加强营养和运动 防治肌肉衰减征

什么叫肌肉衰减征肌肉衰减是一个既古老又陌生的医学问题。现代医学之父希波克拉底早在2000多年前就清楚地描述:人体肌肉被消耗成水,肩、颈、胸和大腿的肌肉逐渐萎缩消失……这种疾病是致命的。肌肉衰减在老年人     

老年人肌肉衰减情况及肉类饮食对其影响的研究

将60~69岁、70~79岁、≥80岁三个年龄阶段的老年人分为肌肉衰减组、正常组,调查分析了老年人肌肉衰减与肉类饮食等影响因素的关系,揭示肉类饮食、运动状况和老年人肌肉衰减的关系,从食品摄入角度为干预老年人肌肉衰减提供依据。结果表明:从总体上看,与正常组比较发现,肌肉衰减组老年人在性别、BMI(身体质量指数)上差异极显著(P<0.01);组内比较发现,肌肉衰减组三个年龄段老年人随年龄增长其肌肉衰减程度呈上升趋势,SMI(骨骼肌质量指数)下降;膳食状况与运动状况分析发现,肌肉衰减组三个年龄段中部分年龄段老年人在肉类及其蛋白摄入量、畜禽类及其蛋白摄入量、运动量分类上与正常组老年人有显著差异(P<0.05),并且其肌肉衰减率随着肉类及其蛋白摄入量、畜禽类及其蛋白摄入量、运动量分类值的增加而呈递减趋势(P<0.05);肌肉衰减与肉类及其蛋白摄入量有关(β=-2.633、P<0.05;β=-2.216、P<0.05),肉类及其蛋白摄入量为老年人肌肉衰减的保护因素(OR<1);主成分分析发现肉类、抗阻运动量的排序(2、3)和肉类蛋白、抗阻运动量(2、1)排序均靠前,SMI与肉类及其蛋白摄入量、畜禽肉及其蛋白摄入量有较强的相关性,指标之间距离较近。结论:老年人肌肉衰减受年龄、性别、BMI、肉类饮食、运动状况等因素影响,适当增加老年人肉类摄入量(特别是畜禽肉)、抗阻运动量,有助于改善老年人的肌肉衰减。     

抵抗骨骼肌衰减的活性因子及其食品现状

日益普遍的骨骼肌衰减现象对人们的正常生活造成了种种不便,人们对机体的健康和年轻态的追求也越来越强烈,在各种干预治疗作用的同时,食品在抵抗肌肉衰减方面也具有重要作用。本文概述肌肉衰减产生的机制,以及国内外已知具有对抗肌肉衰老作用的活性因子,分析了市场上已有的具有抗肌肉衰减功能的食品现状,并对抗肌肉衰减功能性食品的发展进行了展望,为抗肌肉衰减功能性食品的开发奠定了理论基础。     

乳品蛋白质有助预防肌肉衰减

全球人口正趋老龄化，尤其是发达国家如德国、日本和美国等。而在发展中国家如中国、印度，这一问题也日益严重。预计到2050年，全球60岁以上的人口将超过20亿，而这其中有5亿人口在中国。这将产生一个巨大的隐忧，因为随着年龄的增加，肌肉量和功能将大幅度下降，人们的身体状况也随之改变。这种肌肉的损失称为“肌肉衰减综合征”，     

老年人肌少性肥胖的机制与运动营养调控研究进展

老年人肌少性肥胖(sarcopenic obesity,SO)是一种伴随着肥胖的骨骼肌质量和功能下降的老年性疾病,多发于老年人群而严重影响其生活质量。大量研究结果表明随着年龄的增长,即使体质量不变,老年人身体组成也会逐渐改变,肌肉质量功能下降,脂肪比例上升且主要堆积在肌肉组织、内脏器官,整体表现为肌肉脂肪量上升、炎症因子增多、生长激素水平下降、营养摄入不足、活动量降低、神经元功能下降以及胰岛素抵抗等,这些现象都与SO相关。从分子水平阐述其相关机制,研究者发现骨骼肌蛋白质合成与降解、骨骼肌糖脂代谢以及相关细胞因子均参与SO代谢通路的调控。运动干预、热量限制及蛋白质、VD、β-羟基-β-甲基丁酸盐、肌酸和乳清蛋白的摄入均可在一定程度上起到防治SO的效果。由于国内外对于SO的判断标准、发病机制以及防治手段仍不统一,给SO研究带来了较大难度。本文对国内外最新研究报道进行整理总结,从SO的定义、引起因素、涉及的细胞信号调控通路以及防治策略(运动或营养食品干预)等方面进行了综述,为SO治疗提供新思路。     

