NCT07349290

Brief Summary

Vitamin D is essential for healthy bones, muscles, and immune function. It comes from food, supplements, and sunlight. There are two main forms; vitamin D2, found mainly in plant foods, and vitamin D3, which comes from animal foods and is more effective at increasing vitamin D levels in the body. In the UK, sunlight is often too weak especially in winter for the body to make enough vitamin D, so people rely mainly on dietary sources and supplements. Despite this, many people in the UK have low vitamin D levels, and teenagers are particularly at risk due to increased needs during growth, with around one in five adolescents having low vitamin D levels. Poor intake of vitamin D-rich foods, low supplement use, and inconsistent food fortification contribute to this problem. This study aims to assess whether a family-based household diet using natural and fortified vitamin D foods during winter can improve vitamin D levels in adolescents.

Trial Health

75
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
160

participants targeted

Target at P75+ for not_applicable

Timeline
11mo left

Started Feb 2026

Geographic Reach
1 country

1 active site

Status
enrolling by invitation

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Progress21%
Feb 2026Apr 2027

First Submitted

Initial submission to the registry

January 8, 2026

Completed
8 days until next milestone

First Posted

Study publicly available on registry

January 16, 2026

Completed
27 days until next milestone

Study Start

First participant enrolled

February 12, 2026

Completed
1.1 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

April 1, 2027

Expected
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

April 1, 2027

Last Updated

May 6, 2026

Status Verified

January 1, 2026

Enrollment Period

1.1 years

First QC Date

January 8, 2026

Last Update Submit

May 5, 2026

Conditions

Vitamin D FortificationVitamin D StatusVitamin D Biofortification

Keywords

Vitamin DBiofortificationFortificationHouseholdVitamin D Status

Outcome Measures

Primary Outcomes (1)

  • Vitamin D status

    Measured by LC-MS/MS for 25(OH)D concentrations (µmol/L)

    From enrolment to the end of treatment at 4 weeks, comparison between treatments

Secondary Outcomes (4)

  • Vitamin D intake

    From enrolment to the end of treatment at 4 weeks, comparison between treatments

  • Acceptability of food baskets

    From enrolment to the end of treatment at 4 weeks, comparison between treatments

  • Knowledge of vitamin D

    From enrolment to the end of treatment at 4 weeks, comparison between treatments

  • Perceptions and habits of vitamin D

    From enrolment to the end of treatment at 4 weeks, comparison between treatments

Study Arms (2)

Vitamin D (bio)fortified foods

EXPERIMENTAL
Other: Vitamin D (bio)fortified food basket

Control foods

EXPERIMENTAL
Other: Control food basket

Interventions

Control food basketOTHER

Basket of control foods provided to a household for consumption

Control foods
Vitamin D (bio)fortified food basketOTHER

Basket of vitamin D (bio)fortified foods provided to a household for consumption

Vitamin D (bio)fortified foods

Eligibility Criteria

Age4 Years+
Sexall
Healthy VolunteersYes
Age GroupsChild (0-17), Adult (18-64), Older Adult (65+)

You may qualify if:

  • Households with at least one adult member (≥18 years) and at least one adolescent member (11-17 years).
  • Participants willing to consume the majority of study foods provided
  • Participants willing to provide a total of two blood samples (maximum 25ml at each timepoint).

You may not qualify if:

  • Any food allergies or intolerances, including anaphylaxis allergies
  • Individuals taking/unwilling to stop taking high dose vitamin D supplements (1000 IU) for a washout period (4 weeks before) and for the duration of the study period
  • Individuals with conditions causing malabsorption, e.g. coeliac disease

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Ulster University, Human Intervention Studies Unit, Coleraine, Co. Londonderry

Coleraine, BT52 1SA, United Kingdom

Location

MeSH Terms

Interventions

Vitamin D

Intervention Hierarchy (Ancestors)

SecosteroidsSteroidsFused-Ring CompoundsPolycyclic Compounds

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
NONE
Purpose
OTHER
Intervention Model
PARALLEL
Model Details: Randomised unblinded parallel household trial
Sponsor Type
OTHER
Responsible Party
SPONSOR

Study Record Dates

First Submitted

January 8, 2026

First Posted

January 16, 2026

Study Start

February 12, 2026

Primary Completion (Estimated)

April 1, 2027

Study Completion (Estimated)

April 1, 2027

Last Updated

May 6, 2026

Record last verified: 2026-01

Data Sharing

IPD Sharing
Will not share

Locations

GB(1)