to the loss of skeletal muscle during energy deprivation are not well described. Recent studies have demonstrated that consuming dietary protein at levels above the current recommended dietary allowance (0.8 g · kg(-1) · d(-1)) may attenuate the loss of skeletal muscle mass by affecting the intracellular regulation of muscle anabolism and proteolysis. However, the specific mechanism by which increased dietary protein spares skeletal muscle through enhanced molecular control of muscle protein metabolism has not been elucidated. This article reviews the available literature related to the effects of negative energy balance on skeletal muscle mass, highlighting investigations that assessed the influence of varying levels of dietary protein on skeletal muscle protein metabolism. Further, the molecular mechanisms that may contribute to the regulation of skeletal muscle mass in response to negative energy balance and alterations in dietary protein level are described.
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Affiliation(s)
- John W. Carbone
- School of Health Sciences, Eastern Michigan University, Ypsilanti, MI; and
| | - James P. McClung
- Military Nutrition Division, United States Army Research Institute of Environmental Medicine, Natick, MA
| | - Stefan M. Pasiakos
- Military Nutrition Division, United States Army Research Institute of Environmental Medicine, Natick, MA,To whom correspondence should be addressed: E-mail:
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Nutrigenetics and Nutrigenomics of Caloric Restriction. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 108:323-46. [DOI: 10.1016/b978-0-12-398397-8.00013-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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26
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Pasiakos SM, Vislocky LM, Carbone JW, Altieri N, Konopelski K, Freake HC, Anderson JM, Ferrando AA, Wolfe RR, Rodriguez NR. Acute energy deprivation affects skeletal muscle protein synthesis and associated intracellular signaling proteins in physically active adults. J Nutr 2010; 140:745-51. [PMID: 20164371 DOI: 10.3945/jn.109.118372] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
To date, few studies have characterized the influence of energy deprivation on direct measures of skeletal muscle protein turnover. In this investigation, we characterized the effect of an acute, moderate energy deficit (10 d) on mixed muscle fractional synthetic rate (FSR) and associated intracellular signaling proteins in physically active adults. Eight men and 4 women participated in a 20-d, 2-phase diet intervention study: weight maintenance (WM) and energy deficient (ED; approximately 80% of estimated energy requirements). Dietary protein (1.5 g x kg(-1) x d(-1)) and fat (approximately 30% of total energy) were constant for WM and ED. FSR and intracellular signaling proteins were measured on d 10 of both interventions using a primed, constant infusion of [(2)H(5)]-phenylalanine and Western blotting techniques, respectively. Participants lost approximately 1 kg body weight during ED (P < 0.0001). FSR was reduced approximately 19% (P < 0.05) for ED (0.06 +/- 0.01%/h) compared with WM (0.074 +/- 0.01%/h). Protein kinase B and eukaryotic initiation factor 4E binding protein 1 phosphorylation were lower (P < 0.05) during ED compared with WM. AMP activated protein kinase phosphorylation decreased (P < 0.05) over time regardless of energy status. These findings show that FSR and associated synthetic intracellular signaling proteins are downregulated in response to an acute, moderate energy deficit in physically active adults and provide a basis for future studies assessing the impact of prolonged, and perhaps more severe, energy restriction on skeletal muscle protein turnover.
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Affiliation(s)
- Stefan M Pasiakos
- Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269, USA
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Campbell WW, Haub MD, Wolfe RR, Ferrando AA, Sullivan DH, Apolzan JW, Iglay HB. Resistance training preserves fat-free mass without impacting changes in protein metabolism after weight loss in older women. Obesity (Silver Spring) 2009; 17:1332-9. [PMID: 19247271 PMCID: PMC4299870 DOI: 10.1038/oby.2009.2] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
This study assessed the effects of resistance training (RT) on energy restriction-induced changes in body composition, protein metabolism, and the fractional synthesis rate of mixed muscle proteins (FSRm) in postmenopausal, overweight women. Sixteen women (age 68 +/- 1 years, BMI 29 +/- 1 kg/m(2), mean +/- s.e.m.) completed a 16-week controlled diet study. Each woman consumed 1.0 g protein/kg/day. At baseline (weeks B1-B3) and poststudy (weeks RT12-RT13), energy intake matched each subject's need and during weeks RT1-RT11 was hypoenergetic by 2,092 kJ/day (500 kcal/day). From weeks RT1 to RT13, eight women performed RT 3 day/week (RT group) and eight women remained sedentary (SED group). RT did not influence the energy restriction-induced decrease in body mass (SED -5.8 +/- 0.6 kg; RT -5.0 +/- 0.2 kg) and fat mass (SED -4.1 +/- 0.9 kg; RT -4.7 +/- 0.5 kg). Fat free mass (FFM) and total body water decreased in SED (-1.6 +/- 0.4 and -2.1 +/- 0.5 kg) and were unchanged in RT (-0.3 +/- 0.4 and -0.4 +/- 0.7 kg) (group-by-time, P < or = 0.05 and P = 0.07, respectively). Protein-mineral mass did not change in either group (SED 0.4 +/- 0.2 kg; RT 0.1 +/- 0.4 kg). Nitrogen balance, positive at baseline (2.2 +/- 0.3 g N/day), was unchanged poststudy. After body mass loss, postabsorptive (PA) and postprandial (PP) leucine turnover, synthesis, and breakdown decreased. Leucine oxidation and balance were not changed. PA and total (PA + PP) FSRm in the vastus lateralis were higher after weight loss. RT did not influence these protein metabolism responses. In summary, RT helps older women preserve FFM during body mass loss. The comparable whole-body nitrogen retentions, leucine kinetics, and FSRm between groups are consistent with the lack of differential protein-mineral mass change.
