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; 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（由申请人提供）：骨质疏松症和骨质减少症是影响超过4400万美国人（主要是老年妇女）的主要健康问题。营养在骨骼健康中起着至关重要的作用，但其在骨质流失的发病机理和预防中的作用尚不完全理解。我们发现饮食蛋白是钙稳态的主要调节剂，但其对骨骼健康的影响仍然存在争议。 众所周知，增加的饮食蛋白会增加泌尿钙的排泄，并且一种广泛持有的观点是，这种额外的钙部分起源于骨骼。然而，最近的流行病学研究发现，较高的蛋白质摄入量与较高（不是较低）骨矿物质密度和骨质流失率较低（不是更高）有关。使用钙动力学方法论，我们发现，当健康女性中饮食蛋白增加时，肠道钙的吸收会大大增加，并且几乎占尿钙的增加。此外，当女性消耗高蛋白质饮食时，起源于骨骼的尿钙的百分比会减少，并且骨转换也会略有减少。我们假设一种蛋白质补充剂添加到健康老年女性习惯性低正常蛋白质饮食的饮食中，将改善骨骼健康和骨代谢的荷尔蒙指数（与安慰剂控制相比）。 为了检验这一假设，我们将使用耶鲁大学和康涅狄格大学健康中心的一般临床研究中心进行18个月，双盲，安慰剂对照的饮食蛋白补充试验。 200名健康的女性至少60岁。年龄将从康涅狄格州中部招募。受试者将被招募，他们自然会消耗饮食蛋白（0.6-1 g/kg）的中等低（但充分）的受试者。 （大约30-40％的美国妇女60岁以上属于这一组）。基线测量后，受试者将被随机分配以接受安慰剂（麦芽糊精）或40 g蛋白补充剂18个月。如DEXA所评估的那样，该试验中的主要结局指标是脊柱骨密度。次要结局将包括脊柱上的BMD和通过QCT测量的髋关节，矿物质稳态和骨骼更新的血清测量以及对身体性能的评估。这些研究将更好地为饮食蛋白质的建议提供最佳的骨骼健康建议，如果我们的假设是正确的，则为年龄相关的骨质流失提供了一种新的治疗方法。