Effects of Vitamin D Fortification on Vitamin D Metabolite Profiles and Status in Vitamin D Insufficient Individuals

Study Overview
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Brief Summary
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This is a cross-sectional study designed to compare plasma/serum and urine vitamin D metabolite profiles of vitamin D sufficient and insufficient individuals. There are two phases of this study. Phase 1 - Consented study participants will attend a screening visit and provide a fasting blood and urine sample. Those individuals who are vitamin D insufficient based on serum 25(OH)D concentrations will be invited to participate in Phase II Phase II - is a double-blind, randomized, control study designed to examine vitamin D status in vitamin D insufficient individuals consuming a water-soluble form of vitamin D3. Eligible participants will be asked to consume one of three beverages: i) rooibos iced-tea (control); ii) rooibos iced-tea fortified with 1000 IU of water-soluble vitamin D3; or iii) rooibos iced-tea fortified with 1000 IU of water-soluble vitamin D3 and 360 mg calcium at 240 mL of iced-tea consumed daily for 6 weeks. Participants will attend 6 weekly visits following baseline and provide a fasting blood sample for assessment of serum 25(OH)D concentrations. Objectives: 1) To investigate plasma/serum and urine vitamin D metabolite profiles in vitamin D sufficient and insufficient individuals; and 2) To determine the effects of vitamin D3 fortification on serum 25-dihydroxy-vitamin D [25(OH)D] concentrations, markers of vitamin D and calcium metabolism, and vitamin D metabolite profile in plasma/serum and urine of vitamin D insufficient individuals.

Detailed Description
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Health individuals from the general public will be recruited into this cross-sectional study designed to compare plasma/serum and urine vitamin D metabolite profiles of those identified as vitamin D sufficient and insufficient individuals. There are two objectives: Objective 1: To investigate plasma/serum and urine vitamin D metabolite profiles in vitamin D sufficient and insufficient individuals; N=20 and will consist of 10 individuals identified as vitamin D insufficient and 10 individuals identified as vitamin D deficient individuals. Objective 2: To determine the effects of vitamin D3 fortification on serum 25-dihydroxy-vitamin D [25(OH)D] concentrations, markers of vitamin D and calcium metabolism, and vitamin D metabolite profile in plasma/serum and urine of vitamin D insufficient individuals. N=45. To achieve the objectives, the study will be conducted in two phases: Phase 1 - Healthy males or females, ≥19 and ≤50 years of age, will be recruited from the general public. Consented study participants will provide a fasting blood and urine sample for the purpose of determination of vitamin D status (insufficient vs. deficient) based on serum 25(OH)D concentrations. Forty-five (45) individuals identified as vitamin D insufficient (having a serum 25(OH)D concentration ≥30 and ≤75 nmol/L) will proceed to phase II. A N=20 (10 vitamin D insufficient and 10 vitamin D deficient) will also be identified to satisfy objective 1. Phase II - is a double-blind, randomized, control study designed to examine vitamin D status in vitamin D insufficient individuals consuming a water-soluble form of vitamin D3. Eligible participants will randomized to consume one of three beverages: i) rooibos iced-tea (control); ii) rooibos iced-tea fortified with 1000 IU of water-soluble vitamin D3; or iii) rooibos iced-tea fortified with 1000 IU of water-soluble vitamin D3 and 360 mg calcium at 240 mL of iced-tea consumed daily for 6 weeks. Both researchers and participants will be blinded to the beverage group assigned to each participant. Participants will then attend 6 weekly visits following the baseline visit to provide fasting blood samples for assessment of serum 25(OH)D concentrations. Analysis of intact-PTH, alkaline-phosphatase, calcium, phosphorus, CRP, TAP and vitamin D metabolite profile and a urine sample will also be obtained for assessment of N-telopeptide and vitamin D metabolite profile will also occur at Baseline and Week 6. Fasting blood samples collected at week 3 will be used for additional assessment of serum alkaline phosphatase, calcium and phosphorus. A 3-day Food Record will be provided at week 3. Vitamin D insufficient participants will be stratified according to their serum 25(OH)D concentrations (≥30 and ≤50, or >50 and ≤75 nmol/L) after screening and prior to the beverage study to ensure that a range of lower and higher serum 25(OH)D concentrations are represented in each beverage group.

Official Title
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A Double-Blind, Randomized, Control Study to Examine the Effects of Vitamin D Fortification on Vitamin D Metabolite Profiles and Status in Vitamin D Insufficient Individuals.