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Affiliation(s)
- Wayne W Campbell
- Department of Foods and Nutrition, Purdue University, West Lafayette, Indiana, USA.
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28
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Ramsey JJ, Hagopian K. Energy expenditure and restriction of energy intake: could energy restriction alter energy expenditure in companion animals? J Nutr 2006; 136:1958S-1966S. [PMID: 16772468 DOI: 10.1093/jn/136.7.1958s] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The treatment of obesity in companion animals frequently focuses on restriction of energy intake. One important question with this treatment is whether dietary energy restriction (ER) produces a sustained decrease in mass-adjusted energy expenditure (EE), which prevents further weight loss and promotes rapid regain of body weight during lapses in dietary ER. This review summarizes studies that investigated the effects of dietary ER on EE at the whole-animal, organ, and cellular level. Whole-animal studies indicate that long-term dietary ER either decreases or does not affect mass-adjusted EE. The reason for this discrepancy between studies is not entirely clear, although analysis of data pooled from multiple studies suggests that a reduction in mass-adjusted EE with long-term ER would be observed if the sample size were sufficiently large and appropriate methods were used to adjust EE for body size. At the organ level, attempts were made to determine whether alterations in organ mass can entirely explain changes in EE with dietary ER. However, these studies were not conclusive, and it remains to be determined whether changes in EE exceed those that would be predicted from ER-induced alterations in organ mass. At the cellular level, there is evidence that dietary ER may induce sustained decreases in substrate oxidation, mitochondrial proton, and Na+-K+-ATPase activity in at least some tissues. These results are consistent with the idea that dietary ER may induce decreases in cellular EE. However, future studies integrating measurements at the whole-animal, organ, and cellular level will be required to determine definitively whether dietary ER produces sustained decreases in tissue or cellular EE.
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Affiliation(s)
- Jon J Ramsey
- Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
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Duggleby SL, Waterlow JC. The end-product method of measuring whole-body protein turnover: a review of published results and a comparison with those obtained by leucine infusion. Br J Nutr 2005; 94:141-53. [PMID: 16115347 DOI: 10.1079/bjn20051460] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The present review summarizes the results of all published papers on whole-body protein turnover in man measured by [15N]glycine and the end-product method using both urea and ammonia. It begins with a short account of the underlying assumptions and the justification for the use of [15N]glycine. The results are then compared with those of a large sample of measurements by the 'gold standard' precursor method with continuous infusion of [13C]leucine. The pros and cons of the two methods are compared and it is suggested that there is a place for further work by the less invasive end-product method, particularly for population studies of the genetic, environmental and functional determinants of whole-body rates of protein synthesis.
