Dietary & non-dietary components of vitamin K metabolism

饮食

• 批准号: 7124359
• 负责人: SARAH Louise BOOTH
• 金额: $ 51.12万
• 依托单位: TUFTS UNIVERSITY BOSTON
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-30 至 2009-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7124359
• 关键词: age difference; blood lipoprotein transport; body composition; bone metabolism; clinical research; dietary supplements; human middle age (35-64); human old age (65+); human subject; lipid transport; nutrition related tag; photon absorptiometry; vitamin K; vitamin metabolism; young adult human (21-34)

DESCRIPTION (provided by applicant): Vitamin K has an emerging role in bone health. However, little is known about the vitamin K metabolism, particularly in regards to aging, and maintenance of bone mass. Such limited understanding about vitamin K metabolism currently impedes the ability to establish dietary recommendations for vitamin K, and interpret the results from recent clinical trials on vitamin K supplementation and bone health currently being conducted in primarily women of a narrow age group. The proposed study will be the first to assess the role of dietary and non-dietary factors that influence the response to measures of vitamin K status and bone turnover to vitamin K depletion and repletion in younger and older men and women. This study will also compare the absorption efficiency of vitamin K, relative to current vitamin K status. Men and women [21 younger (21-40y) and 21 older (60-80y)] will participate in a 65-d metabolic study, with a 5-d run-in period, followed by a 30 d dietary vitamin K restriction period (10 mu/ g/d), and ending with a 30 d dietary vitamin K supplementation period (500 mu g/d). Serial measurements of markers of vitamin K status (plasma phylloquinone, urinary Gla, serum %ucOC and plasma PIVKA-II) and bone turnover (serum osteocalcin and NTx) will provide information on their response to dietary manipulation of vitamin K for both age groups under identical controlled dietary conditions. A stable isotope tracer (deuterium-labeled vitamin K in collards) will be used to compare the absorption of vitamin K during a vitamin K-deplete state (21 d of dietary vitamin K depletion) to that of a vitamin K-replete state (21 d of dietary vitamin K repletion). Because vitamin K is transported in triglyceride-rich lipoproteins, which may vary among individuals due to differences in adiposity, measurement of body composition by DXA and plasma lipids (total and individual lipoproteins) will provide insight into the role of lipids in absorption and transport of vitamin K. The findings of the proposed study are critical for the interpretation of the epidemiologic and clinical data used to determine optimal intakes at which vitamin K may have a protective role in bone health.

描述（由申请人提供）：维生素 K 在骨骼健康中发挥着新兴作用。然而，人们对维生素 K 代谢知之甚少，特别是在衰老和骨量维持方面。目前对维生素 K 代谢的了解有限，阻碍了制定维生素 K 饮食建议的能力，也阻碍了对目前主要在狭窄年龄组女性中进行的维生素 K 补充剂和骨骼健康近期临床试验结果的解释。拟议的研究将首次评估饮食和非饮食因素的作用，这些因素会影响年轻和老年男性和女性对维生素 K 状态和骨转换对维生素 K 消耗和补充的反应。这项研究还将比较维生素 K 相对于当前维生素 K 状态的吸收效率。男性和女性[21岁以下（21-40岁）和21岁以上（60-80岁）]将参加一项65天的代谢研究，其中有5天的磨合期，随后是30天的膳食维生素K限制期（10μg/天），最后是30天的膳食维生素K补充期（500μg/天）。维生素 K 状态标志物（血浆叶绿醌、尿 Gla、血清 %ucOC 和血浆 PIVKA-II）和骨转换（血清骨钙蛋白和 NTx）的系列测量将提供有关两个年龄组在相同控制饮食条件下对维生素 K 饮食控制的反应的信息。稳定同位素示踪剂（羽衣甘蓝中氘标记的维生素 K）将用于比较维生素 K 耗尽状态（21 天的膳食维生素）期间维生素 K 的吸收情况。 K 消耗）到维生素 K 补充状态（膳食维生素 K 补充 21 天）。由于维生素 K 在富含甘油三酯的脂蛋白中运输，而由于肥胖程度的差异，脂蛋白在个体之间可能有所不同，因此通过 DXA 和血浆脂质（总脂蛋白和个体脂蛋白）测量身体成分将有助于深入了解脂质在维生素 K 吸收和运输中的作用。拟议研究的结果对于解释用于解释维生素 K 的流行病学和临床数据至关重要。 确定维生素 K 对骨骼健康发挥保护作用的最佳摄入量。