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在骨骼健康中的作用正在显现。然而，人们对维生素K的代谢知之甚少，特别是关于衰老和骨量的维持。对维生素K代谢的这种有限的了解目前阻碍了建立维生素K饮食建议的能力，并解释了最近关于维生素K补充剂和骨骼健康的临床试验的结果，目前主要在狭窄年龄组的妇女中进行。这项拟议的研究将首次评估饮食和非饮食因素的作用，这些因素影响年轻和老年男性和女性对维生素K状况和骨骼周转指标对维生素K耗竭和再利用的反应。这项研究还将比较维生素K的吸收效率，相对于目前的维生素K状况。男性和女性[21名年轻人(21-40岁)和21名老年人(60-80岁)]将参加一项为期65天的代谢研究，其中包括5天的磨合期，然后是30天的膳食维生素K限制期(10亩/克/天)，最后是30天的膳食维生素K补充期(500亩/天)。连续测量维生素K状况的标志物(血浆叶醌、尿GLA、血清%ucOC和血浆PIVKA-II)和骨转换(血清骨钙素和NTX)将提供两个年龄组在相同控制饮食条件下对饮食操作维生素K的反应的信息。一种稳定的同位素示踪剂(羽衣甘蓝中的氚标记的维生素K)将被用来比较维生素K耗竭状态(饮食中维生素K的第21天)对维生素K的吸收 K耗竭)转变为维生素K充足状态(膳食维生素K耗竭21d)。由于维生素K是通过富含甘油三酯的脂蛋白运输的，由于肥胖程度的不同，不同个体的脂蛋白可能有所不同，因此通过DXA和血浆脂类(总和个别脂蛋白)测量身体成分将有助于深入了解脂类在维生素K吸收和运输中的作用。这项拟议的研究结果对于解释流行病学和临床数据至关重要，这些数据用于确定维生素K在骨骼健康中可能具有保护作用的最佳摄入量。