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Affiliation(s)
- S L Duggleby
- MRC Epidemiology Resource Centre, Southampton General Hospital, Southampton 5022 5A, UK
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30
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Friedlander AL, Braun B, Pollack M, MacDonald JR, Fulco CS, Muza SR, Rock PB, Henderson GC, Horning MA, Brooks GA, Hoffman AR, Cymerman A. Three weeks of caloric restriction alters protein metabolism in normal-weight, young men. Am J Physiol Endocrinol Metab 2005; 289:E446-55. [PMID: 15870104 DOI: 10.1152/ajpendo.00001.2005] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effects of prolonged caloric restriction (CR) on protein kinetics in lean subjects has not been investigated previously. The purpose of this study was to test the hypotheses that 21 days of CR in lean subjects would 1) result in significant losses of lean mass despite a suppression in leucine turnover and oxidation and 2) negatively impact exercise performance. Nine young, normal-weight men [23 +/- 5 y, 78.6 +/- 5.7 kg, peak oxygen consumption (Vo2 peak) 45.2 +/- 7.3 ml.kg(-1).min(-1), mean +/- SD] were underfed by 40% of the calories required to maintain body weight for 21 days and lost 3.8 +/- 0.3 kg body wt and 2.0 +/- 0.4 kg lean mass. Protein intake was kept at 1.2 g.kg(-1).day(-1). Leucine kinetics were measured using alpha-ketoisocaproic acid reciprocal pool model in the postabsorptive state during rest and 50 min of exercise (EX) at 50% of Vo2 peak). Body composition, basal metabolic rate (BMR), and exercise performance were measured throughout the intervention. At rest, leucine flux (approximately 131 micromol.kg(-1).h(-1)) and oxidation (R(ox); approximately 19 micromol.kg(-1).h(-1)) did not differ pre- and post-CR. During EX, leucine flux (129 +/- 6 vs. 121 +/- 6) and R(ox) (54 +/- 6 vs. 46 +/- 8) were lower after CR than they were pre-CR. Nitrogen balance was negative throughout the intervention ( approximately 3.0 g N/day), and BMR declined from 1,898 +/- 262 to 1,670 +/- 203 kcal/day. Aerobic performance (Vo2 peak, endurance cycling) was not impacted by CR, but arm flexion endurance decreased by 20%. In conclusion, 3 wk of caloric restriction reduced leucine flux and R(ox) during exercise in normal-weight young men. However, despite negative nitrogen balance and loss of lean mass, whole body exercise performance was well maintained in response to CR.
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Affiliation(s)
- Anne L Friedlander
- Geriatric Research Education and Clinical Center and Research and Medical Services, Veterans Affairs Palo Alto Health Care System, Palo Alto, CA 94304, USA.
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Abstract
In the recovery period after exercise there is an increase in oxygen uptake termed the 'excess post-exercise oxygen consumption' (EPOC), consisting of a rapid and a prolonged component. While some studies have shown that EPOC may last for several hours after exercise, others have concluded that EPOC is transient and minimal. The conflicting results may be resolved if differences in exercise intensity and duration are considered, since this may affect the metabolic processes underlying EPOC. Accordingly, the absence of a sustained EPOC after exercise seems to be a consistent finding in studies with low exercise intensity and/or duration. The magnitude of EPOC after aerobic exercise clearly depends on both the duration and intensity of exercise. A curvilinear relationship between the magnitude of EPOC and the intensity of the exercise bout has been found, whereas the relationship between exercise duration and EPOC magnitude appears to be more linear, especially at higher intensities. Differences in exercise mode may potentially contribute to the discrepant findings of EPOC magnitude and duration. Studies with sufficient exercise challenges are needed to determine whether various aerobic exercise modes affect EPOC differently. The relationships between the intensity and duration of resistance exercise and the magnitude and duration of EPOC have not been determined, but a more prolonged and substantial EPOC has been found after hard- versus moderate-resistance exercise. Thus, the intensity of resistance exercise seems to be of importance for EPOC. Lastly, training status and sex may also potentially influence EPOC magnitude, but this may be problematic to determine. Still, it appears that trained individuals have a more rapid return of post-exercise metabolism to resting levels after exercising at either the same relative or absolute work rate; however, studies after more strenuous exercise bouts are needed. It is not determined if there is a sex effect on EPOC. Finally, while some of the mechanisms underlying the more rapid EPOC are well known (replenishment of oxygen stores, adenosine triphosphate/creatine phosphate resynthesis, lactate removal, and increased body temperature, circulation and ventilation), less is known about the mechanisms underlying the prolonged EPOC component. A sustained increased circulation, ventilation and body temperature may contribute, but the cost of this is low. An increased rate of triglyceride/fatty acid cycling and a shift from carbohydrate to fat as substrate source are of importance for the prolonged EPOC component after exhaustive aerobic exercise. Little is known about the mechanisms underlying EPOC after resistance exercise.
