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Study identifier: NCT07199829 Synced from ClinicalTrials.gov · July 28, 2026
● Recruiting

Evaluating Response to Vitamin D3 and K2 Supplementation in Healthcare Personnel

Condition: Hypovitaminosis D · Hypovitaminosis  ·  Sponsor: Madigan Army Medical Center

PhaseNA
Planned participants96
Who can joinAll sexes, 18 Years to 69 Years
Healthy volunteersYes

About this study

The main purpose of this research study is to learn about the effects of supplemental vitamin D3 and vitamin K2 on blood levels and the gut microbial community, called the gut microbiome. There are many influences on blood levels of vitamin D and K to include your dietary intake, lifestyle behaviors (physical activity, sleep), genetic alterations in metabolism of these vitamins, and the gut microbial abundance and diversity. You will be asked to take one capsule containing vitamin D3 (125 mcg), vitamin K2 (180 mcg), a combination of vitamins D3 and K2 (same doses as previous), or a placebo powder for 90 days. You will also be asked to complete questionnaires, undergo body composition and blood pressure measurements, provide blood samples and a stool swab, all on 2 occasions about 3 - 4 months apart. By conducting this study, we aim to identify the frequency of common genetic alterations in vitamins D and K metabolism and establish the impact on the gut microbiome for the first time. Your participation in this study will last about 4 - 6 months and include up to 3 visits.

This description comes directly from the study's public registry record.

Talk to the study team

Mary S McCarthy, PhD  ·  253-968-3695  ·  mary.s.mccarthy1.civ@health.mil

Hyojin C Yi, BSN  ·  253-968-2898  ·  hyojin.c.yi.ctr@health.mil

Always discuss trial participation with your own doctor first.

Locations (1)

Madigan Army Medical CenterTacoma, Washington, United StatesRecruiting

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Source record: clinicaltrials.gov/study/NCT07199829