Dietary Supplementation With 25-hydroxyvitamin D3 in Older Adults

Study Overview
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Brief Summary
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The purpose of this study is to investigate whether a supplement of 25-hydroxyvitamin D is five-times more potent in raising vitamin D status (as reflected by serum 25(OH)D) compared to an equivalent amount of vitamin D3 in older adults. It will entail a 10 week supplementation study during winter months.

Detailed Description
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The UK (McCance & Widdowson) food composition tables suggests that 25-hydroxyvitamin D (which is present in some foods, albeit at very low concentrations, but which is also commercially available) may possess up to 5-times the activity of native vitamin D3 in food. Thus, in theory, each micogram of 25-hydroxyvitamin D consumed in the diet could boost vitamin D status up to five times most effectively compared to each microgram of native vitamin D in food. It is worth noting, however, that estimates of potency range from 2 to 5, depending on approach used, and that the real potency needs to be confirmed in a human study. This study aims to examine the biological activity of 25-hydroxyvitamin D (i.e., its potency relative to vitamin D3) as well as its effect on selected functional markers in a randomised, double-blind, human intervention trial in older adults.

Official Title
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Comparison of the Bioefficacy of Oral 25-hydroxyvitamin D3 and Vitamin D3 Supplements on Vitamin D Status in Older Adults

Conditions
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Vitamin D Status as Reflected by Serum 25-hydroxyvitamin D

Intervention / Treatment
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* Dietary Supplement: vitamin D3
* Dietary Supplement: 25-hydroxyvitamin D3
* Dietary Supplement: 25-hydroxyvitamin D (20 microgram/day)
* Dietary Supplement: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Subjects will be eligible if they are 45+ years of age Body Mass Index (BMI) 19-30 Exclusion Criteria: have hypercalcaemia chronic illness renal or liver disorders taking medications that might interact with vitamin D or metabolite drank more than > 21 standards (male)/ 14 standards (female) of alcohol per week planning to change smoking habits

Ages Eligible for Study
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Minimum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Vitamin D3 (20 microgram/day)<br> | Dietary Supplement: vitamin D3<br>* 20 micrograms per day for 10 weeks<br>|
| Active Comparator: 25-hydroxyvitamin D (7 microgram/day)<br> | Dietary Supplement: 25-hydroxyvitamin D3<br>* 7 microgram/day for 10 weeks<br>|
| Active Comparator: 25-hydroxyvitamin D3 (20 micogram/day)<br> | Dietary Supplement: 25-hydroxyvitamin D (20 microgram/day)<br>* 20 microgramday for 10 weeks<br>|
| Placebo Comparator: Placebo<br> | Dietary Supplement: Placebo<br>* 0 ug vitamin D3/25-hydroxyvitamin D3/day for 10 weeks<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| serum 25-hydroxyvitamin D concentration |  | 10 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| serum parathyroid hormone |  | 10 weeks | 
| blood pressure |  | 10 weeks | 
| biochemical markers of bone turnover |  | 10 weeks | 
| serum calcium adjusted for albumin |  | 10 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Vitamin D status, 25-hydroxyvitamin D, Vitamin D3, RCT, Bio-efficacy