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Evaluating Response to Vitamin D3 and K2 Supplementation in Healthcare Personnel

NCT ID: NCT07199829

Last Updated: 2025-09-30

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

RECRUITING

Clinical Phase

NA

Total Enrollment

96 participants

Study Classification

INTERVENTIONAL

Study Start Date

2025-03-27

Study Completion Date

2026-03-31

Brief Summary

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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.

Detailed Description

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Health promotion efforts for all branches of Service aim to ensure the health and readiness of the Force. This timely, relevant study supports this effort as well as the TriService Nursing Research Program priorities of Fit and Ready Force, Care for the Caregiver, and Translate Research into Practice. In 2023, the Defense Health Agency unveiled its strategic plan through 2028 which included these two priorities, 1) 'achieving new levels of excellence by fully leveraging emerging scientific and technological advancements to optimize the health and care experience of our beneficiaries', and 2) 'creating a workplace where people are the primary focus, and the principles of high reliability nurture and energize each individual'. The previous nutrigenomics work by this research team, the expertise and enthusiasm of our new members, and the choice of diverse cohorts for this study, presents an exciting and potentially impactful extension of nutrigenomics with metagenomics of the gut microbiome to provide insight into complex nutrient pathways and specifically, the response of the gut microbial community to select micronutrients. Vitamin D and vitamin K2 are vital micronutrients that support immune, bone, gut, and cardiometabolic health with insufficiencies contributing to musculoskeletal injuries (MSKi), metabolic syndrome, cardiovascular disease, and gut dysbiosis. This Follow-On research application advances the science linking vitamin D, lifestyle behaviors, and chronic disease prevention in healthy adults by probing unexplored areas such as a key symbiotic nutrient, vitamin K2, with vitamin D3, next generation sequencing (NGS) of polymorphisms involved in vitamin metabolism pathways as well as metagenomics to assess the response of the gut microbial community to dietary and supplemental nutrients. The Specific Aims and research questions for our study include:

Specific Aim 1. Evaluate effect of vitamin D3 and K2 dietary intake and supplementation groups vs placebo group on the gut microbiome; Research Question (RQ)1.a. Will gut microbiome composition, diversity, and richness respond differently to each treatment group - vitamin D3, vitamin K2, D3+K2 versus the control group? RQ1.b. What effect will vitamin D3 and/or K2 metabolism pathway single nucleotide polymorphisms (SNPs) have on gut microbiome response?

Specific Aim 2. Assess response to vitamin supplementation with serum 25-hydroxyvitamin D \[25(OH)D\] and osteocalcin levels pre and post supplement; RQ2. Will selected doses, based on clinical experience and published data, achieve designated endpoints for sufficiency; serum 25(OH)D greater than 30 ng/mL and undercarboxylated osteocalcin (ucOC) within normal limits?

Specific Aim 3. Assess the influence of vitamin D and K metabolism pathway SNPs on serum 25(OH)D and osteocalcin to determine vitamin D3, K2, and D3 + K2 supplementation efficacy; RQ3. To what extent does the presence of vitamin D and/or K metabolism pathway SNPs affect supplement efficacy when comparing treatment vs control group response measured by serum biomarkers?

Specific Aim 4. Explore relationships between diet/Dietary Inflammatory Index (DII), lifestyle behaviors (steps and sleep), body composition, metabolic and inflammatory biomarkers, SNPs, and the gut microbiome from Baseline to 3 months; RQ4.a. What factors need consideration when exploring genetic and non-genetic contributions to the gut microbiome in the treatment vs control group? RQ4.b. What role do age, gender, body mass index, inflammation status, and lipid profile play in the gut microbiome composition?

Hypothesis 1: Genotypic alterations in vitamin D3 and/or K2 metabolism pathways will influence gut microbiome composition in response to supplementation.

Hypothesis 2: Genotypic alterations in vitamin D3 and/or K2 metabolism pathways will influence serum response to supplementation.