老年肌肉减少症防治中的营养干预

肌肉减少症是与年龄相关的肌肉质量、力量和体能的下降。减缓或推迟其发生、发展的唯一途径就是运动营养干预。老年人的消化吸收功能减退,给膳食营养补充带来困难,而特殊营养品的使用成为必不可少的有效途径。本文主要针对防治老年肌少症的蛋白质、氨基酸、维生素D、钙、抗氧化剂、植物调理剂等营养品补充作详尽的阐述。     

老年人肌肉衰减变化与健康研究

当前社会老龄化越来越严重,老年人的身体健康也成为研究的重点。老年人的肌肉反应能力和平衡能力都有一定的减退,容易出现摔跤的情况。早期人们认为这是因为人上了年纪之后骨质疏松导致的。但是当前越来越多的研究表明,出现这种情况还有一个重要的原因就是老年人的肌肉衰减,导致老年人出现体虚乏力,容易摔跤的情况。本文将对于老年人肌肉衰减变化以及健康情况进行相关的研究。     

饮食模式与新陈代谢

人体新陈代谢伴随年龄的增长而下降，这一原理显而易见。科学家们正在研究并且已经提出了有助于随年龄增长而重新使体内新陈代谢率活跃的途径。在女性的成年期间，每年体重增加半斤，如果不采取措施抗御荷尔蒙的大幅度波动、肌肉损失和压力，则足以使其在50岁时增加40多斤体重。     

结合低场核磁共振分析反复冻融处理对肉鸡不同部位肌肉品质的影响

利用低场核磁共振（low-field nuclear magnetic resonance,LF-NMR）技术研究反复冻融处理对肉鸡不同部位肌肉品质的影响。结果表明,反复冻融期间pH值变化不显著（P＞0.05）。随着冻融次数的增加,肉鸡胸肉和腿肉解冻汁液损失显著下降（P＜0.05）,硫代巴比妥酸反应物质（thiobabituric acid reactive substance,TBARS）值显著增大,总蛋白溶解度以及肌原纤维小片化冻融初期呈现上升趋势,总水分含量均逐渐降低。低场核磁共振T2弛豫时间分析显示,其自由水占比显著下降（P＜0.05）。以上结果说明反复冻融使解冻汁液损失伴随自由水比例显著下降而逐步降低,由于肌肉pH值保持稳定,推测反复冻融过程中反复形成的冰晶对肌肉微观结构的破坏,尤其对肌原纤维蛋白质溶解度的影响起到一定的作用。     

基于内源酶活性变化的冷藏哈氏仿对虾肌肉品质研究

目的:探究冷藏条件下哈氏仿对虾内源酶活性及肌肉品质特性的变化情况。方法:以哈氏仿对虾为对象,在0 ℃冷藏0、2、4、6 d,比较分析完整虾组和去头虾组肌肉的质构、TCA-可溶性肽、肌原纤维蛋白含量及其小片化指数以及虾头与肌肉中各种内源酶活性的变化规律。结果:随着冷藏时间的延长,两组虾肌肉中TCA-可溶性肽含量及肌原纤维小片化指数均呈现上升趋势;肌原纤维蛋白含量呈下降趋势,完整虾组和去头虾组肌肉在冷藏6 d后分别降低了56.65%和44.63%;而两组虾肉的硬度和弹性也始终呈现出下降趋势。在冷藏过程中,完整虾组虾头中胰蛋白酶活性逐渐下降,而其肌肉中活性则不断增加,去头虾组肌肉中该酶活缓慢下降,完整虾组虾头及肌肉、去头虾组肌肉中分别变化了16.9%、68.8%和15.2%;钙蛋白酶活性在两组肌肉中均随冷藏时间延长而不断下降,其中以完整虾组肌肉下降幅度较明显;在冷藏过程中组织蛋白酶B、D、H及L活性变化情况有所不同,其中去头虾组肌肉中4种组织蛋白酶活性整体高于完整虾组;两组虾肌肉中4种组织蛋白酶的活性在各亚细胞组份中,随着冷藏时间延长而逐渐下降,且完整虾组中活性高于去头虾组。结论:在冷藏过程中,去头虾组肌肉的品质特性优于完整虾组,且完整虾组中各种内源酶活性相对高于去头虾组,因此以去虾头方式进行贮藏更利于对虾肉品质的保障。     

