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Coppola S, Carucci L, Oglio F, Di Sarra C, Ozen G, Berni Canani R. Nutritional Strategies for the Prevention and Management of Cow's Milk Allergy in the Pediatric Age. Nutrients 2023; 15:3328. [PMID: 37571266 PMCID: PMC10421120 DOI: 10.3390/nu15153328] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 07/22/2023] [Accepted: 07/23/2023] [Indexed: 08/13/2023] Open
Abstract
Cow's milk allergy (CMA) is one of the most common pediatric food allergies. The prevalence and severity of CMA have increased dramatically in the last decades, under the pressure of environmental factors in genetically predisposed individuals. Among the environmental influences, nutritional factors play a crucial role. Diet is the most modifiable factor, representing a potential target for the prevention and treatment of CMA. In this review, we report the most scientific-based nutritional strategies for preventing and managing pediatric CMA. In addition, we propose the most complete supplement of compounds able to prevent nutrient deficiencies in CMA pediatric patients and to positively influence the disease course.
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Affiliation(s)
- Serena Coppola
- Department of Translational Medical Science, University of Naples Federico II, 80131 Naples, Italy; (S.C.); (L.C.); (F.O.); (C.D.S.); (G.O.)
- Immunonutrition Lab at the CEINGE Advanced Biotechnologies Research Center, University of Naples Federico II, 80131 Naples, Italy
| | - Laura Carucci
- Department of Translational Medical Science, University of Naples Federico II, 80131 Naples, Italy; (S.C.); (L.C.); (F.O.); (C.D.S.); (G.O.)
- Immunonutrition Lab at the CEINGE Advanced Biotechnologies Research Center, University of Naples Federico II, 80131 Naples, Italy
| | - Franca Oglio
- Department of Translational Medical Science, University of Naples Federico II, 80131 Naples, Italy; (S.C.); (L.C.); (F.O.); (C.D.S.); (G.O.)
- Immunonutrition Lab at the CEINGE Advanced Biotechnologies Research Center, University of Naples Federico II, 80131 Naples, Italy
| | - Claudia Di Sarra
- Department of Translational Medical Science, University of Naples Federico II, 80131 Naples, Italy; (S.C.); (L.C.); (F.O.); (C.D.S.); (G.O.)
- Immunonutrition Lab at the CEINGE Advanced Biotechnologies Research Center, University of Naples Federico II, 80131 Naples, Italy
| | - Gulsum Ozen
- Department of Translational Medical Science, University of Naples Federico II, 80131 Naples, Italy; (S.C.); (L.C.); (F.O.); (C.D.S.); (G.O.)
| | - Roberto Berni Canani
- Department of Translational Medical Science, University of Naples Federico II, 80131 Naples, Italy; (S.C.); (L.C.); (F.O.); (C.D.S.); (G.O.)
- Immunonutrition Lab at the CEINGE Advanced Biotechnologies Research Center, University of Naples Federico II, 80131 Naples, Italy
- European Laboratory for the Investigation of Food-Induced Diseases, University of Naples Federico II, 80131 Naples, Italy
- Task Force for Microbiome Studies, University of Naples Federico II, 80131 Naples, Italy
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Jiang Y, Zeng Y, Lu R, Zhang Y, Long L, Zheng X, Luo X, Mai B. Application of amino acids nitrogen stable isotopic analysis in bioaccumulation studies of pollutants: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 879:163012. [PMID: 36965734 DOI: 10.1016/j.scitotenv.2023.163012] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 03/17/2023] [Accepted: 03/18/2023] [Indexed: 05/17/2023]
Abstract
Accurately quantifying trophic positions (TP) to describe food web structure is an important element in studying pollutant bioaccumulation. In recent years, compound-specific nitrogen isotopic analysis of amino acids (AAs-N-CSIA) has been progressively applied as a potentially reliable tool for quantifying TP, facilitating a better understanding of pollutant food web transfer. Therefore, this review provides an overview of the analytical procedures, applications, and limitations of AAs-N-CSIA in pollutant (halogenated organic pollutants (HOPs) and heavy metals) bioaccumulation studies. We first summarize studies on the analytical techniques of AAs-N-CSIA, including derivatization, instrumental analysis, and data processing methods. The N-pivaloyl-i-propyl-amino acid ester method is a more suitable AAs derivatization method for quantifying TP. The AAs-N-CSIA application in pollutant bioaccumulation studies (e.g., Hg, MeHg, and HOPs) is discussed, and its application in conjunction with various techniques (e.g., spatial analysis, food source analysis, and compound tracking techniques, etc.) to research the influence of pollutant levels on organisms is summarized. Finally, the limitations of AAs-N-CSIA in pollutant bioaccumulation studies are discussed, including the use of single empirical values of βglu/phe and TDFglu/phe that result in large errors in TP quantification. The weighted βglu/phe and the multi-TDFglu/phe models are still challenging to solve for accurate TP quantification of omnivores; however, factors affecting the variation of βglu/phe and TDFglu/phe are unclear, especially the effect of pollutant bioaccumulation in organisms on internal AA metabolic processes.