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32
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Stein TP, Donaldson MR, Leskiw MJ, Schluter MD, Baggett DW, Boden G. Branched-chain amino acid supplementation during bed rest: effect on recovery. J Appl Physiol (1985) 2003; 94:1345-52. [PMID: 12471043 DOI: 10.1152/japplphysiol.00481.2002] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Bed rest is associated with a loss of protein from the weight-bearing muscle. The objectives of this study are to determine whether increasing dietary branched-chain amino acids (BCAAs) during bed rest improves the anabolic response after bed rest. The study consisted of a 1-day ambulatory period, 14 days of bed rest, and a 4-day recovery period. During bed rest, dietary intake was supplemented with either 30 mmol/day each of glycine, serine, and alanine (group 1) or with 30 mmol/day each of the three BCAAs (group 2). Whole body protein synthesis was determined with U-(15)N-labeled amino acids, muscle, and selected plasma protein synthesis with l-[(2)H(5)]phenylalanine. Total glucose production and gluconeogenesis from alanine were determined with l-[U-(13)C(3)]alanine and [6,6-(2)H(2)]glucose. During bed rest, nitrogen (N) retention was greater with BCAA feeding (56 +/- 6 vs. 26 +/- 12 mg N. kg(-1). day(-1), P < 0.05). There was no effect of BCAA supplementation on either whole body, muscle, or plasma protein synthesis or the rate of 3-MeH excretion. Muscle tissue free amino acid concentrations were increased during bed rest with BCAA (0.214 +/- 0.066 vs. 0.088 +/- 0.12 nmol/mg protein, P < 0.05). Total glucose production and gluconeogenesis from alanine were unchanged with bed rest but were significantly reduced (P < 0.05) with the BCAA group in the recovery phase. In conclusion, the improved N retention during bed rest is due, at least in part, to accretion of amino acids in the tissue free amino acid pools. The amount accreted is not enough to impact protein kinetics in the recovery phase but does improve N retention by providing additional essential amino acids in the early recovery phase.
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Affiliation(s)
- T P Stein
- Department of Surgery, School of Osteopathic Medicine, University of Medicine and Dentistry of New Jersey, Stratford, New Jersey 08084, USA.
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Cortes CW, Thompson PD, Moyna NM, Schluter MD, Leskiw MJ, Donaldson MR, Duncan BH, Stein TP. Protein kinetics in stable heart failure patients. J Appl Physiol (1985) 2003; 94:295-300. [PMID: 12391030 DOI: 10.1152/japplphysiol.00654.2001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Heart failure (HF) is a slow progressive syndrome characterized by low cardiac output and peripheral metabolic, biochemical, and histological alterations. Protein loss and reduced protein turnover occur with aging, but the consequences of congestive HF (CHF) superimposed on the normal aging response are unknown. This study has two objectives: 1) to determine whether there was a difference between older age-matched controls and those with stable HF (i.e., ischemic pathology) in whole body protein turnover and 2) to determine whether protein metabolism in liver and skeletal muscle protein turnover is impacted by CHF. We measured the whole body protein synthesis rate with a U-(15)N-labeled algal protein hydrolysate in 10 patients with CHF and in 10 age-matched controls. Muscle fractional synthesis rate of lateral vastus muscle was determined with [U-(13)C]alanine on muscle biopsies obtained by a standard percutaneous needle biopsy technique. Fractional synthesis rates of five plasma proteins of hepatic origin (fibrinogen, complement C-3, ceruloplasmin, transferrin, and very low-density lipoprotein apoliprotein B-100) were determined by using (2)H(5)-labeled l-phenylalanine as tracer. Results showed that whole body protein synthesis rate was reduced in CHF patients (3.09 +/- 0.19 vs. 2.25 +/- 0.71 g protein x kg(-1) x day(-1), P < 0.05) as was muscle fractional synthesis rate (3.02 +/- 0.58 vs. 1.33 +/- 0.71%/day, P < 0.05) and very low-density lipoprotein apoliprotein B-100 (265 +/- 25 vs. 197 +/- 16%/day, P < 0.05). CHF patients were hyperinsulinemic (9.6 +/- 3.1 vs. 47.0 +/- 7.8 microU/ml, P < 0.01). The results were compared with those found with bed rest patients. In conclusion, protein turnover is depressed in CHF patients, and both skeletal muscle and liver are impacted. These results are similar to those found with bed rest, which suggests that inactivity is a factor in depressed protein metabolism.
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Affiliation(s)
- Charles W Cortes
- Division of Preventive Cardiology, Hartford Hospital, Connecticut 06102, USA.
