Impact of protein and alkali supplementation on skeletal muscle in older adults

项目总结 骨骼肌丧失和损伤--衰老过程的显著特征--会导致身体残疾。 有可信的证据表明，改变饮食的成分，主要是蛋白质摄入量和酸碱平衡， 可以改善老年人的肌肉健康指数，从而转化为身体残疾的减少。一个 越来越多的研究表明，通过补充乳清蛋白来增加蛋白质摄入量可能会有所裨益 老年人的肌肉健康。然而，一个主要的担忧是高蛋白会导致饮食中大量的酸负荷。 从蛋白质的分解到产酸的副产物，这反过来又会促进肌肉的降解 尤其是在年龄相关的肾脏酸排泄量下降的老年人中。因此，我们的假设是 饮食中蛋白质的量(合成代谢成分)和饮食的净酸负荷之间的平衡 (分解代谢成分)在一定程度上决定了饮食作为一个整体是否对 肌肉。我们小组的初步数据表明，每天一次碳酸氢钾(KHCO3) 营养补充剂可改善绝经后妇女的下肢肌力。根据我们的初步数据， 我们计划进行一项随机、双盲、安慰剂对照、2x2因素研究，在该研究中，久坐的男性 而65岁及以上的低蛋白饮食女性将被纳入其中。参与者将被分配到一个 共四组：添加或不添加碳酸氢钾的乳清蛋白补充剂(将蛋白质摄入量提高到1.5g/kg/d) 81 mmo1/d或补充等卡路里的安慰剂，加或不加KHCO3 81 mmo1/d，共24周。初级阶段 结果是腿部肌肉力量。次要结果是腿部肌肉耐力， 体能、瘦体重和24小时尿氮排泄量。这些数据的24周变化 比较4组患者的治疗效果。我们的中心假设是较高的蛋白质摄入量加上 中和碱性盐会对老年人的肌肉表现和质量产生相加的影响 单单是干预。如果成功，这项研究可能会导致对老年人的饮食建议的范式转变 以减少身体残疾。到2040年，五分之一的美国成年人将超过65岁，这是一种安全的饮食干预措施 这将减少与年龄相关的肌肉骨骼衰退，这将是预防我们衰老的重要健康步骤 社会。

PROJECT SUMMARY Skeletal muscle loss and impairment – prominent features of the aging process – lead to physical disability. There is plausible evidence that altering components of the diet, mainly protein intake and acid/base balance, may improve indices of muscle health in older adults and thus translate to a reduction in physical disability. A growing number of studies suggest that increasing protein intake using a whey protein supplement may benefit muscle health in older adults. However, a main concern is that high protein results in a large dietary acid load from the breakdown of protein to acidogenic byproducts, which could in turn promote muscle degradation particularly in older adults with age-related declines in renal excretion of acid. Thus, our hypothesis is that the balance between the amount of protein in the diet (anabolic component) and the net acid load of the diet (catabolic component) in part determines whether the diet as a whole has a net anabolic or catabolic effect on muscle. Preliminary data from our group have suggested that a daily potassium bicarbonate (KHCO3) supplement improved lower extremity muscle power in postmenopausal women. Based on our preliminary data, we plan to conduct a randomized, double-blind, placebo-controlled, 2x2 factorial study in which sedentary men and women age 65 and older on baseline lower protein diets will be enrolled. Participants will assigned to one of four groups: either a whey protein supplement (to raise protein intake to 1.5 g/kg/d) with or without KHCO3 81 mmol/d or an isocaloric placebo supplement with or without KHCO3 81 mmol/d for 24 wks. The primary outcome is lower extremity muscle power. Secondary outcomes are lower extremity muscle endurance, physical performance, lean mass, and 24-hr urinary nitrogen excretion. Twenty-four-week changes in these outcomes will be compared in the 4 groups. Our central hypothesis is that higher protein intake plus a neutralizing alkaline salt will have additive effects on muscle performance and mass in older adults to either intervention alone. If successful, this research could result in a paradigm shift in dietary advice to older adults to reduce physical disability. As 1 in 5 US adults will be over age 65 by year 2040, a safe dietary intervention that reduces age-related musculoskeletal decline will be an important preventative health step for our aging society.