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Affiliation(s)
- Yiye Jiang
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yanhong Zeng
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China.
| | - Ruifeng Lu
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yanting Zhang
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ling Long
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaobo Zheng
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Provincial Key Laboratory of Agricultural & Rural Pollution Abatement and Environmental Safety, College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, China
| | - Xiaojun Luo
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China
| | - Bixian Mai
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China
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Millward DJ. Interactions between Growth of Muscle and Stature: Mechanisms Involved and Their Nutritional Sensitivity to Dietary Protein: The Protein-Stat Revisited. Nutrients 2021; 13:729. [PMID: 33668846 PMCID: PMC7996181 DOI: 10.3390/nu13030729] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 02/15/2021] [Accepted: 02/22/2021] [Indexed: 02/07/2023] Open
Abstract
Childhood growth and its sensitivity to dietary protein is reviewed within a Protein-Stat model of growth regulation. The coordination of growth of muscle and stature is a combination of genetic programming, and of two-way mechanical interactions involving the mechanotransduction of muscle growth through stretching by bone length growth, the core Protein-Stat feature, and the strengthening of bone through muscle contraction via the mechanostat. Thus, growth in bone length is the initiating event and this is always observed. Endocrine and cellular mechanisms of growth in stature are reviewed in terms of the growth hormone-insulin like growth factor-1 (GH-IGF-1) and thyroid axes and the sex hormones, which together mediate endochondral ossification in the growth plate and bone lengthening. Cellular mechanisms of muscle growth during development are then reviewed identifying (a) the difficulties posed by the need to maintain its ultrastructure during myofibre hypertrophy within the extracellular matrix and the concept of muscle as concentric "bags" allowing growth to be conceived as bag enlargement and filling, (b) the cellular and molecular mechanisms involved in the mechanotransduction of satellite and mesenchymal stromal cells, to enable both connective tissue remodelling and provision of new myonuclei to aid myofibre hypertrophy and (c) the implications of myofibre hypertrophy for protein turnover within the myonuclear domain. Experimental data from rodent and avian animal models illustrate likely changes in DNA domain size and protein turnover during developmental and stretch-induced muscle growth and between different muscle fibre types. Growth of muscle in male rats during adulthood suggests that "bag enlargement" is achieved mainly through the action of mesenchymal stromal cells. Current understanding of the nutritional regulation of protein deposition in muscle, deriving from experimental studies in animals and human adults, is reviewed, identifying regulation by amino acids, insulin and myofibre volume changes acting to increase both ribosomal capacity and efficiency of muscle protein synthesis via the mechanistic target of rapamycin complex 1 (mTORC1) and the phenomenon of a "bag-full" inhibitory signal has been identified in human skeletal muscle. The final section deals with the nutritional sensitivity of growth of muscle and stature to dietary protein in children. Growth in length/height as a function of dietary protein intake is described in the context of the breastfed child as the normative growth model, and the "Early Protein Hypothesis" linking high protein intakes in infancy to later adiposity. The extensive paediatric studies on serum IGF-1 and child growth are reviewed but their clinical relevance is of limited value for understanding growth regulation; a role in energy metabolism and homeostasis, acting with insulin to mediate adiposity, is probably more important. Information on the influence of dietary protein on muscle mass per se as opposed to lean body mass is limited but suggests that increased protein intake in children is unable to promote muscle growth in excess of that linked to genotypic growth in length/height. One possible exception is milk protein intake, which cohort and cross-cultural studies suggest can increase height and associated muscle growth, although such effects have yet to be demonstrated by randomised controlled trials.
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Affiliation(s)
- D Joe Millward
- Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK
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Kim BJ, Lee SH, Isales CM, Koh JM, Hamrick MW. The positive association of total protein intake with femoral neck strength (KNHANES IV). Osteoporos Int 2018; 29:1397-1405. [PMID: 29511792 PMCID: PMC6014874 DOI: 10.1007/s00198-018-4451-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 02/15/2018] [Indexed: 12/22/2022]
Abstract
UNLABELLED Data gathered from a nationally representative cohort demonstrate that higher dietary protein intake was positively associated with the composite indices of femoral neck strength in both men and women, suggesting that higher protein intake may contribute to lower risk of hip fracture through the improvement of bone strength. INTRODUCTION Despite the general belief that higher protein intake may be helpful for bone homeostasis, its impact on human bone health is still debated. Furthermore, the association of dietary protein intake with femoral neck (FN) strength, which can predict fracture risk independently of bone mineral density (BMD), has not been thoroughly studied. METHODS This is a population-based, cross-sectional study from Korea National Health and Nutrition Examination Surveys, including 592 men aged 50 years or older and 590 postmenopausal women. The composite indices of FN strength, such as the compression strength index (CSI), bending strength index (BSI), and impact strength index (ISI), were generated by combining BMD, body weight, and height with the femoral axis length and width, which were measured by dual-energy X-ray absorptiometry. RESULTS After adjustment for confounders, total protein intake (g/kg/day) positively correlated with all three FN composite indices in both genders (P = 0.006 to 0.035), except for BSI showing marginal significance in postmenopausal women (P = 0.093). Consistently, compared with subjects in lowest total protein intake quartile, those in the highest quartile showed markedly higher CSI, BSI, and ISI values (P = 0.043 to < 0.001), with a dose-response manner across increasing total protein intake quartile categories in both men and women (P for trend = 0.028 to < 0.001). CONCLUSIONS These findings provide the clinical evidence that higher dietary protein intake can play a beneficial role on bone health through the increase of FN strength relative to load in adults.