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Mazzaferro EM, Hackett TB, Stein TP, Ogilvie GK, Wingfield WE, Walton J, Turner AS, Fettman MJ. Metabolic alterations in dogs with osteosarcoma. Am J Vet Res 2001; 62:1234-9. [PMID: 11497444 DOI: 10.2460/ajvr.2001.62.1234] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate changes in resting energy expenditure (REE) as well as protein and carbohydrate metabolism in dogs with osteosarcoma (OSA). ANIMALS 15 weight-stable dogs with OSA that did not have other concurrent metabolic or endocrine illness and twelve 1-year-old sexually intact female Beagles (control dogs). PROCEDURES Indirect calorimetry was performed on all dogs to determine REE and respiratory quotient (RQ). Stable isotope tracers (15N-glycine, 4.5 mg/kg of body weight, IV; 6,6-deuterium-glucose, 4.5 mg/kg, IV as a bolus, followed by continuous-rate infusion at 1.5 mg/kg/h for 3 hours) were used to determine rate of protein synthesis and glucose flux in all dogs. Dual-energy x-ray absorptiometry (DEXA) scans were performed to determine total body composition. RESULTS Accounting for metabolic body size, REE in dogs with OSA was significantly higher before and after surgery, compared with REE of healthy control dogs. The RQ values did not differ significantly between groups. Dogs with OSA also had decreased rates of protein synthesis, increased urinary nitrogen loss, and increased glucose flux during the postoperative period. CONCLUSIONS AND CLINICAL RELEVANCE Alterations in energy expenditure, protein synthesis, urinary nitrogen loss, and carbohydrate flux were evident in dogs with OSA, similar to results documented in humans with neoplasia. Changes were documented in REE as well as protein and carbohydrate metabolism in dogs with OSA. These changes were evident even in dogs that did not have clinical signs of cachexia.
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Affiliation(s)
- E M Mazzaferro
- Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523, USA
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Abstract
Energy restriction (ER), without malnutrition, increases maximum life span and retards the development of a broad array of pathophysiological changes in laboratory rodents. The mechanism responsible for the retardation of aging by ER is, however, unknown. One proposed explanation is a reduction in energy expenditure (EE). Reduced EE may increase life span by decreasing the number of oxygen molecules interacting with mitochondria, thereby lowering reactive oxygen species (ROS) production. As a step toward testing this hypothesis, it is important to determine the effect of ER on EE. Several whole-body, organ, and cellular studies have measured the influence of ER on EE. In general, whole-body studies have reported an acute decrease in mass-adjusted EE that disappears with long-term ER. Organ-specific studies have shown that decreases in EE of liver and gastrointestinal tract are primarily responsible for initial reductions in EE with ER. These data, however, do not determine whether cellular EE is altered with ER. Three major processes contributing to resting EE at the cellular level are mitochondrial proton leak, Na(+)-K(+)-ATPase activity, and protein turnover. Studies suggest that proton leak and Na(+)-K(+)-ATPase activity are decreased with ER, whereas protein turnover is either unchanged or slightly increased with ER. Thus, two of the three major processes contributing to resting EE at the cellular level may be decreased with ER. Although additional cellular measurements are needed, the current results suggest that a lowering of EE could be a mechanism for the action of ER.
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Affiliation(s)
- J J Ramsey
- Wisconsin Regional Primate Research Center, Madison, WI 53715-1299, USA.
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Rochon C, Tauveron I, Dejax C, Benoit P, Capitan P, Bayle G, Prugnaud J, Fabricio A, Berry C, Champredon C, Thieblot P, Grizard J. Response of leucine metabolism to hyperinsulinemia in hypothyroid patients before and after thyroxine replacement. J Clin Endocrinol Metab 2000; 85:697-706. [PMID: 10690879 DOI: 10.1210/jcem.85.2.6380] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We have investigated the effect of hypothyroidism and insulin on protein metabolism in humans. Six hypothyroid patients were studied in a postabsorptive state before and after 5 months of regular treatment for hypothyroidism (153 +/- 17 microg/day of L-T4). The effect of insulin was assessed under hyperinsulinemic euglycemic and eukalemic conditions. Insulin was infused for 140 min at 0.0063 +/- 0.0002 nmol/kg x min. An amino acid infusion was used to blunt insulin-induced hypoaminoacidemia. Whole body protein turnover was measured using L-[1-13C] leucine. When compared to L-T4-induced subclinical thyrotoxic state, hypothyroidism induced a significant decrease (P < 0.05) in leucine endogenous appearance rate (a reflection of proteolysis; 0.89 +/- 0.09 vs. 1.33 +/- 0.05 micromol/kg x min), oxidation (0.19 +/- 0.02 vs. 0.25 +/- 0.03 micromol/kg x min), and nonoxidative disposal (a reflection of protein synthesis; 0.87 +/- 0.11 vs. 1.30 +/- 0.05 micromol/ kg x min). Insulin lowered proteolysis during both the subclinical thyrotoxic and hypothyroid states. Hypothyroidism impaired the antiproteolytic effects of insulin. Thyroid hormones are, therefore, essential for the normal antiproteolytic action of insulin.