Conditions
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Vitamin D Deficiency

Intervention / Treatment
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* Dietary Supplement: Rooibos Iced-Tea (Control)
* Dietary Supplement: Rooibos Tea - Vitamin D3
* Dietary Supplement: Rooibos Tea- Vitamin D3 & Calcium


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: A. Inclusion Criteria for Objective 1 (Part One): Adult volunteers, male or female, between 19 and 50 years of age; Body mass index (BMI) ≥20 and ≤30 kg/m2 (normal to overweight); Must be on a stable regime for the past three months, if taking vitamin and mineral/dietary/herbal supplements; and Willing to provide informed consent. B. Inclusion Criteria for Objective 2 (Part Two): Adult volunteers, male or female, between 19 and 50 years of age; Body mass index (BMI) ≥20 and ≤30 kg/m2 (normal to overweight); Must be on a stable regime for the past three months, if taking vitamin and mineral/dietary/herbal supplements; Vitamin D insufficient (serum 25(OH)D concentrations ≥30 and ≤75 nmol/L); Willing to comply with protocol requirements; and Willing to provide informed consent. Exclusion Criteria: Take a vitamin D or calcium supplement within the last three months before the start date of the study, or during the study; History of vitamin D deficiency (serum 25(OH)D concentration <30 nmol/L); History of hypocalcaemia; Presence of a clinically diagnosed disease affecting the circulatory, respiratory, immune, skeletal, urinary, muscular, endocrine, digestive, nervous or reproductive system that requires medical treatment; Taking any medication (with the exception of birth control); Daily consumption of more than three servings of dairy products; Undergone significant sun exposure one month before start date of the study; Use or have used a tanning booth one month before start date of the study, or during the study; Plan to travel to a sunny climate during the study; Currently smoking or have smoked within the last six months before start date of the study, or during the study; Have allergies to tea products; Pregnant or lactating; and Consume excessive alcohol (>10 drinks/week for women, >15 drinks/week for men).

Ages Eligible for Study
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Minimum Age: 19 Years
Maximum Age: 50 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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Control<br>Participants will be instructed to consume 240 mL of iced-tea daily for 6 weeks. The iced-tea beverages do not contain added sugar or artificial sweeteners. Beverages will be prepared fresh weekly and picked up by participants during their weekly study visits. | Dietary Supplement: Rooibos Iced-Tea (Control)<br>* Participants will consume 240 mL of Rooibos iced-tea daily for 6 weeks. The iced-tea beverage will not contain any added sugar or artificial sweeteners. Beverages will be prepared fresh weekly and picked up by participants during their weekly study visits.<br>|
| Active Comparator: Rooibos Tea - Vitamin D3<br>Participants will be instructed to consume 240 mL of iced-tea fortified with 1000 IU water-soluable vitamin D3 daily for 6 weeks. The iced-tea beverages do not contain added sugar or artificial sweeteners. Beverages will be prepared fresh weekly and picked up by participants during their weekly study visits. | Dietary Supplement: Rooibos Tea - Vitamin D3<br>* Participants will consume 240 mL of Rooibos iced-tea fortified with 1000 IU of water soluable Vitamin D3 daily for 6 weeks. The iced-tea beverage will not contain any added sugar or artificial sweeteners. Beverages will be prepared fresh weekly and picked up by participants during their weekly study visits.<br>|
| Active Comparator: Rooibos Tea- Vitamin D3 & Calcium<br>Participants will be instructed to consume 240 mL of Rooibos iced-tea fortified with 1000 IU of water-soluable vitamin D3 and 360 mg of calcium daily for 6 weeks. The iced-tea beverages do not contain added sugar or artificial sweeteners. Beverages will be prepared fresh weekly and picked up by participants during their weekly study visits. | Dietary Supplement: Rooibos Tea- Vitamin D3 & Calcium<br>* Participants will consume 240 mL of Rooibos iced-tea fortified with 1000 IU of water soluable Vitamin D3 and 360 mg of Calicum daily for 6 weeks. The iced-tea beverage will not contain any added sugar or artificial sweeteners. Beverages will be prepared fresh weekly and picked up by participants during their weekly study visits.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma/Serum and Urine Vitamin D Metabolite Profiles of Vitamin D Sufficient and Insufficient Individuals | To investigate plasma/serum and urine vitamin D metabolite profiles in vitamin D sufficient and insufficient individuals. | Screening Visit (Day 0) - Phase 1 | 
| The Effects of Vitamin D Fortification on Serum 25(OH)D in Vitamin D Insufficient Individuals. | To determine the effects of 6 weeks of vitamin D3 fortification on serum 25-dihydroxy-vitamin D [25(OH)D] concentrations of vitamin D insufficient individuals. | 6 Weeks (Phase II) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The Effects of Vitamin D3 Fortification on markers of vitamin D of vitamin D insufficient individuals | To determine the effects of 6 weeks of vitamin D3 fortification on markers of vitamin D in plasma/serum and urine of vitamin D insufficient individuals. | 6 Weeks (Phase II) | 
| The Effects of vitamin D3 Fortification on calcium metabolism of Vitamin D Insufficient Individuals. | To determine the effects of 6 weeks of vitamin D3 fortification on calcium metabolism in plasma/serum and urine of vitamin D insufficient individuals. | 6 Weeks (Phase II) | 
| The Effects of Vitamin D3 Fortification on Vitamin D Metabolite Profile of Vitamin D Insufficient Individuals. | Determine the effects of vitamin D3 fortification on the vitamin D metabolite profile in plasma/serum and urine of vitamin D insufficient individuals. | 6 Weeks (Phase II) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Vitamin D insufficient, rooibos tea, calcium