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Affiliation(s)
- B-J Kim
- Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Laney Walker Blvd. CB2915, Augusta, GA, 30912, USA
| | - S H Lee
- Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - C M Isales
- Departments of Orthopaedic Surgery, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - J-M Koh
- Division of Endocrinology and Metabolism, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - M W Hamrick
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Laney Walker Blvd. CB2915, Augusta, GA, 30912, USA.
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O'Connell TC. 'Trophic' and 'source' amino acids in trophic estimation: a likely metabolic explanation. Oecologia 2017; 184:317-326. [PMID: 28584941 PMCID: PMC5487837 DOI: 10.1007/s00442-017-3881-9] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 05/08/2017] [Indexed: 11/18/2022]
Abstract
Amino acid nitrogen isotopic analysis is a relatively new method for estimating trophic position. It uses the isotopic difference between an individual's 'trophic' and 'source' amino acids to determine its trophic position. So far, there is no accepted explanation for the mechanism by which the isotopic signals in 'trophic' and 'source' amino acids arise. Yet without a metabolic understanding, the utility of nitrogen isotopic analyses as a method for probing trophic relations, at either bulk tissue or amino acid level, is limited. I draw on isotopic tracer studies of protein metabolism, together with a consideration of amino acid metabolic pathways, to suggest that the 'trophic'/'source' groupings have a fundamental metabolic origin, to do with the cycling of amino-nitrogen between amino acids. 'Trophic' amino acids are those whose amino-nitrogens are interchangeable, part of a metabolic amino-nitrogen pool, and 'source' amino acids are those whose amino-nitrogens are not interchangeable with the metabolic pool. Nitrogen isotopic values of 'trophic' amino acids will reflect an averaged isotopic signal of all such dietary amino acids, offset by the integrated effect of isotopic fractionation from nitrogen cycling, and modulated by metabolic and physiological effects. Isotopic values of 'source' amino acids will be more closely linked to those of equivalent dietary amino acids, but also modulated by metabolism and physiology. The complexity of nitrogen cycling suggests that a single identifiable value for 'trophic discrimination factors' is unlikely to exist. Greater consideration of physiology and metabolism should help in better understanding observed patterns in nitrogen isotopic values.
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Affiliation(s)
- T C O'Connell
- Department of Archaeology and Anthropology, University of Cambridge, Downing Street, Cambridge, CB2 3DZ, UK.
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Nutrition, infection and stunting: the roles of deficiencies of individual nutrients and foods, and of inflammation, as determinants of reduced linear growth of children. Nutr Res Rev 2017; 30:50-72. [PMID: 28112064 DOI: 10.1017/s0954422416000238] [Citation(s) in RCA: 161] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The regulation of linear growth by nutritional and inflammatory influences is examined in terms of growth-plate endochondral ossification, in order to better understand stunted growth in children. Linear growth is controlled by complex genetic, physiological, and nutrient-sensitive endocrine/paracrine/autocrine mediated molecular signalling mechanisms, possibly including sleep adequacy through its influence on growth hormone secretion. Inflammation, which accompanies most infections and environmental enteric dysfunction, inhibits endochondral ossification through the action of mediators including proinflammatory cytokines, the activin A-follistatin system, glucocorticoids and fibroblast growth factor 21 (FGF21). In animal models linear growth is particularly sensitive to dietary protein as well as Zn intake, which act through insulin, insulin-like growth factor-1 (IGF-1) and its binding proteins, triiodothyronine, amino acids and Zn2+ to stimulate growth-plate protein and proteoglycan synthesis and cell cycle progression, actions which are blocked by corticosteroids and inflammatory cytokines. Observational human studies indicate stunting to be associated with nutritionally poor, mainly plant-based diets. Intervention studies provide some support for deficiencies of energy, protein, Zn and iodine and for multiple micronutrient deficiencies, at least during pregnancy. Of the animal-source foods, only milk has been specifically and repeatedly shown to exert an important influence on linear growth in both undernourished and well-nourished children. However, inflammation, caused by infections, environmental enteric dysfunction, which may be widespread in the absence of clean water, adequate sanitation and hygiene (WASH), and endogenous inflammation associated with excess adiposity, in each case contributes to stunting, and may explain why nutritional interventions are often unsuccessful. Current interventions to reduce stunting are targeting WASH as well as nutrition.
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Wu AM, Sun XL, Lv QB, Zhou Y, Xia DD, Xu HZ, Huang QS, Chi YL. The relationship between dietary protein consumption and risk of fracture: a subgroup and dose-response meta-analysis of prospective cohort studies. Sci Rep 2015; 5:9151. [PMID: 25779888 PMCID: PMC5376209 DOI: 10.1038/srep09151] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 02/12/2015] [Indexed: 12/31/2022] Open
Abstract
It is still debate of the relationship between the dietary protein consumption and risk of fracture. We searched Medline and Embase to assess the effects of dietary protein consumption on risk of fracture. Twelve prospective cohort studies with 407,104 participants were included, higher total protein consumption may be decrease 11% risk of hip fractures, with adj. RR of 0.89 (0.82, 0.97), no significant difference was found for total protein and risk of all fractures and limb fracture; for animal protein consumption and risk of all fractures and hip fracture, with adj.RR of 0.79 (032, 1.96) and 1.04 (0.70, 1.54); for vegetable protein consumption and risk of all fractures, hip fracture and limb fractures with adj.RR of 0.77 (0.52, 1.12), 1.00 (0.53, 1.91), and 0.94 (0.40, 2.22), the subgroup of vegetable protein consumption and risk of all fractures of postmenopausal women with adj.RR of 0.78(0.52,1.16). Dose-response meta-analysis the relationship of total/animal/vegetable protein and hip fracture was consistent to the results of forest plot, the line of total protein and hip fracture was below the Y = 1.0 line. This meta-analysis showed that total dietary protein consumption may be decrease the risk of hip fracture, but not for animal or vegetable protein.