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Affiliation(s)
- C Rochon
- Centre de Recherche en Nutrition Humaine d'Auvergne: Unité d'Etude du Métabolisme Azoté, Institut National de la Recherche Agronomique, Champanelle, France
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Stein TP, Leskiw MJ, Schluter MD, Donaldson MR, Larina I. Protein kinetics during and after long-duration spaceflight on MIR. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 276:E1014-21. [PMID: 10362613 DOI: 10.1152/ajpendo.1999.276.6.e1014] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Human spaceflight is associated with a loss of body protein. Bed rest studies suggest that the reduction in the whole body protein synthesis (PS) rate should be approximately 15%. The objectives of this experiment were to test two hypotheses on astronauts and cosmonauts during long-duration (>3 mo) flights on MIR: that 1) the whole body PS rate will be reduced and 2) dietary intake and the PS rate should be increased postflight because protein accretion is occurring. The 15N glycine method was used for measuring whole body PS rate before, during, and after long-duration spaceflight on the Russian space station MIR. Dietary intake was measured together with the protein kinetics. Results show that subjects lost weight during flight (4.64 +/- 1.0 kg, P < 0.05). Energy intake was decreased inflight (2,854 +/- 268 vs. 2,145 +/- 190 kcal/day, n = 6, P < 0.05), as was the PS rate (226 +/- 24 vs. 97 +/- 11 g protein/day, n = 6, P < 0.01). The reduction in PS correlated with the reduction in energy intake (r2 = 0.86, P < 0.01, n = 6). Postflight energy intake and PS returned to, but were not increased over, the preflight levels. We conclude that the reduction in PS found was greater than predicted from ground-based bed rest experiments because of the shortfall in dietary intake. The expected postflight anabolic state with increases in dietary intake and PS did not occur during the first 2 wk after landing.
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Affiliation(s)
- T P Stein
- Department of Surgery, School of Osteopathic Medicine, University of Medicine and Dentistry of New Jersey, Stratford, New Jersey 08084, USA.
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Stein TP, Leskiw MJ, Schluter MD, Hoyt RW, Lane HW, Gretebeck RE, LeBlanc AD. Energy expenditure and balance during spaceflight on the space shuttle. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 276:R1739-48. [PMID: 10362755 DOI: 10.1152/ajpregu.1999.276.6.r1739] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The objectives of this study were as follows: 1) to measure human energy expenditure (EE) during spaceflight on a shuttle mission by using the doubly labeled water (DLW) method; 2) to determine whether the astronauts were in negative energy balance during spaceflight; 3) to use the comparison of change in body fat as measured by the intake DLW EE, 18O dilution, and dual energy X-ray absorptiometry (DEXA) to validate the DLW method for spaceflight; and 4) to compare EE during spaceflight against that found with bed rest. Two experiments were conducted: a flight experiment (n = 4) on the 16-day 1996 life and microgravity sciences shuttle mission and a 6 degrees head-down tilt bed rest study with controlled dietary intake (n = 8). The bed rest study was designed to simulate the flight experiment and included exercise. Two EE determinations were done before flight (bed rest), during flight (bed rest), and after flight (recovery). Energy intake and N balance were monitored for the entire period. Results were that body weight, water, fat, and energy balance were unchanged with bed rest. For the flight experiment, decreases in weight (2.6 +/- 0.4 kg, P < 0.05) and N retention (-2. 37 +/- 0.45 g N/day, P < 0.05) were found. Dietary intake for the four astronauts was reduced in flight (3,025 +/- 180 vs. 1,943 +/- 179 kcal/day, P < 0.05). EE in flight was 3,320 +/- 155 kcal/day, resulting in a negative energy balance of 1,355 +/- 80 kcal/day (-15. 7 +/- 1.0 kcal. kg-1. day-1, P < 0.05). This corresponded to a loss of 2.1 +/- 0.4 kg body fat, which was within experimental error of the fat loss determined by 18O dilution (-1.4 +/- 0.5 kg) and DEXA (-2.4 +/- 0.4 kg). All three methods showed no change in body fat with bed rest. In conclusion, 1) the DLW method for measuring EE during spaceflight is valid, 2) the astronauts were in severe negative energy balance and oxidized body fat, and 3) in-flight energy (E) requirements can be predicted from the equation: E = 1.40 x resting metabolic rate + exercise.
