Nutritional Intervention for Age-Related Muscular Function and Strength Losses

描述(申请人提供)：骨质疏松症，定义为与年龄相关的肌肉质量、肌肉功能和力量的丧失，在老年人中非常普遍。骨质疏松症是美国快速增长的老龄化人口面临的最大公共卫生问题之一，并导致跌倒、骨折和相关疾病的发生率增加。我们实验室以及许多其他实验室之前的观察已经证明，2-羟基-2-甲基丁酸酯(HMB)单独或与其他氨基酸联合使用在增强年轻运动员的肌肉力量和功能方面具有有效性。我们最近在一项为期一年的前瞻性研究中证明了HMB与另外两种氨基酸精氨酸和赖氨酸的结合在增加老年男性和女性肌肉质量方面是有效的。当分析数据(初步结果)时，我们证明了这一人群中25-OH维生素D3的水平与肌肉力量的改善水平之间存在密切的相关性。我们注意到，血浆25-OH维生素D3水平为30 ng/ml的个体表现出补充了HMB和两种氨基酸的肌肉力量增加，而血浆25-OH维生素D3水平为30 ng/ml的个体则没有。这些数据构成了我们目前假设的基础，即HMB和维生素D补充剂的组合将是协同的，并将导致整体肌肉力量、功能和肌肉质量的显著增强。我们提出这些第一阶段和第二阶段的研究来证明我们的假设。第一阶段研究将测试HMB和维生素D联合使用的短期(12周)疗效，以预防和逆转老年人的肌肉石棺减少以及相关的肌肉力量和功能丧失。我们计划招募100名男性和女性，他们将被分配到四种饮食治疗中的一种：(1)对照组；(2)HMB(钙盐)，3.0克/天；(3)2,000国际单位维生素D；(4)HMB，3.0克/天+2,000国际单位维生素D。受试者将接受每周3天的锻炼计划，并将每隔4周测量身体成分和力量。我们希望在这项简短的研究中证明HMB和维生素D之间的协同作用。第二阶段将测试这种HMB和维生素D的协同组合在增强老年人肌肉力量和功能方面的长期(12个月)效果，从而改善生活质量。第二阶段将包括像第一阶段一样的锻炼手臂，但也将包括非锻炼手臂，因为许多老年人不参加锻炼计划。除了身体成分、功能和力量数据外，还将进行肌肉活组织检查，并进行肌肉纤维和蛋白质组分析。我们预计，产生的数据将导致进一步的研究，寻找涉及老年人肌肉和肌肉功能丧失的机制(S)。在长达一年的研究中，肌肉力量和肌肉功能的改善以及身体成分的改善将用于销售一种含有HMB和维生素D的产品。 与公共健康相关：目前的估计将很大一部分美国老年人口置于跌倒的风险中，并可能患上疾病。在这些跌倒中，有很大比例与肌肉力量和功能的下降直接相关。由于很大一部分老年人口面临维生素D缺乏的风险，一种纠正这种缺乏并专门针对肌肉力量、功能和质量的产品可能会显著改善健康，提高生活质量，特别是有助于降低这一群体的跌倒和受伤发生率。此外，根据所有年龄段普遍存在的维生素D缺乏症的发生率，我们预计年轻人群也将从类似的补充中受益。

DESCRIPTION (provided by applicant): Sarcopenia, defined as age related loss of muscle mass and muscle function and strength, is very prevalent among the elderly. Sarcopenia is one of the largest public health problems facing a rapidly increasing, aging population in the United States and leads to increased incidence of falls, fractures and associated morbidities. Previous observations from our laboratory, as well as from many other laboratories, have demonstrated the efficacy of 2-hydroxy-2-methylbutyrate (HMB) alone or in combination with other amino acids in enhancing muscle strength and function in young athletes. We have recently demonstrated that the combination of HMB with two other amino acids, arginine and lysine, was effective in increasing muscle mass in elderly men and women during a year-long prospective study. When analyzing the data (Preliminary Results), we demonstrated a close correlation between the levels of 25-OH Vitamin D3 in this population and the level of improvement in muscle strength. We noted that individuals with plasma 25-OH Vitamin D3 levels >30 ng/ml manifested muscle strength gains supplemented with HMB and two amino acids, while those with plasma 25- OH Vitamin D3 of <30 ng/ml did not. These data form the basis of our current hypothesis that the combination of HMB and Vitamin D supplementation will be synergistic and will result in significant enhancements in overall muscle strength, function and muscle mass. We propose these Phase I and Phase II studies to prove our hypothesis. The Phase I study will test the short-term (12-wk) efficacy of a combination of HMB and Vitamin D to prevent and reverse muscle sarcopenia and the associated losses of muscular strength and functionality in older adults. We plan to recruit 100 men and women who will be assigned to one of four dietary treatments: (1) Control; (2) HMB (calcium salt), 3.0 g/day; (3) 2,000 IU Vitamin D; and (4) HMB, 3.0 g/d + 2,000 IU Vitamin D. The subjects will undergo a 3-day per week exercise program, and body composition and strength will be measured at four week intervals. We expect to demonstrate the synergy between HMB and Vitamin D in this short study. Phase II will test the long-term (12-mos) efficacy of this synergistic combination of HMB and Vitamin D on the enhancement of muscle strength and functionality in the elderly, thus leading to improved quality of life. Phase II will include an exercise arm just like Phase I, but will also include a non-exercise arm because many elderly adults do not participate in an exercise program. In addition to body composition and function and strength data, muscle biopsies will be obtained and muscle fiber and proteomic analysis will be performed. We anticipate that the data generated will lead to further research looking at mechanism(s) involved in loss of muscle and muscle function in the elderly. Improvement in muscle strength and muscle function as well as improvements in body composition over the year-long study will be used to market a product containing HMB and Vitamin D. PUBLIC HEALTH RELEVANCE: Current estimates place a large portion of the older U.S. populous at risk for falls with potential morbidities. A large percentage of these falls are directly related to decreased muscle strength and function. Since a significant portion of the older population is at risk of having a Vitamin D deficiency, a product that corrects such deficiencies and specifically targets muscle strength, function, and mass is likely to produce significant improvements in health, improve the quality of life, and in particular, help to decrease the incidence of falls and injury in this group. Moreover, based upon the incidence of widespread Vitamin D deficiency in all ages, we anticipate the younger population will also benefit from similar supplementation.