衰老性肌萎缩症的膳食营养调控研究进展

衰老性肌萎缩症是与年龄相关的肌肉质量下降和力量减弱症,因其在当今社会中的患病率日益提高而受到关注。衰老性肌萎缩症造成的不良后果包括使患者丧失独立性,增加健康成本,降低生活质量。随着人口的不断老龄化,包括衰老性肌萎缩症在内的骨骼肌疾病的罹患率逐渐提高。目前已经提出许多机制作为衰老性肌萎缩症发病的潜在因素,包括衰老性厌食症、蛋白质失衡和氧化应激。目前,对衰老性肌萎缩症的预防和治疗方法尚未达成共识。在这种情况下,营养和运动干预相结合似乎是目前可用于治疗衰老性肌萎缩症的最有效策略。本文将总结和讨论衰老性肌萎缩症的定义和发病机制、目前在营养方面治疗衰老性肌萎缩症的对策、相关营养食品对衰老性肌萎缩症的作用机制,并提出保持肌肉质量和功能的新型营养策略。最后,阐述合理化饮食方式结合运动干预的协同效应,以期为衰老性肌萎缩症的预防和治疗提供更佳选择。     

Nutrient-rich meat proteins in offsetting age-related muscle loss

From a health perspective, an underappreciated consequence of the normal aging process is the impacts that the gradual loss of skeletal muscle mass, termed sarcopenia, has on health beyond an effect on locomotion. Sarcopenia, refers to the loss of muscle mass, and associated muscle weakness, which occurs in aging and is thought to proceed at a rate of approximately 1% loss per year. However, periods of inactivity due to illness or recovery from orthopedic procedures such as hip or knee replacement are times of accelerated sarcopenic muscle loss from which it may be more difficult for older persons to recover. Some of the consequences of age-related sarcopenia are easy to appreciate such as weakness and, eventually, reduced mobility; however, other lesser recognized consequences include, due to the metabolic role the skeletal muscle plays, an increased risk for poor glucose control and a predisposition toward weight gain. What we currently know is that two stimuli can counter this age related muscle loss and these are physical activity, specifically resistance exercise (weightlifting), and nutrition. The focus of this paper is on the types of dietary protein that people might reasonably consume to offset sarcopenic muscle loss.     

Nutrition and sarcopenia: A review of the evidence of nutritional influences

Prevention of age related decline in muscle mass and strength is a key strategy to keeping physical capacity in older age and allowing independent living. To emerge preventive strategies, a better understanding is required of life style factors that impacts on sarcopenia. However, since muscle mass and strength in later life depend on both the rate of muscle loss and the peak achieved in early life, attempts to prevent sarcopenia also require considering diet through the life course and the potential benefits of early interventions. Optimizing diet and nutrition status during the life may be an important strategy to preventing sarcopenia and enhancing physical ability in older age.     

Supplemental Protein in Support of Muscle Mass and Health: Advantage Whey

Skeletal muscle is an integral body tissue playing key roles in strength, performance, physical function, and metabolic regulation. It is essential for athletes to ensure that they have optimal amounts of muscle mass to ensure peak performance in their given sport. However, the role of maintaining muscle mass during weight loss and as we age is an emerging concept, having implications in chronic disease prevention, functional capacity, and quality of life. Higher‐protein diets have been shown to: (1) promote gains in muscle mass, especially when paired with resistance training; (2) spare muscle mass loss during caloric restriction; and (3) attenuate the natural loss of muscle mass that accompanies aging. Protein quality is important to the gain and maintenance of muscle mass. Protein quality is a function of protein digestibility, amino acid content, and the resulting amino acid availability to support metabolic function. Whey protein is one of the highest‐quality proteins given its amino acid content (high essential, branched‐chain, and leucine amino acid content) and rapid digestibility. Consumption of whey protein has a robust ability to stimulate muscle protein synthesis. In fact, whey protein has been found to stimulate muscle protein synthesis to a greater degree than other proteins such as casein and soy. This review examines the existing data supporting the role for protein consumption, with an emphasis on whey protein, in the regulation of muscle mass and body composition in response to resistance training, caloric restriction, and aging.     

The role of exercise,milk, dairy foods and constituent proteins on the prevention and management of sarcopenia

Sarcopenia, an age‐related decline in muscle mass, is a burgeoning public health concern in the UK, with the number of people over the age of 65 expected to double by 2050. Resistance exercise is an effective intervention in its prevention and management. Increasing quantity and improving quality of dietary protein, by inclusion of high‐availability leucine, are also purportedly beneficial. Leucine is a key anabolic amino acid, found in dairy foods. A number of studies have investigated dairy foods in prevention of sarcopenia. This paper reviews interventions of exercise, amino acids including leucine, dairy protein and foods for prevention of sarcopenia.     

