IMPACT OF A PROTEIN SUPPLEMENT ON BONE MASS IN OLDER WOMEN

蛋白质补充剂对老年女性骨量的影响

• 批准号: 7194429
• 负责人: KARL Leonard INSOGNA
• 金额: $ 56.09万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-28 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7194429
• 关键词: bone; calcium; clinical research; diet; dietary proteins; health; placebos; proteins

DESCRIPTION (provided by applicant): Osteoporosis and osteopenia are major health problems affecting over 44 million Americans, primarily older women. Nutrition, plays a critical role in bone health but its role in the pathogenesis and prevention of bone loss is incompletely understood. We have found that dietary protein is a major regulator of calcium homeostasis, yet its impact on skeletal health remains controversial. Increasing dietary protein is known to increase urinary calcium excretion and a widely held view is that this extra calcium originates, in part, from bone. However, recent epidemiologic studies have found that higher protein intakes are associated with higher (not lower) bone mineral density and lower (not higher) rates of bone loss. Using calcium kinetic methodology, we have found that when dietary protein is increased in healthy women, intestinal calcium absorption increases significantly and accounts for almost all of the increase in urinary calcium. Further, when women consumed a high protein diet, the percentage of urinary calcium originating from bone is reduced and bone turnover is also slightly reduced. We hypothesize that a protein supplement added to the diets of healthy older women with habitually a low-normal protein diet, will improve bone health and hormonal indices of bone metabolism (in comparison to a placebo control). To test this hypothesis, we will conduct an 18-month, double-blind, placebo-controlled, dietary protein supplementation trial using the General Clinical Research Centers at Yale University and the University of Connecticut Health Center. Two hundred healthy women at least 60 yrs. of age will be recruited from central Connecticut. Subjects will be enrolled who naturally consume a moderately low (yet adequate) level of dietary protein (0.6-1 g/kg). (Approximately 30-40% of US women over the age of 60 y fall into this group). After baseline measurements, subjects will be randomized to receive either a placebo (maltodextrin) or a 40 g protein supplement for 18 months. The primary outcome measure in this trial is spinal bone density as assessed by DEXA. Secondary outcomes will include BMD at the spine and hip measured by QCT, serum measures of mineral homeostasis and bone turnover, and an assessment of physical performance. These studies will better inform dietary protein recommendations for optimal skeletal health and, if our hypothesis is correct, provide a new therapeutic approach to age-related bone loss.

描述(申请人提供)：骨质疏松症和骨量减少是影响4400万美国人的主要健康问题，主要是老年女性。营养在骨骼健康中起着至关重要的作用，但其在发病机制和预防骨丢失中的作用尚不完全清楚。我们已经发现，饮食蛋白质是钙稳态的主要调节因素，但它对骨骼健康的影响仍然存在争议。 众所周知，增加膳食蛋白质会增加尿钙排泄量，一个普遍的观点是，这种额外的钙部分来自骨骼。然而，最近的流行病学研究发现，更高的蛋白质摄入量与更高(而不是更低)的骨密度和更低(而不是更高)的骨丢失率相关。利用钙动力学方法，我们发现，当健康女性的膳食蛋白质增加时，肠道钙吸收显著增加，并几乎解释了尿钙增加的全部原因。此外，当女性摄入高蛋白饮食时，源自骨骼的尿钙百分比减少，骨骼转换率也略有下降。我们假设，在习惯于低正常蛋白质饮食的健康老年女性的饮食中添加蛋白质补充剂，将改善骨骼健康和骨代谢的激素指数(与安慰剂对照组相比)。 为了验证这一假设，我们将利用耶鲁大学的普通临床研究中心和康涅狄格大学健康中心进行一项为期18个月的双盲、安慰剂对照的饮食蛋白质补充试验。200名60岁以上的健康女性。年龄将从康涅狄格州中部招募。受试者将被纳入自然摄入中等低(但足够)的饮食蛋白质水平(0.6-1克/公斤)的受试者。(60岁以上的美国女性中约有30%-40%属于这一群体)。在基线测量后，受试者将被随机接受安慰剂(麦芽糊精)或40g蛋白质补充剂，为期18个月。在这项试验中，主要的结果测量是由DEXA评估的脊柱骨密度。次要结果将包括QCT测量脊柱和髋部的BMD，血清矿物质平衡和骨转换的测量，以及体能表现的评估。这些研究将为最佳骨骼健康的饮食蛋白质推荐提供更好的信息，如果我们的假设是正确的，那么将提供一种新的治疗方法来治疗与年龄相关的骨丢失。