NCT07199829 Evaluating Response to Vitamin D3 and K2 Supplementation in Healthcare Personnel
| NCT ID | NCT07199829 |
| Status | Recruiting |
| Phase | — |
| Sponsor | Madigan Army Medical Center |
| Condition | Hypovitaminosis D |
| Study Type | INTERVENTIONAL |
| Enrollment | 96 participants |
| Start Date | 2025-03-27 |
| Primary Completion | 2026-03 |
Eligibility & Interventions
Eligibility Fast-Check
Enter your details for a quick preliminary check. This does not replace medical advice.
What to Expect as a Participant
You will actively receive the study intervention — which may be a drug, biologic, device, or procedure.
This trial targets 96 participants in total. It began in 2025-03-27 with a primary completion date of 2026-03.
⚠ This information is for research awareness only. Always consult your physician before joining any clinical trial. Participation is voluntary and you may withdraw at any time.
Brief Summary
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.
Eligibility Criteria
Inclusion Criteria: * able to read and understand English * 25 OHD serum level equal to or less than 30 ng/mL * willing to discontinue vitamin D3 and/or K2 supplements for 4.5 months * military beneficiary (Active Duty, Retired, Dependent) * remaining employed at workplace for 6 months Exclusion Criteria: * Diagnosed medical condition that prevents nutrient absorption from food (e.g. Inflammatory Bowel Disease, Celiac Disease, post-Roux-en-Y/Gastric sleeve surgery) * Pregnant or breastfeeding * Current antibiotic use or within past 3 months * Current anticoagulant use or within past 3 months * Current weight loss or fat malabsorption medication use (e.g. Glucagon-Like Peptide 1 agonists, Orlistat) * Allergies or sensitivities to methylcellulose, vitamin D (D3, D2), or vitamin K (K2, Menaquinone-4, Menaquinone-7)
Contact & Investigator
Mary S McCarthy, PhD
PRINCIPAL INVESTIGATOR
Madigan AMC
Frequently Asked Questions
Who can join the NCT07199829 clinical trial?
This trial is open to participants of all sexes, aged 18 Years or older, up to 69 Years, studying Hypovitaminosis D. Full inclusion and exclusion criteria are listed in the Eligibility Criteria section. Always confirm your eligibility with the research team before applying.
Is NCT07199829 currently recruiting?
Yes, NCT07199829 is actively recruiting participants. Contact the research team at mary.s.mccarthy1.civ@health.mil for enrollment information.
Where is the NCT07199829 trial being conducted?
This trial is being conducted at Tacoma, United States.
Who is sponsoring the NCT07199829 clinical trial?
NCT07199829 is sponsored by Madigan Army Medical Center. The principal investigator is Mary S McCarthy, PhD at Madigan AMC. The trial plans to enroll 96 participants.