Vitamin D and Immunity: Photosynthesis Versus Supplementation
- Conditions
- Vitamin D Deficiency
- Interventions
- Radiation: UVR (Solar simulated radiation)Dietary Supplement: Vitamin D
- Registration Number
- NCT03609970
- Lead Sponsor
- Guy's and St Thomas' NHS Foundation Trust
- Brief Summary
The optimal way to restore serum 25-hydroxyvitamin D sufficiency is currently debatable. UV irradiation through sunshine exposure promotes endogenous vitamin D synthesis, although this can also be associated with a risk of UVR-induced skin cancer. Dietary supplements represent an alternative, which are increasingly being used in clinical trials to correct deficiency. However, it is unclear whether sunshine exposure and vitamin D supplementation induce comparable changes in immune function, or whether additional UVR-induced molecules may be responsible for proposed health benefits. Several studies report an inverse correlation between exposure to UVR and immune-mediated diseases, further supporting the theory that UVR may also be protective through non vitamin-D mediated pathways. So far it has been difficult to distinguish between immune-regulation by vitamin D and other mediators induced by UVR as the downstream effects are similar. A direct comparison of the biological effects of vitamin D obtained by UVR versus supplementation has never been made. This study aims to elucidate the differences in vitamin D generated by UVR exposure versus supplementation by comparing immunological endpoints
- Detailed Description
Not available
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 36
- Age: 18-40
- Fitzpatrick skin type I/II
- Healthy
- Serum 25(OH)D3 <50nmol/L
Serum 25(OH)D3 >50nmol/L
- Pregnant or nursing women
- Women of child bearing age not using adequate contraception
- Are taking photosensitizing medication (i.e. causes you to be more sensitive to sunlight)
- Have had a history of skin disorders, sensitive skin, sensitivity to sunlight or skin cancer
- Have previously had an organ transplant
- Have partaken in a clinical study within the last 14 days
- Have had recent exposure to sunbeds (last 4 months) or holiday sun (including skiing)
- Are currently or have taken vitamin D supplements in the last 4 months Are asthmatic or suffer from any allergies
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Arm && Interventions
Group Intervention Description UVR (Solar simulated radiation) UVR (Solar simulated radiation) Twice weekly 1.25 SED (sub-erythemal) (4 weeks) Vitamin D3 supplementation Vitamin D 4X 1000IU cholecalciferol tablets daily (28 days)
- Primary Outcome Measures
Name Time Method Vitamin D status of healthy participants treated with oral vitamin D (cholecalciferol) or UVR (SSR) exposures and control (untreated) 3 years Measure 25(OH)D3nmol/L via LC-MS/MS
- Secondary Outcome Measures
Name Time Method Gene expression in peripheral blood myeloid and plasmacytoid dendritic cells 3 years Differentially regulated genes in myeloid and plasmacytoid dendritic cells in participants after vitamin D repletion via supplementation and UVR (SSR) exposure via Microarray.
Impact upon the frequency and phenotype of peripheral blood dendritic cells 3 years Frequency of peripheral blood dendritic cells (myeloid and plasmacytoid) in individuals with insufficient vitamin D levels and following vitamin D repletion via supplementation or UVR (SSR) exposures. Assessment of markers of maturation/tolerogenicity (MFI and frequency expressing) on myeloid and plasmacytoid dendritic cells direct ex vivo and after stimulation in vitro in participants when vitamin D insufficient and sufficient.
Changes to peripheral blood cell frequency 3 years Frequency of major peripheral immune cells (e.g. CD3+ T cells, CD3+ CD4+ T cells, CD3+ CD8+ T cells, CD19+ B cells, Natural Killer Cells, Classical, Non-classical and Intermediate Monocytes) in participants when vitamin D insufficient and sufficient. Via flow cytometry.