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Affiliation(s)
- Ai-Min Wu
- Department of Orthopaedics, Second Affiliated Hospital of Wenzhou Medical University, 109# XueYuan Xi Road. 325027, Wenzhou, Zhejiang, China
| | - Xiao-Lei Sun
- Department of Orthopaedics, Tianjin hospital, 406 Jiefang Nan Road. 300211, Tianjin, China
| | - Qing-Bo Lv
- Department of Orthopaedics, Second Affiliated Hospital of Wenzhou Medical University, 109# XueYuan Xi Road. 325027, Wenzhou, Zhejiang, China
| | - Yong Zhou
- Department of Orthopaedics, Second Affiliated Hospital of Wenzhou Medical University, 109# XueYuan Xi Road. 325027, Wenzhou, Zhejiang, China
| | - Dong-Dong Xia
- Department of Orthopaedics, Shanghai East Hospital, Tongji University School of Medicine, 150 Jimo Road. 200120Pudong, Shanghai, China
| | - Hua-Zi Xu
- Department of Orthopaedics, Second Affiliated Hospital of Wenzhou Medical University, 109# XueYuan Xi Road. 325027, Wenzhou, Zhejiang, China
| | - Qi-Shan Huang
- Department of Orthopaedics, Second Affiliated Hospital of Wenzhou Medical University, 109# XueYuan Xi Road. 325027, Wenzhou, Zhejiang, China
| | - Yong-Long Chi
- Department of Orthopaedics, Second Affiliated Hospital of Wenzhou Medical University, 109# XueYuan Xi Road. 325027, Wenzhou, Zhejiang, China
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Millward DJ. Knowledge gained from studies of leucine consumption in animals and humans. J Nutr 2012; 142:2212S-2219S. [PMID: 23077184 DOI: 10.3945/jn.111.157370] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Leucine's wide-ranging metabolic influences have made it subject to special interest. It is abundant in the diet, especially in some milk and cereal proteins, in part due to its allocation of 6 codons in the genetic code, and individual dietary intakes range up to >250 mg · kg(-1) · d(-1). It influences many cell functions by various mechanisms, which include allosteric activation of enzymes, enabling ATP generation and insulin secretion from the pancreatic islet cell, and activation of signaling pathways. It is a mediator of the anabolic drive of dietary amino acids, stimulating anabolic hormone secretion and directly signaling protein deposition and growth through the stimulation of protein synthesis and restraint of proteolysis. Its signaling may involve the mammalian target of rapamycin complex and rapamycin-insensitive pathways responding to a leucine "transceptor," which combines leucine cellular transport, fueled by the intracellular-extracellular glutamine gradient, and a signaling response to changes in ionic and water balance and cell volume. In animal studies, dietary leucine supplementation has reversed many of the adverse influences of a high-fat diet, consistent with a benefit for healthy weight maintenance in humans for which evidence is accumulating. The implications for safety of leucine-supplemented diets are discussed in terms of adversely lowering valine and isoleucine concentrations and inducing hyperammonemia through overloading peripheral glutamine synthetic pathways. Finally, the apparently high human leucine requirement is explained in terms of both an adaptive metabolic demand model of requirements and the design and analysis of human studies, which may overestimate values.
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Affiliation(s)
- D Joe Millward
- Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford, Surrey, UK.
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Millward DJ. A protein-stat mechanism for regulation of growth and maintenance of the lean body mass. Nutr Res Rev 2012; 8:93-120. [PMID: 19094281 DOI: 10.1079/nrr19950008] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- D J Millward
- Centre for Nutrition and Food Safety, School of Biological Sciences, University of Surrey, Guildford GU2 5XH
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Grizard J, Dardevet D, Papet I, Mosoni L, Mirand PP, Attaix D, Tauveron I, Bonin D, Arnal M. Nutrient regulation of skeletal muscle protein metabolism in animals. The involvement of hormones and substrates. Nutr Res Rev 2012; 8:67-91. [PMID: 19094280 DOI: 10.1079/nrr19950007] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- J Grizard
- Laboratoire d'Etude du Métabolisme Azoté, Institut National de la Recherche Agronomique, Centre de Clermont-Ferrand - Theix, Centre de Recherche en Nutrition Humaine d'Auvergne, 63122 Saint-Genès-Champanelle, France
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Abstract
Dietary guidelines from a variety of sources are generally congruent that an adequate dietary protein intake for persons over the age of 19 is between 0·8–0·9 g protein/kg body weight/d. According to the US/Canadian Dietary Reference Intakes, the RDA for protein of 0·8 g protein/kg/d is “…the average daily intake level that is sufficient to meet the nutrient requirement of nearly all [~98 %]… healthy individuals…” The panel also states that “…no additional dietary protein is suggested for healthy adults undertaking resistance or endurance exercise.” These recommendations are in contrast to recommendations from the US and Canadian Dietetic Association: “Protein recommendations for endurance and strength trained athletes range from 1·2 to 1·7 g/kg/d.” The disparity between those setting dietary protein requirements and those who might be considered to be making practical recommendations for athletes is substantial. This may reflect a situation where an adaptive advantage of protein intakes higher than recommended protein requirements exists. That population protein requirements are still based on nitrogen balance may also be a point of contention since achieving balanced nitrogen intake and excretion likely means little to an athlete who has the primary goal of exercise performance. The goal of the present review is to critically analyse evidence from both acute and chronic dietary protein-based studies in which athletic performance, or correlates thereof, have been measured. An attempt will be made to distinguish between protein requirements set by data from nitrogen balance studies, and a potential adaptive ‘advantage’ for athletes of dietary protein in excess of the RDA.
