Serum 25-hydroxyvitamin D Concentrations (25OHD)
Conditions
Keywords
vitamin D, Serum 25-hydroxyvitamin D, vitamin D2, UV-irradiated yeast, serum 25-hydroxyvitamin D3, serum 25-hydroxyvitamin D2, randomized controlled trial, vitamin D3, bioavailability
Brief summary
Vitamin D3 is synthesized in skin exposed to ultraviolet-B-irradiation of sunlight. However, in Northern Europe, including Finland, exposure to sunlight is limited or non-existent in winter. Between November and March, dietary or supplementary vitamin D intake is essential to maintain adequate serum 25-hydroxyvitamin D (S-25(OH)D) concentrations. There are only a few natural dietary sources of vitamin D. Fish and egg yolks contain significant amounts of vitamin D3 (cholecalciferol), and some wild mushrooms are a source of vitamin D2 (ergocalciferol). Thus, vitamin D fortification of certain foods has been accepted as one strategy to improve vitamin D status of these populations. Vitamin D3 is currently mostly used in fortified products in Europe, although the production of plant-derived vitamin D2 would be more cost-effective. Data on the impact of food-derived vitamin D2 on S-25(OH)D3 are limited. An important consideration is whether food-based sources of vitamin D2 are effective in raising S-25(OH)D or whether they have a negative impact on S-25(OH)D3. The investigators investigated the bioavailability of vitamin D2 from UVB-radiated baking yeast in bread in terms of efficacy of raising total S-25(OH)D) as well its possible effects on S-25(OH)D2, S-25(OH)D3, serum parathyroid hormone (S-PTH) and serum calcium concentrations compared with D2 and D3 supplementation in a randomized placebo-controlled trial in young healthy females during winter in Finland.
Interventions
DIETARY_SUPPLEMENTVitamin D2
Experimental group 2: daily vitamin D2 supplement 25ug/d for 8 weeks
DIETARY_SUPPLEMENTVitamin D3
Experimental group 3: daily vitamin D3 supplement 25ug/d for 8 weeks
OTHERVitamin D2 fortified bread
Experimental group 4: vitamin D2 fortified bread containing 25 µg of vitamin D2/d (bread dose 87g/d) and placebo pill for 8 weeks
Sponsors
University College Cork
Technical University of Denmark
University of Helsinki
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
FEMALE
Age
20 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
* good general health (no continuous medication), * Caucasian origin, * body mass index (BMI) \<30 kg/m2 * age 20-40 years
Exclusion criteria
* diagnosed celiac disease or cereal allergy * a vacation in a sunny place during the study or within the preceding 2 months * regular use of vitamin D supplements \>15 µg/d * pregnancy or breastfeeding during the study
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Serum total 25-hydroxyvitamin D (25(OH)D) | Change from baseline in total 25(OH)D concentration at 4 and 8 weeks | The effect of vitamin D (as form of D3, D2 or D2-fortified bread )supplementation on the serum 25(OH)D concentration |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Serum parathyroid hormone (PTH) concentration | Change from baseline in serum PTH concentration at 4 and 8 weeks | The effect of vitamin D (as form of D3, D2 or D2-fortified bread )supplementation on the serum PTH concentration |
| Serum calcium concentration | Change from baseline in serum calcium concentration at 4 and 8 weeks | The effect of vitamin D (as form of D3, D2 or D2-fortified bread )supplementation on the serum calcium concentration |
| Serum 25-hydroxyvitamin D2 (25(OH)D2) | Change from baseline in 25(OH)D2 concentration at 4 and 8 weeks | The effect of vitamin D (as form of D3, D2 or D2-fortified bread )supplementation on the serum 25(OH)D2 concentration |
| Serum 25-hydroxyvitamin D3 (25(OH)D3) | Change from baseline in 25(OH)D3 concentration at 4 and 8 weeks | The effect of vitamin D (as form of D3, D2 or D2-fortified bread )supplementation on the serum 25(OH)D3 concentration |
Countries
Finland
Outcome results
None listed