肌少症现状及蛋白质对其预防作用的研究进展

随着老龄化社会的到来，老年人的骨骼肌体积减少，肌力下降，易患肌肉减少症（Sarcopenia）。肌少症对于老年人的生活造成了许多不便，目前对于肌少症的对症医学治疗办法并不完善，了解其发病机制和治疗措施很有必要，其中补充蛋白质作为最健康、有效、便捷的方法受到人们的关注。本文总结了肌少症的发病机理和目前的预防治疗办法，阐明了蛋白质作用与肌少症的重要意义和蛋白质对于肌少症的预防治疗作用，为蛋白质在不同途径下应用与治疗肌少症奠定了理论基础。     

蒸制过程中大菱鲆肌肉理化特性、组织结构及蛋白特性变化

本研究以大菱鲆上背部肌肉为原料,考察其蒸制过程中脂肪含量、失水率、质量损失率、肌原纤维蛋白相 对提取率、组织结构、剪切力、硬度、咀嚼性、色度的变化,并对其肌原纤维蛋白和流失液蛋白相对分子质量变 化、鱼块Ca2＋Mg2＋-ATPase活力和总巯基含量的变化进行了检测。结果表明：随着蒸制时间的延长,大菱鲆鱼块的 失水率、质量损失率均不断增加,脂肪含量降低;肌原纤维蛋白相对提取率在蒸制开始2 min过程中下降明显,至 4 min时降至10%以下;Ca2＋Mg2＋-ATPase活力在蒸制2 min时降至最低;总巯基含量随蒸制时间延长呈先上升后下 降趋势,至1 min后基本不变。在蒸制过程中大菱鲆鱼块的微观组织结构由完整逐渐开始破裂;剪切力、硬度和咀 嚼性显著下降;亮度L*值显著升高（P＜0.05）,并在蒸制4 min后达到稳定状态;鱼块中蛋白的降解和流失使得流 失液中不同分子质量的蛋白逐渐增加。综上所述,限定规格（1.5 cm×1.5 cm×1.0 cm）大菱鲆鱼块在蒸制4 min时 可达到熟化且品质良好。     

Catechins enhance skeletal muscle performance

Abstract

Muscle-related disorders, such as sarcopenia and cachexia, caused by aging and chronic diseases can lead to the loss of muscle mass and strength to different degrees, severely affecting human health. Globally, tea is one of the three most popular beverages, and its major active ingredient catechins have been reported to delay muscular atrophy and enhance movement. However, currently, there is no systematic review to elaborate its roles and the associated mechanisms. This article reviews the (1) functions and mechanisms of catechins in the differentiation of myogenic stem cells, biogenesis of mitochondria, synthesis and degradation of proteins, regulation of glucose level, and metabolism of lipids in muscle cells; and (2) effect of catechins on the blood vessels, bones, and nerves that are closely related to the skeletal muscles. Catechins could prevent, mitigate, delay, and even treat muscle-related disorders caused by aging and diseases.     

New insights into body composition and health through imaging analysis. 2007 Ryley-Jeffs memorial lecture.

From calipers to magnetic resonance imaging (MRI), we have come a long way in our ability to analyze body composition. Some historical milestones are a reminder that many concepts in muscle and fat metabolism, and their measurement, have stood the test of time. However, newer imaging technology has improved our understanding of population heterogeneity in body composition, and the potential health problems associated with certain body composition phenotypes. Imaging analyses, such as dual energy X-ray absorptiometry, computed tomography, and MRI, have provided detailed characterization of the type and amount of fat deposited centrally (abdominal adipose tissue), the trajectory of losses in muscle tissue (sarcopenia), and the combination of low muscle mass/high fat mass (sarcopenic obesity). The last is a new emerging health concern because the presence of these two disproportionate tissue depots may have an additive effect on increasing morbidity. Ongoing measurement of body composition is needed, and preliminary research suggests this may have important nutritional implications.     

Iron chelation by digests of insoluble chicken muscle protein: the role of histidine residues

The role of histidine residues in the chelation of iron at neutral pH by peptides from chicken muscle was investigated to see if it could contribute to the effect of muscle tissue on iron absorption. When ferric iron was chelated by L ‐histidine at pH 6, the ratio of iron chelated to loss of reactive histidine was 1:1. Chelation of iron by soluble peptides in a digest of insoluble chicken muscle protein was accompanied by a small loss of reactive histidine (4–7%) in the peptides. When peptides were modified with diethylpyrocarbonate, increasing loss of histidine led to a progressive decrease in iron chelation. However, even 89% loss of histidine only reduced iron chelation by 30%. It was concluded that histidyl residues do contribute to iron chelation and therefore could by involved in the promotion of iron absorption by muscle tissue. However, other amino acid residues are likely to be involved. © 2000 Society of Chemical Industry