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Affiliation(s)
- T P Stein
- Department of Surgery, University of Medicine and Dentistry of New Jersey, School of Osteopathic Medicine, Stratford, New Jersey 08084, USA.
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Ebbeling CB, Rodriguez NR. Effects of exercise combined with diet therapy on protein utilization in obese children. Med Sci Sports Exerc 1999; 31:378-85. [PMID: 10188741 DOI: 10.1097/00005768-199903000-00005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Hypocaloric therapy may adversely affect protein utilization in obese children given that metabolic reactions involving protein, a nutrient essential for growth, are energy-dependent. Because physical activity influences nutrient utilization and may modulate the effects of reduced energy intake, exercise combined with diet therapy may be beneficial with regard to protein metabolism. The primary purpose of this study was to evaluate changes in protein utilization in response to sequential addition of an exercise program to dietary intervention in obese children. METHODS After a 2-wk baseline period, five subjects aged 8-10 yr reduced energy intake [-2092 to -2510 kJ.d(-1)(-500 to -600 kcal.d(-1))] for 12 wk. A walking program [5 d.wk(-1), 3.2-4.8 km.d(-1) (2-3 miles.d(-1))] was implemented during the final 6 wk of diet therapy. At baseline and after phases I (diet only) and II (exercise and diet) of intervention, 15N-glycine was used to assess protein synthesis (PS), protein breakdown (PB), net turnover (NET = PS - PB), and nitrogen flux (Q). RESULTS Subjects lost 4.2+/-0.4 kg during the 12-wk intervention period (P < or = 0.05). With diet only, NET decreased (P < or = 0.05) due to a reduction in PS (P < or = 0.05) accompanied by no change in PB. Although PS increased with walking (P < or = 0.05), NET did not return to baseline levels due to a concurrent increase in PB (P < or = 0.05). Changes in PS and PB yielded an increase in Q (P < or = 0.05), a measure of amino acid cycling between protein and free amino acid pools. CONCLUSIONS These results suggest that exercise offers metabolic benefits for obese children during diet-induced weight loss. Longitudinal studies are needed to assess long-term health outcomes associated with the observed changes in protein utilization.
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Affiliation(s)
- C B Ebbeling
- Department of Nutritional Sciences, University of Connecticut, Storrs 06269-4017, USA
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Abstract
Dietary treatment of pediatric obesity is a challenge given the need for adequate nutrients to support the maintenance of lean tissue and growth. The primary purpose of this investigation was to assess the effects of reduced energy intake on protein turnover in obese children aged 8 to 10 years. Following a 2-week baseline period, 16 subjects reduced energy intake during a 6-week intervention period. At baseline and following the intervention, 15N-glycine methodology was used to measure nitrogen flux (Q), protein synthesis (PS), protein breakdown (PB), and net turnover ([NET] PS - PB). Other criterion measures included resting metabolic rate (RMR), fat mass (FM), fat-free mass (FFM), urinary creatinine to height ratio (Cr:Ht), and nitrogen balance (NB). On average, subjects lost 2.2 +/- 0.3 kg, of which greater than 85% was FM. Decreased Q (P = .03) indicated downregulation of protein turnover in response to diet-induced weight loss. While PB did not change, NET declined slightly (P = .06) as a consequence of reduced PS (P = .03). Reductions in FFM (P = .09), Cr:Ht (P = .02), and NB (P = .03) accompanied alterations in protein turnover, but there was no change in the RMR. In conclusion, while short-term therapy promoted the loss of FM and did not compromise RMR, practitioners must be cautious when prescribing diets, given the observed changes in protein utilization and somatic protein status. Longitudinal studies are needed to further characterize the metabolic responses of obese children to long-term diet therapy.
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Affiliation(s)
- C B Ebbeling
- Department of Nutritional Sciences, University of Connecticut, Storrs 06269-4017, USA
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Ferrando AA, Lane HW, Stuart CA, Davis-Street J, Wolfe RR. Prolonged bed rest decreases skeletal muscle and whole body protein synthesis. THE AMERICAN JOURNAL OF PHYSIOLOGY 1996; 270:E627-33. [PMID: 8928769 DOI: 10.1152/ajpendo.1996.270.4.e627] [Citation(s) in RCA: 219] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We sought to determine the extent to which the loss of lean body mass and nitrogen during inactivity was due to alterations in skeletal muscle protein metabolism. Six male subjects were studied during 7 days of diet stabilization and after 14 days of stimulated microgravity (-6 degrees bed rest). Nitrogen balance became more negative (P < 0.03) during the 2nd wk of bed rest. Leg and whole body lean mass decreased after bed rest (P < 0.05). Serum cortisol, insulin, insulin-like growth factor I, and testosterone values did not change. Arteriovenous model calculations based on the infusion of L-[ring-13C6]-phenylalanine in five subjects revealed a 50% decrease in muscle protein synthesis (PS; P < 0.03). Fractional PS by tracer incorporation into muscle protein also decreased by 46% (P < 0.05). The decrease in PS was related to a corresponding decrease in the sum of intracellular amino acid appearance from protein breakdown and inward transport. Whole body protein synthesis determined by [15N]alanine ingestion on six subjects also revealed a 14% decrease (P < 0.01). Neither model-derived nor whole body values for protein breakdown change significantly. These results indicate that the loss of body protein with inactivity is predominantly due to a decrease in muscle PS and that this decrease is reflected in both whole body and skeletal muscle measures.
