Evaluating Response to Vitamin D3 and K2 Supplementation in Healthcare Personnel

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.

NCT Number	NCT07199829
Lead Sponsor	Madigan Army Medical Center
Conditions	Hypovitaminosis D, Hypovitaminosis
Enrollment	96 participants
Start Date	2025-03-27
Primary Completion	2026-03 (estimated)
Study Completion	2026-03 (estimated)
Updated on ClinicalTrials.gov	2025-09-30