Determinants of Vitamin K Metabolism

This study has been completed.
Information provided by (Responsible Party):
Sarah Booth, Tufts University Identifier:
First received: June 12, 2006
Last updated: December 17, 2013
Last verified: December 2013
The purpose of this study is to learn how the body responds to different amounts of vitamin K in the diet in order to understand the roles that vitamin K may have in the body. We also need to determine if older adults need more or less vitamin K in their diet compared to younger adults in order to maintain normal body stores of vitamin K.

Condition Intervention
Drug: Vitamin K

Study Type: Interventional
Study Design: Allocation: Non-Randomized
Endpoint Classification: Bio-availability Study
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Basic Science
Official Title: Dietary and Non-dietary Components of Vitamin K Metabolism

Resource links provided by NLM:

Further study details as provided by Tufts University:

Primary Outcome Measures:
  • Urinary excretion of VK metabolites at VK depletion and repletion [ Time Frame: 2 months ] [ Designated as safety issue: No ]
  • Bone turnover markers at VK depletion and repletion [ Time Frame: 2 months ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Plasma triglyceride levels at VK depletion and repletion [ Time Frame: 2 months ] [ Designated as safety issue: No ]
  • Glucose metabolism measures at VK depletion and repletion [ Time Frame: 2 months ] [ Designated as safety issue: No ]
  • Mood assessment at VK depletion and repletion [ Time Frame: 2 months ] [ Designated as safety issue: No ]

Enrollment: 59
Study Start Date: May 2006
Study Completion Date: July 2009
Primary Completion Date: July 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Diet
Diet low vitamin K, diet high vitamin K
Drug: Vitamin K
phylloquinone (vitamin K1) 500 mcg daily in third month

Detailed Description:
Vitamin K has a role in bone health, but little is known about vitamin K metabolism in aging and in maintenance of bone mass. The limited understanding of vitamin K metabolism impedes the establishment of dietary recommendations for vitamin K, and the interpretation of results from clinical trials on vitamin K supplementation and bone health of women in a narrow age group. This study is the first to assess the role of dietary and other factors that influence the response to vitamin K status and bone turnover to vitamin K depletion and repletion in adults. This study also compares the absorption efficiency and body retention of vitamin K relative to current vitamin K status. Men and women [21 younger (18-40y) and 21 older (55+y)] will participate in a 62-d metabolic study, with a 5d run-in period, followed by a 28d dietary vitamin K restriction period (10 ug/d), and ending with a 28d dietary vitamin K supplementation period (500 ug/d). Coagulation times will be monitored during the dietary restriction period. Serial measurements of vitamin K status markers and of bone turnover markers will show the response of vitamin K to dietary manipulation for both age groups under identically controlled dietary conditions. Deuterium-labeled vitamin K in collards will be used to compare the absorption of vitamin K during a vitamin K-deplete state to that of a vitamin K-replete state. Vitamin K is transported in triglyceride-rich lipoproteins, which may vary among individuals due to differences in adiposity and lipid homeostasis. Therefore, measurement of body composition by DXA and plasma lipids will provide insight into the role of lipids in absorption and transport of vitamin K. The findings of this study are critical for the interpretation of the epidemiologic and clinical data used to determine the protective role vitamin K may have in chronic disease prevention.

Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

Exclusion Criteria:

  • kidney, GI, or liver disease requiring treatment
  • prescribed osteoporosis medications in the previous 3 months
  • use of acid reducers more than twice per week
  • blood clotting disorder and/or abnormal clotting time
  • warfarin or anticoagulant use in the previous 12 months
  • diabetes
  • smoking
  • hormone therapy in the previous 3 months
  • oral contraceptive use in the previous 3 months; pregnancy
  • strict vegetarian diet
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00336232

United States, Massachusetts
Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University
Boston, Massachusetts, United States, 02111
Sponsors and Collaborators
Tufts University
Principal Investigator: Sarah L Booth, PhD Tufts Medical Center
  More Information

Additional Information:
Responsible Party: Sarah Booth, Senior Scientist, Tufts University Identifier: NCT00336232     History of Changes
Other Study ID Numbers: R01DK069341 
Study First Received: June 12, 2006
Last Updated: December 17, 2013
Health Authority: United States: Federal Government

Keywords provided by Tufts University:
Vitamin K metabolism
Bone health

Additional relevant MeSH terms:
Vitamin K
Antifibrinolytic Agents
Fibrin Modulating Agents
Growth Substances
Hematologic Agents
Molecular Mechanisms of Pharmacological Action
Pharmacologic Actions
Physiological Effects of Drugs
Therapeutic Uses processed this record on May 04, 2016