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Plenary Lecture 3: Food and the planet: nutritional dilemmas of greenhouse gas emission reductions through reduced intakes of meat and dairy foods. Proc Nutr Soc 2009; 69:103-18. [PMID: 20003639 DOI: 10.1017/s0029665109991868] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Legally-binding legislation is now in place to ensure major reductions in greenhouse gas emissions in the UK. Reductions in intakes of meat and dairy products, which account for approximately 40% of food-related emissions, are an inevitable policy option. The present paper assesses, as far as is possible, the risk to nutritional status of such a policy in the context of the part played by these foods in overall health and well-being and their contribution to nutritional status for the major nutrients that they supply. Although meat may contribute to saturated fat intakes and a higher BMI, moderate meat consumption within generally-healthy population groups has no measurable influence on morbidity or mortality. However, high consumption of red and processed meat has been associated with increased risk of colo-rectal cancer and recent advice is to reduce intakes to a maximum of 70 g/d. Such reductions in meat and haem-Fe intake are unlikely to influence Fe status in functional terms. However, overall protein intakes would probably fall, with the potential for intakes to be less than current requirements for the elderly. Whether it is detrimental to health is uncertain and controversial. Zn intakes are also likely to fall, raising questions about child growth that are currently unanswerable. Milk and dairy products, currently specifically recommended for young children and pregnant women, provide 30-40% of dietary Ca, iodine, vitamin B12 and riboflavin. Population groups with low milk intakes generally show low intakes and poor status for each of these nutrients. Taken together it would appear that the reductions in meat and dairy foods, which are necessary to limit environmental damage, do pose serious nutritional challenges for some key nutrients. These challenges can be met, however, by improved public health advice on alternative dietary sources and by increasing food fortification.
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Darling AL, Millward DJ, Torgerson DJ, Hewitt CE, Lanham-New SA. Dietary protein and bone health: a systematic review and meta-analysis. Am J Clin Nutr 2009; 90:1674-92. [PMID: 19889822 DOI: 10.3945/ajcn.2009.27799] [Citation(s) in RCA: 183] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND There has been a resurgence of interest in the controversial relation between dietary protein and bone health. OBJECTIVE This article reports on the first systematic review and meta-analysis of the relation between protein and bone health in healthy human adults. DESIGN The MEDLINE (January 1966 to September 2007) and EMBASE (1974 to July 2008) databases were electronically searched for all relevant studies of healthy adults; studies of calcium excretion or calcium balance were excluded. RESULTS In cross-sectional surveys, all pooled r values for the relation between protein intake and bone mineral density (BMD) or bone mineral content at the main clinically relevant sites were significant and positive; protein intake explained 1-2% of BMD. A meta-analysis of randomized placebo-controlled trials indicated a significant positive influence of all protein supplementation on lumbar spine BMD but showed no association with relative risk of hip fractures. No significant effects were identified for soy protein or milk basic protein on lumbar spine BMD. CONCLUSIONS A small positive effect of protein supplementation on lumbar spine BMD in randomized placebo-controlled trials supports the positive association between protein intake and bone health found in cross-sectional surveys. However, these results were not supported by cohort study findings for hip fracture risk. Any effects found were small and had 95% CIs that were close to zero. Therefore, there is a small benefit of protein on bone health, but the benefit may not necessarily translate into reduced fracture risk in the long term.
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Affiliation(s)
- Andrea L Darling
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.
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Layman DK. Dietary Guidelines should reflect new understandings about adult protein needs. Nutr Metab (Lond) 2009; 6:12. [PMID: 19284668 PMCID: PMC2666737 DOI: 10.1186/1743-7075-6-12] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Accepted: 03/13/2009] [Indexed: 11/10/2022] Open
Abstract
Dietary Guidelines for Americans provide nutrition advice aimed at promoting healthy dietary choices for life-long health and reducing risk of chronic diseases. With the advancing age of the population, the 2010 Dietary Guidelines confront increasing risks for age-related problems of obesity, osteoporosis, type 2 diabetes, Metabolic Syndrome, heart disease, and sarcopenia. New research demonstrates that the meal distribution and amount of protein are important in maintaining body composition, bone health and glucose homeostasis. This editorial reviews the benefits of dietary protein for adult health, addresses omissions in current nutrition guidelines, and offers concepts for improving the Dietary Guidelines.
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Affiliation(s)
- Donald K Layman
- Department of Food Science & Human Nutrition, University of Illinois, Urbana, IL 61801, USA.
