D-Light Intervention

NCT02495584 | Completed

• 1 other identifier: 13/NI/0091
• Study Type: interventional
• Target: 52
• Locations: 1 country
• Sites: 1

Brief Summary

Vitamin D insufficiency has become a global concern, with low vitamin D status associated with bone disorders, cardiovascular disease and certain cancers. The United Kingdom (UK) and Ireland are at particular risk of vitamin D deficiency owing to the northerly latitude, increased use of sunscreen, decreased sun exposure and a high level of cloud cover. A recent survey in the UK showed that more than 50% of UK adults have insufficient vitamin D status, with lower levels noted in the winter months. Variations in vitamin D status have been known to vary between summer and winter, owing to our northern latitude (52-55°N) the Ultraviolet (UV)-B intensity in Northern Ireland is inadequate to promote the dermal synthesis of vitamin D during the winter months, causing us to rely on dietary sources. The aim of this intervention is to investigate the main effects of vitamin D3-fortified milk and supplemental vitamin D3 on vitamin D status and functional health outcomes during the winter, and how this intervention will affect subsequent dermal synthesis of vitamin D from UV exposure. Participants will be recruited from the local community. Blood samples will be collected from each participant at two timepoints (September/October and March/April). Pre- and post-intervention blood pressure, grip strength, height, weight, waist and hip circumferences will be measured, in addition participants will undergo a dual energy x-ray absorptiometry (DXA) scan to assess body composition and bone mineral density. Information on general health, lifestyle, physical activity, dietary intake and typical behaviours in the sun will be collected. Following the dietary intervention, a subset of participants will be invited to participate in a follow-up study, examining UV exposure during the summer months, when they will wear a personal wrist dosimeter for 1 month, complete a sun dairy and provide 2 additional blood samples.

Conditions

25-hydroxyvitamin D Concentration (Vitamin D Status)

Keywords

Vitamin D; Fortified milk; Supplementation; UV exposure; Winter; Healthy adults; Body Composition; Muscle function; Blood pressure

Outcome Measures

Primary Outcomes (1)

• Change in vitamin D status (25-hydroxyvitamin D serum concentration)

  Blood analysis

  Baseline + post-intervention (24weeks)

Secondary Outcomes (6)

• Change in body composition

  Baseline + post-intervention (24weeks)

• Change in muscle strength

  Baseline + post-intervention (24weeks)

• Change in inflammation status

  Baseline + post-intervention (24weeks)

• Change in lipid profile

  Baseline + post-intervention (24weeks)

• Change in glucose levels

  Baseline + post-intervention (24weeks)

Other Outcomes (1)

• UV exposure (follow-up)

  8 weeks post-intervention (32-40 weeks)

Study Arms (4)

Treatment 1

EXPERIMENTAL

500ml fortified milk (10µg vitamin D3) +1 supplement capsule (10µg vitamin D3) daily for 24 weeks

Dietary Supplement: Fortified milk (10µg vitamin D3); Dietary Supplement: 10µg vitamin D3 supplement

Treatment 2

EXPERIMENTAL

500ml fortified milk (10µg vitamin D3) +1 supplement capsule (placebo) daily for 24 weeks

Dietary Supplement: Fortified milk (10µg vitamin D3); Dietary Supplement: Placebo supplement

Treatment 3

EXPERIMENTAL

500ml unfortified milk (placebo) +1 supplement capsule (10µg vitamin D3) daily for 24 weeks

Dietary Supplement: Unfortified milk (placebo); Dietary Supplement: 10µg vitamin D3 supplement

Treatment 4

PLACEBO COMPARATOR

500ml unfortified milk (placebo) +1 supplement capsule (placebo) daily for 24 weeks

Dietary Supplement: Unfortified milk (placebo); Dietary Supplement: Placebo supplement

Interventions

Fortified milk (10µg vitamin D3) DIETARY_SUPPLEMENT

Treatment 1; Treatment 2

Unfortified milk (placebo) DIETARY_SUPPLEMENT

Treatment 3; Treatment 4

10µg vitamin D3 supplement DIETARY_SUPPLEMENT

Treatment 1; Treatment 3

Placebo supplement DIETARY_SUPPLEMENT

Treatment 2; Treatment 4

Eligibility Criteria

• Age: 20 Years - 40 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• years old
• Apparently healthy
• Living on the island of Ireland

You may not qualify if:

• Below 20 years and aged 40 years or above
• Not living on the island of Ireland
• Pregnant or lactating women and those planning to become pregnant
• Individuals who have been taking a vitamin D or calcium containing supplement in the previous three months
• Those with food intolerances or allergies that would affect their ability to consume study milk
• Individuals following a diet which excludes milk (e.g. vegans)
• Those with a diagnosed chronic medical condition or on prescribed medication known to effect vitamin D metabolism
• Those who are planning a sun holiday during the winter months (Oct-Mar)
• Adults with learning, or any other difficulties that would prevent them from completing the study protocol

Sponsors & Collaborators

• University of Ulster: lead
• Dairy Council for Northern Ireland: collaborator
• Agri-Food and Biosciences Institute: collaborator
• Center for Nutrition and Health, RIVM (The Netherlands): collaborator

Study Sites (1)

Human Intervention Studies Unit

Coleraine, BT52 1SA, United Kingdom

Location

MeSH Terms

Interventions

Cholecalciferol

Intervention Hierarchy (Ancestors)

Cholestenes; Cholestanes; Steroids; Fused-Ring Compounds; Polycyclic Compounds; Sterols; Vitamin D; Secosteroids; Membrane Lipids; Lipids

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: PREVENTION
• Intervention Model: FACTORIAL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: May 11, 2015
• First Posted: July 13, 2015
• Study Start: September 1, 2014
• Primary Completion: October 1, 2015
• Study Completion: October 1, 2015
• Last Updated: January 15, 2016

Record last verified: 2016-01

Locations

GB (1)