Determinants of Vitamin K Metabolism
| Status: | Completed |
|---|---|
| Conditions: | Healthy Studies, Osteoporosis |
| Therapuetic Areas: | Rheumatology, Other |
| Healthy: | No |
| Age Range: | 18 - 90 |
| Updated: | 11/29/2017 |
| Start Date: | May 2006 |
| End Date: | July 2009 |
Dietary and Non-dietary Components of Vitamin K Metabolism
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.
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.
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 Dual Energy X-Ray Absorptiometry (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.
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 Dual Energy X-Ray Absorptiometry (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.
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
We found this trial at
1
site
711 Washington Street
Boston, Massachusetts 02111
Boston, Massachusetts 02111
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