Evaluating Response to Vitamin D3 and K2 Supplementation in Healthcare Personnel

NCT07199829 | Recruiting

• 2 other identifiers: 22501511207-N24-B11
• Study Type: interventional
• Target: 96
• Locations: 1 country
• Sites: 1

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.

Conditions

Hypovitaminosis D; Hypovitaminosis

Keywords

Hypovitaminosis D; Hypovitaminosis K; Gut microbiome

Outcome Measures

Primary Outcomes (3)

• Gut microbiome composition

  Evaluate effect of vitamin D3 and K2 dietary intake, and assigned vitamin supplementation group versus placebo group, on the gut microbiome composition

  90 days

• Gut microbiome richness

  Will use Operational Taxonomic Units, Simpson Index and /or Chao1 index to evaluate gut microbiome richness before and after vitamin supplementation vs placebo

  90 days

• Gut microbiome diversity

  Will use Operational Taxonomic Units, Simpson Index and /or Chao1 index to evaluate gut microbiome diversity before and after vitamin supplementation vs placebo

  90 days

Secondary Outcomes (4)

• Serum 25OHD

  90 days

• Serum Osteocalcin level

  90 days

• Vitamin D3 and K2 metabolic pathway variants on supplementation efficacy

  90 days

• Genetic and non-genetic factor contributions to gut microbiome composition

  90 days

Study Arms (4)

Vitamin Arm 1

ACTIVE COMPARATOR

Vitamin D3 125 mcg taken orally once daily for 90 days

Dietary Supplement: Vitamin Arm 1

Vitamin Arm 2

ACTIVE COMPARATOR

Vitamin K2 180 mcg taken orally once daily for 90 days

Dietary Supplement: Vitamin Arm 2

Vitamin Arm 3

ACTIVE COMPARATOR

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

Dietary Supplement: Vitamin Arm 3

Placebo Arm

PLACEBO COMPARATOR

Inert capsule taken orally once daily for 90 days

Other: Placebo

Interventions

Vitamin Arm 1 DIETARY_SUPPLEMENT

Subject receives dietary supplement for 90 days

Vitamin Arm 1

Vitamin Arm 2 DIETARY_SUPPLEMENT

Subject receives dietary supplement for 90 days

Vitamin Arm 2

Vitamin Arm 3 DIETARY_SUPPLEMENT

Subject receives dietary supplement for 90 days

Vitamin Arm 3

Placebo OTHER

Subject receives placebo for 90 days

Placebo Arm

Eligibility Criteria

• Age: 18 Years - 69 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• able to read and understand English
• 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

You may not qualify if:

• 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)

Sponsors & Collaborators

• Madigan Army Medical Center: lead

Study Sites (1)

Madigan Army Medical Center

Tacoma, Washington, 98431, United States

RECRUITING

Related Publications (3)

• 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.

  PMID: 32624628 BACKGROUND

• 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.

  PMID: 23150009 BACKGROUND

• 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.

  PMID: 36167979 BACKGROUND

MeSH Terms

Conditions

Vitamin D Deficiency; Avitaminosis

Condition Hierarchy (Ancestors)

Deficiency Diseases; Malnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases

Study Officials

• Mary S McCarthy, PhD

  Madigan AMC

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Mary S McCarthy, PhD

CONTACT

253-968-3695; mary.s.mccarthy1.civ@health.mil

Hyojin C Yi, BSN

CONTACT

253-968-2898; hyojin.c.yi.ctr@health.mil

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: FED
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Senior Nurse Scientist

Model Details: Double-blind randomized controlled trial (RCT) with 4 arms.

Study Record Dates

• First Submitted: February 6, 2025
• First Posted: September 30, 2025
• Study Start: March 27, 2025
• Primary Completion: March 1, 2026
• Study Completion: March 1, 2026
• Last Updated: September 30, 2025

Record last verified: 2025-09

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF
• Time Frame: Supporting information will be available upon request after completion of protocol, for the following 2 years.
• Access Criteria: Contact principal investigator at mary.s.mccarthy1.civ@health.mil

Locations

US (1)