Conditions

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Hypovitaminosis D Hypovitaminosis

Keywords

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Hypovitaminosis D Hypovitaminosis K Gut microbiome

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Double-blind randomized controlled trial (RCT) with 4 arms.
Primary Study Purpose

TREATMENT

Blinding Strategy

QUADRUPLE

Participants Caregivers Investigators Outcome Assessors

Study Groups

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Vitamin Arm 1

Vitamin D3 125 mcg taken orally once daily for 90 days

Group Type ACTIVE_COMPARATOR

Vitamin Arm 1

Intervention Type DIETARY_SUPPLEMENT

Subject receives dietary supplement for 90 days

Vitamin Arm 2

Vitamin K2 180 mcg taken orally once daily for 90 days

Group Type ACTIVE_COMPARATOR

Vitamin Arm 2

Intervention Type DIETARY_SUPPLEMENT

Subject receives dietary supplement for 90 days

Vitamin Arm 3

Vitamin D3 125 mcg combined with vitamin K2 180 mcg taken orally once daily for 90 days

Group Type ACTIVE_COMPARATOR

Vitamin Arm 3

Intervention Type DIETARY_SUPPLEMENT

Subject receives dietary supplement for 90 days

Placebo Arm

Inert capsule taken orally once daily for 90 days

Group Type PLACEBO_COMPARATOR

Placebo

Intervention Type OTHER

Subject receives placebo for 90 days

Interventions

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Vitamin Arm 1

Subject receives dietary supplement for 90 days

Intervention Type DIETARY_SUPPLEMENT

Vitamin Arm 2

Subject receives dietary supplement for 90 days

Intervention Type DIETARY_SUPPLEMENT

Vitamin Arm 3

Subject receives dietary supplement for 90 days

Intervention Type DIETARY_SUPPLEMENT

Placebo

Subject receives placebo for 90 days

Intervention Type OTHER

Eligibility Criteria

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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)
Minimum Eligible Age

18 Years

Maximum Eligible Age

69 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Madigan Army Medical Center

FED

Sponsor Role lead

Responsible Party

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Mary S McCarthy

Senior Nurse Scientist

Responsibility Role PRINCIPAL_INVESTIGATOR

Principal Investigators

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Mary S McCarthy, PhD

Role: PRINCIPAL_INVESTIGATOR

Madigan AMC

Locations

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Madigan Army Medical Center

Tacoma, Washington, United States

Site Status RECRUITING

Countries

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United States

Central Contacts

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Mary S McCarthy, PhD

Role: CONTACT

Phone: 253-968-3695

Email: [email protected]

Hyojin C Yi, BSN

Role: CONTACT

Phone: 253-968-2898

Email: [email protected]

Facility Contacts

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Mary S McCarthy, PhD

Role: primary

Hyojin C Yi, BSN

Role: backup

References

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Akimbekov NS, Digel I, Sherelkhan DK, Lutfor AB, Razzaque MS. Vitamin D and the Host-Gut Microbiome: A Brief Overview. Acta Histochem Cytochem. 2020 Jun 26;53(3):33-42. doi: 10.1267/ahc.20011. Epub 2020 Jun 16.

Reference Type BACKGROUND
PMID: 32624628 (View on PubMed)

Levin GP, Robinson-Cohen C, de Boer IH, Houston DK, Lohman K, Liu Y, Kritchevsky SB, Cauley JA, Tanaka T, Ferrucci L, Bandinelli S, Patel KV, Hagstrom E, Michaelsson K, Melhus H, Wang T, Wolf M, Psaty BM, Siscovick D, Kestenbaum B. Genetic variants and associations of 25-hydroxyvitamin D concentrations with major clinical outcomes. JAMA. 2012 Nov 14;308(18):1898-905. doi: 10.1001/jama.2012.17304.

Reference Type BACKGROUND
PMID: 23150009 (View on PubMed)

Ammar M, Heni S, Tira MS, Khalij Y, Hamdouni H, Amor D, Ksibi S, Omezzine A, Bouslama A. Variability in response to vitamin D supplementation according to vitamin D metabolism related gene polymorphisms in healthy adults. Eur J Clin Nutr. 2023 Feb;77(2):189-194. doi: 10.1038/s41430-022-01218-y. Epub 2022 Sep 27.

Reference Type BACKGROUND
PMID: 36167979 (View on PubMed)

Other Identifiers

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11207-N24-B11

Identifier Type: OTHER_GRANT

Identifier Source: secondary_id

225015

Identifier Type: -

Identifier Source: org_study_id