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Millward DJ, Layman DK, Tomé D, Schaafsma G. Protein quality assessment: impact of expanding understanding of protein and amino acid needs for optimal health. Am J Clin Nutr 2008; 87:1576S-1581S. [PMID: 18469291 DOI: 10.1093/ajcn/87.5.1576s] [Citation(s) in RCA: 205] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Protein quality describes characteristics of a protein in relation to its ability to achieve defined metabolic actions. Traditionally, this has been discussed solely in the context of a protein's ability to provide specific patterns of amino acids to satisfy the demands for synthesis of protein as measured by animal growth or, in humans, nitrogen balance. As understanding of protein's actions expands beyond its role in maintaining body protein mass, the concept of protein quality must expand to incorporate these newly emerging actions of protein into the protein quality concept. New research reveals increasingly complex roles for protein and amino acids in regulation of body composition and bone health, gastrointestinal function and bacterial flora, glucose homeostasis, cell signaling, and satiety. The evidence available to date suggests that quality is important not only at the minimum Recommended Dietary Allowance level but also at higher intakes. Currently accepted methods for measuring protein quality do not consider the diverse roles of indispensable amino acids beyond the first limiting amino acid for growth or nitrogen balance. As research continues to evolve in assessing protein's role in optimal health at higher intakes, there is also need to continue to explore implications for protein quality assessment.
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Affiliation(s)
- D Joe Millward
- School of Biomedical and Molecular Sciences, University of Surrey, Surrey, UK
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Muramatsu T. Nutrition and Whole-Body Protein Turnover in the Chicken in Relation to Mammalian Species. Nutr Res Rev 2007; 3:211-28. [DOI: 10.1079/nrr19900013] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Millward DJ, Jackson AA, Price G, Rivers JPW. Human Amino Acid and Protein Requirements: Current Dilemmas and Uncertainties. Nutr Res Rev 2007; 2:109-32. [DOI: 10.1079/nrr19890010] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Raina N, Jeejeebhoy KN. Effect of low-protein diet and protein supplementation on the expressions of TNF-alpha, TNFR-I, and TNFR-II in organs and muscle of LPS-injected rats. Am J Physiol Endocrinol Metab 2004; 286:E481-7. [PMID: 14625205 DOI: 10.1152/ajpendo.00355.2003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous studies had shown that increasing energy intake in anorexic TNF-alpha-treated rats increased morbidity due to stabilization of TNF activity by soluble and membrane TNF receptors (TNFR). Although protein supplementation reduces septic morbidity, its effect on TNF and TNFR is unknown. To determine the effect of low protein intake and supplementation on TNF and TNFR, 30 male Wistar rats weighing 250 g were fed a liquid defined-formula diet for 10 days and randomly allocated to 1) controls (C; n = 6), receiving normal energy and protein energy density of 0.047 MJ/60 ml + normal saline (NS); 2) low protein (LP; n = 6), receiving normal energy but a reduced protein-energy density of 0.012 MJ/60 ml + LPS; 3) refeeding (RF; n = 6), initially depleted on low-protein diet (10 days) and then repleted on normal protein (10 days) while receiving LPS; and 4) pair fed (P-F; n = 12), individual P-F rats being paired with individual LP or RF rats receiving NS. Protein and mRNA expression of TNF-alpha, TNFR-I, and TNFR-II in liver, spleen, and gastrocnemius were measured by Western blot and RT-PCR, respectively. In liver, the changes in TNF-alpha, TNFR-I, and TNFR-II were translational, whereas in spleen the effects were due to a combination of transcription and translation. In gastrocnemius, the effects were transcriptional/translational for TNFRs. In contrast, TNF-alpha mRNA was significantly increased, but TNF-alpha protein expression was reduced in LP rats compared with C and RF groups. In conclusion, protein deficiency in endotoxic rats increases the expression of TNFR-I and TNFR-II in all organs studied and TNF-alpha in selected ones. This increase is suppressed by refeeding protein. A differential pattern between translation and transcription of TNF-alpha and its receptors is present. Our data suggest that protein restriction may be deleterious in sepsis.
