DIETARY PROTEIN REQUIREMENTS OF ELDERLY MEN AND WOMEN

老年男性和女性的膳食蛋白质需求

基本信息

批准号：
6421077
负责人：
WAYNE W CAMPBELL
金额：
$ 40.27万
依托单位：
PURDUE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
1999
资助国家：
美国
起止时间：
1999-04-01 至 2003-02-28
项目状态：
已结题

项目摘要

The current mean protein requirement for adults of all ages is 0.6 g protein.kg-1.d-1, with a suggested safe protein intake set a 0.75 g protein.kg-1.d-1 in 1985 by the Joint FAO/WHO/UNU Expert Consultation (WHO) and at 0.8 g protein.kg-1.d-1 (the Recommended Dietary Allowance, RDA) in 1989 by the US National Research Council (NRC). Nitrogen balance (NBal) is the current standard, and only accepted, method used to establish total protein (nitrogen) requirements and allowances. Both the WHO and NRC indicated that insufficient data were available from studies done with elderly subjects to determine a protein requirement with confidence. Thus, the current recommendations for elderly people are largely extrapolations from NBal studies done in young men. Yet, sarcopenia (the age-related loss of muscle mass), and changes in physical activity, food intake, and the frequency of disease in elderly people may contribute to an altered protein requirement in this population. Limited NBal data from our laboratory suggest that the protein requirement of elderly people is actually 50% higher than the accepted requirement. Other researchers using 1-13C-leucine balance studies, recently suggested that the protein requirement of elderly people is similar to or less than that of younger adults. We have shown that adherence to a low-protein diet by elderly women for 10 weeks adversely effected fat-free mass, muscle mass, and muscle strength and function. Our preliminary data now indicates that elderly people who consumed eucaloric diets providing the RDA for protein for 14 weeks lost fat-free mass and muscle mass, and gained body fat. The public health implications of this accommodation to the protein RDA are largely unknown. This research will, for the first time, test whether the mean protein requirement of 7-85 year-old people is greater than that of 18-30 year- old people. Women and men will be studied separately. A double-blinded NBal study design will be used during four separate 7 day NBal trials. Strict dietary control will be maintained by giving the subjects energy- balanced menus with either 0.40, 0.60, 0.80 or 1.00 g protein.kg-1.d- 1.1-13C- leucine balance studies will be done at each protein intake to assess age related differences in leucine oxidation, utilization oxidation, utilization, incorporation into albumin and the apparent protein requirement. Clinical markers of visceral protein status will also be measured. The results of the study will contribute to our understanding of the metabolism and requirement for protein, and will be critical to establishing a RDA for protein of elderly people.

目前所有年龄段成年人的平均蛋白质需求量为 0.6 克 Protein.kg-1.d-1，建议安全蛋白质摄入量设定为 0.75 g 1985年由FAO/WHO/UNU联合专家磋商会确定的蛋白质.kg-1.d-1 (WHO) 和 0.8 g 蛋白质.kg-1.d-1（推荐膳食摄入量， RDA）于 1989 年由美国国家研究委员会（NRC）提出。氮平衡 (NBal) 是当前标准且唯一被接受的方法，用于确定总蛋白质（氮）的需求和限额。两者都 WHO 和 NRC 表示研究数据不足对老年受试者进行研究以确定蛋白质需求信心。因此，目前对老年人的建议是很大程度上是根据在年轻男性中进行的 NBal 研究推断的。然而，肌肉减少症（与年龄相关的肌肉质量损失）以及肌肉减少症老年人的体力活动、食物摄入量和疾病频率人们可能会导致蛋白质需求的改变人口。我们实验室有限的 NBal 数据表明该蛋白质老年人的要求实际上比公认的高出50% 要求。其他研究人员使用 1-13C-亮氨酸平衡研究，最近提出老年人的蛋白质需要量是与年轻人相似或低于年轻人。我们已经证明老年妇女坚持低蛋白饮食 10 周会产生不利影响影响去脂质量、肌肉质量以及肌肉力量和功能。我们现在的初步数据表明，消费的老年人提供 RDA 蛋白质的无脂饮食 14 周质量和肌肉质量，并增加了身体脂肪。公共卫生这种调节对蛋白质 RDA 的影响很大程度上是未知。这项研究将首次测试平均蛋白质是否 7-85岁人群的需求大于18-30岁人群老年人。女性和男性将被分开研究。双盲 NBal 研究设计将在四次独立的 7 天 NBal 试验中使用。通过给予受试者能量来维持严格的饮食控制含有 0.40、0.60、0.80 或 1.00 g 蛋白质的均衡菜单.kg-1.d- 1.1-13C-亮氨酸平衡研究将在每次蛋白质摄入时进行评估亮氨酸氧化、利用的年龄相关差异氧化、利用、掺入白蛋白和表观蛋白质需求量。内脏蛋白质状态的临床标志物将也可进行测量。研究结果将有助于我们了解蛋白质的新陈代谢和需求，并将对于制定老年人蛋白质每日摄入量至关重要。