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Affiliation(s)
- A A Ferrando
- National Aeronautics and Space Administration, Johnson Space Center, Houston 77058, USA
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Abstract
The quantitative contribution of hepatic glucose cycling to basal and glucagon-stimulated thermogenesis was investigated in seven normal healthy volunteers in whom energy expenditure (EE) was measured simultaneously with indirect calorimetry. Primed-constant infusions of 2-(2H1)-glucose and 6-6'-(2H2)-glucose were used to calculate hepatic glucose cycling. Gas chromatography/mass spectrometry was used to measure the plasma enrichment of isotopes. In response to hyperglucagonemia, basal EE increased an average of 7.1% +/- 2.3% (P < .05). This thermogenic effect of glucagon was completely blunted when insulin levels were increased sevenfold over the basal concentration. Hepatic glucose cycling comprised 15% +/- 4% of basal glucose turnover and increased more than 100% in response to isolated hyperglucagonemia. The increase in liver glucose cycling was observed also when serum insulin concentrations were increased sevenfold above baseline. Thus, we were able to induce dissociation of the activation of hepatic glucose cycling and the thermogenic response induced by hyperglucagonemia. From the quantitative point of view, the thermogenic cost of the cycles was less than 1% in both the basal and stimulated state. Thus, we concluded that hepatic glucose cycles play a quantitatively minor role in EE in man.
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Abstract
The mechanism governing short-term adaptation to dietary protein restriction was investigated in nine normal adults by measuring their metabolic response to a standard mixed meal, first while they were adapted to a conventional, high-protein diet (day 1) and then again after they had eaten two low-protein meals (day 2). Urea appearance (measured as the sum of its urinary excretion and the change in body urea pool size), body retention of 15N-alanine included in each test meal, and whole-body protein turnover were calculated over the 9 hours following meal consumption on each day. Postprandial urea nitrogen appearance was 5.05 +/- 0.26 g/9 h on day 1 and decreased to 4.16 +/- 0.31 on day 2 (P < .05). Whole-body N flux (Q), protein synthesis (S), and protein breakdown (B) all decreased significantly on day 2 as assessed using either urea or ammonium end-product enrichments; however, recovery of 15N in the test meal as 15N-urea was similar on both days, approximately 22%. It is concluded that short-term metabolic adaptation occurs within two meals of reduced protein intake. The mechanism appears not to involve selectively an increased "first-pass" retention of dietary amino acids, but rather a general reduction in fed-state whole-body protein breakdown.
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Affiliation(s)
- A Taveroff
- McGill Nutrition and Food Science Centre, McGill University, Montreal, Quebec, Canada
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Stein TP, Leskiw MJ, Schluter MD. Effect of spaceflight on human protein metabolism. THE AMERICAN JOURNAL OF PHYSIOLOGY 1993; 264:E824-8. [PMID: 8498504 DOI: 10.1152/ajpendo.1993.264.5.e824] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Nitrogen balance and the whole body protein synthesis rate were measured before, during, and after a 9.5-day spaceflight mission on the space shuttle Columbia. Protein synthesis was measured by the single-pulse [15N]glycine method. Determinations were made 56, 26, and 18 days preflight, on flight days 2 and 8, and on days 0, 6, 14, and 45 postflight. We conclude that nitrogen balance was decreased during spaceflight. The decrease in nitrogen balance was greatest on the 1st day when food intake was reduced and again toward the end of the mission. An approximately 30% increase in protein synthesis above the preflight baseline was found for flight day 8 for all 6 subjects (P < 0.05), indicating that the astronauts showed a stress response to spaceflight.
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Affiliation(s)
- T P Stein
- Department of Surgery, University of Medicine and Dentistry of New Jersey, School of Osteopathic Medicine, Camden 08103
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