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MESH Headings
- Animals
- Antigens, CD/metabolism
- Diet, Protein-Restricted/methods
- Dietary Proteins/administration & dosage
- Dietary Proteins/metabolism
- Dietary Supplements
- Gene Expression Regulation/physiology
- Injections, Intramuscular
- Lipopolysaccharides/administration & dosage
- Liver/metabolism
- Male
- Muscle, Skeletal/metabolism
- Organ Specificity
- Rats
- Rats, Wistar
- Receptors, Tumor Necrosis Factor/metabolism
- Receptors, Tumor Necrosis Factor, Type I
- Receptors, Tumor Necrosis Factor, Type II
- Spleen/metabolism
- Tumor Necrosis Factor-alpha/metabolism
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Affiliation(s)
- Nilima Raina
- Department of Nutrition, University of Toronto, Toronto, Ontario, Canada M5S 1A8
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New SA, Millward DJ. Calcium, protein, and fruit and vegetables as dietary determinants of bone health. Am J Clin Nutr 2003; 77:1340-1; author reply 1341. [PMID: 12716695 DOI: 10.1093/ajcn/77.5.1340] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Tessari P, Kiwanuka E, Zanetti M, Barazzoni R. Postprandial body protein synthesis and amino acid catabolism measured with leucine and phenylalanine-tyrosine tracers. Am J Physiol Endocrinol Metab 2003; 284:E1037-42. [PMID: 12676651 DOI: 10.1152/ajpendo.00416.2002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Whether phenylalanine-tyrosine (Phe-Tyr) tracers yield estimates of postprandial protein synthesis comparable to those of the widely used leucine (Leu) tracer is unclear. We measured Leu oxidation (Ox), Phe hydroxylation (Hy), and their disposal into whole body protein synthesis before and after the administration of a mixed meal (62 kJ/kg body wt, 22% of energy as protein), over 4 h in healthy subjects. Both plasma and intracellular precursor pools were used. The amino acid data were extrapolated to body protein by assuming a fixed ratio of Leu to Phe in the proteins. In the postabsorptive state, whole body protein synthesis (expressed as mg. kg(-1). min(-1)) was similar between Leu and Phe-Tyr tracers irrespective of the precursor pool used. After the meal, Leu Ox, Phe Hy, and body protein synthesis increased (P < or = 0.01 vs. basal). With the use of intracellular precursor pools, the increase of protein synthesis with Phe-Tyr (+0.51 +/-0.21 mg. kg(-1). min(-1)) and Leu tracers (+0.57 +/- 0.14) were similar (P = not significant). In contrast, with plasma pools the increase of protein synthesis was more than twofold greater with Phe-Tyr (+1.17 +/- 0.19 mg. kg(-1). min(-1)) than that with Leu (0.50 +/- 0.13 mg. kg(-1). min(-1), P < 0.01). Direct correlations were found between Leu and Ox [using both plasma and intracellular pools (r < or = 0.65, P < or = 0.01)] but not between Phe and either plasma or intracellular Hy. In conclusion, 1) Phe-Tyr and Leu tracers yield comparable estimates of body protein synthesis postprandially, provided that intracellular precursor pools are used; 2) both Leu Ox and Phe Hy are stimulated by a mixed meal; 3) Phe does not correlate with Hy, which might be better related to the (unknown) portal Phe.
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Affiliation(s)
- Paolo Tessari
- Department of Clinical and Experimental Medicine, University of Padua, via Giustiniani 2, 35128 Padua, Italy.
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Abstract
For protein, progress is slow in defining quantifiable indicators of adequacy other than balance and growth. As far as current requirements are concerned, only in the case of infants and children is there any case for revision, and this change is to lower values. Such intakes would appear to be safe when consumed as milk formula. In pregnancy, notwithstanding the concern that deficiency may influence programming of disease in later life, there is little evidence of any increased need, and some evidence that increased intakes would pose a risk. For the elderly there is no evidence of an increased requirement or of benefit from increased intakes, except possibly for bone health. For adults, while we now know much more about metabolic adaptation to varying intakes, there would appear to be no case for a change in current recommendations. As far as risks and benefits of high intakes are concerned, there is now only a weak case for risk for renal function. For bone health the established views of risk of high protein intakes are not supported by newly-emerging data, with benefit indicated in the elderly. There is also circumstantial evidence for benefit on blood pressure and stroke mortality. With athletes there is little evidence of benefit of increased intakes in terms of performance, with older literature suggesting an adverse influence. Thus, given that a safe upper limit is currently defined as twice the reference nutrient intake, and that for individuals with high energy requirements this value (1.5 g/kg per d) is easily exceeded, there is a case for revising the definition of a safe upper limit.
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Affiliation(s)
- D J Millward
- Centre for Nutrition and Food Safety, School of Biological Sciences, University of Surrey, Guildford, UK.
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Millward DJ. Metabolic demands for amino acids and the human dietary requirement: Millward and rRvers (1988) revisited. J Nutr 1998; 128:2563S-2576S. [PMID: 9868206 DOI: 10.1093/jn/128.12.2563s] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In 1988, Millward and Rivers reappraised existing metabolic models for amino acid requirements. The metabolic demand for amino acids was reviewed in relation to both obligatory metabolic consumption and adaptive pathways of amino acid oxidation. The obligatory demand pattern was deemed unknowable from first principles except that the level of one amino acid would be similar to its concentration in an amount of tissue protein equivalent to the obligatory nitrogen loss. The adaptive demand pattern was predicted to vary in relation to the amount and the periodicity of food protein intake that influenced the amplitude of the diurnal cycle of gains and losses. A regulatory influence of protein intake on anabolism, the anabolic drive, was identified in animal studies; benefit appeared to derive from intakes in excess of the minimum for balance, which could facilitate definition of an optimal requirement. The inherent and design-related limitations of both nitrogen and stable isotope balance studies of requirement were recognized as a major problem in identifying secure values for indispensable amino acid requirements. A decade of research of increasing methodological sophistication has generated much new information, confirming the adaptive diurnal model of balance regulation and allowing development of the anabolic drive into a general protein-stat theory for coordinated control of growth and maintenance of the lean body mass. However, notwithstanding several new estimates of amino acid requirement values, definition of a widely accepted human amino acid requirement pattern remains unresolved. Although a case can be made for an adjusted 1985 FAO adult requirement pattern being a reasonable estimate of the obligatory indispensable amino acid requirements for human maintenance, the problems posed by adaptation, methodological inadequacies and lack of independent measures of adequacy mean that assessment of the adequacy of the human diet to satisfy amino acid needs remains inherently difficult.
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Affiliation(s)
- D J Millward
- Centre for Nutrition and Food Safety, School of Biological Sciences, University of Surrey, Guildford, Surrey GU2 5XH, UK
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Millward DJ, Fereday A, Gibson NR, Pacy PJ. Post-prandial protein metabolism. BAILLIERE'S CLINICAL ENDOCRINOLOGY AND METABOLISM 1996; 10:533-49. [PMID: 9022950 DOI: 10.1016/s0950-351x(96)80696-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Current post-prandial studies of amino acid metabolism and utilization are consistent with a feeding mechanism mediated primarily by insulin and amino acids, with the balance between protein conservation and net deposition dependent on the amino acid supply [1-13C]leucine post-prandial kinetic tracer studies of leucine oxidation, non-oxidative disappearance and endogenous appearance allow study of the regulation of whole-body amino acid oxidation, protein synthesis and proteolysis. On the basis of these studies it appears that for leucine oxidation, the main determinant of the efficiency of protein utilization, the overriding regulatory influence is substrate availability rather than insulin. Such substrate sensitivity is manifest throughout the physiological range of insulin down to the lowest insulin levels observed suggesting that a basal insulin need is not an important part of regulation of this important catabolic pathway. The key protein turnover response is an inhibition of proteolysis sufficient to limit any increases in amino acid levels thus limiting any increase in amino acid oxidation. It appears that the influences of amino acids and insulin on proteolysis are separate and additive and may both be receptor mediated so that extracellular amino acid levels can regulate intracellular levels. It is likely that protein synthesis is regulated by intracellular amino acid levels but post-prandial stimulation through increases in amino acid levels appears to be unhelpful because of parallel increases in amino acid oxidation. Evidence for any influence of insulin on protein synthesis has yet to be unequivocally identified.
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Affiliation(s)
- D J Millward
- Centre for Nutritional and Food Safety, School of Biological Sciences, University of Surrey, Guildford, UK
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Tessari P, Zanetti M, Barazzoni R, Vettore M, Michielan F. Mechanisms of postprandial protein accretion in human skeletal muscle. Insight from leucine and phenylalanine forearm kinetics. J Clin Invest 1996; 98:1361-72. [PMID: 8823301 PMCID: PMC507562 DOI: 10.1172/jci118923] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The relative role of protein synthesis and degradation in determining postprandial net protein deposition in human muscle is not known. To this aim, we studied forearm leucine and phenylalanine turnover by combining the arteriovenous catheterization with tracer infusions, before and following a 4 h administration of a mixed meal in normal volunteers. Forearm amino acid kinetics were assessed in both whole blood and plasma. Fasting forearm protein degradation exceeded synthesis (P < 0.01) using either tracer, indicating net muscle protein loss. The net negative forearm protein balance was quantitatively similar in whole blood and in plasma. After the meal, forearm proteolysis was suppressed (P < 0.05- < 0.03), while forearm protein synthesis was stimulated (P < 0.05- < 0.01). However, stimulation of protein synthesis was greater (P < 0.05- < 0.01) in whole blood (leucine data: +50.4 +/- 7.8 nmol/min x 100 ml of forearm; phenylalanine data: +30.4 +/- 11.6) than in plasma (leucine data: +17.8 +/- 5.6 nmol/min x 100 ml of forearm; phenylalanine data: +5.7 +/- 2.1). Consequently, the increment of net amino acid balance was approximately two to fourfold greater (P < 0.04- < 0.03) in whole blood than in plasma. In conclusion, meal ingestion stimulates forearm protein deposition through both enhanced protein synthesis and inhibited proteolysis. Plasma data underestimate net postprandial forearm protein synthesis, suggesting a key role of red blood cells and/or of blood mass in mediating mealenhanced protein accretion.
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Affiliation(s)
- P Tessari
- Department of Metabolic Diseases, University of Padova, Italy
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Young VR, Yu YM, Fukagawa NK. Protein and energy interactions throughout life. Metabolic basis and nutritional implications. ACTA PAEDIATRICA SCANDINAVICA. SUPPLEMENT 1991; 373:5-24. [PMID: 1927528 DOI: 10.1111/j.1651-2227.1991.tb18147.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We review selected aspects of the interactions between protein and energy in human metabolism and nutrition. Following a short account of the underlying metabolic basis for the effects of energy on protein metabolism, the contribution made by whole body protein turnover to the metabolic rate is discussed, including the relationship between protein turnover and energy metabolism at different phases of life. The effects of changes in energy metabolism and intake on the nitrogen economy of the host are also reviewed briefly and we explore the relationship between amino acid oxidation and requirements for indispensable amino acids. Interactions between energy and protein metabolism need to be investigated in greater detail and also they must be considered in relation to further attempts to establish more precisely energy and amino acid requirements of people under various circumstances.
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Affiliation(s)
- V R Young
- Laboratory of Human Nutrition, Massachusetts Institute of Technology, Cambridge
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Millward DJ, Price GM, Pacy PJ, Halliday D. Maintenance protein requirements: the need for conceptual re-evaluation. Proc Nutr Soc 1990; 49:473-87. [PMID: 2080179 DOI: 10.1079/pns19900056] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- D J Millward
- Nutrition Research Unit, London School of Hygiene & Tropical Medicine
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