Effects of Vitamin D Fortification on Vitamin D Metabolite Profiles and Status in Vitamin D Insufficient Individuals
Effects of Vitamin D Fortification on Vitamin D Metabolite Profiles and Status in Vitamin D Insufficient Individuals
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.
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.
Inclusion Criteria:

 A. Inclusion Criteria for Objective 1 (Part One):

 1. Adult volunteers, male or female, between 19 and 50 years of age;

 2. Body mass index (BMI) ≥20 and ≤30 kg/m2 (normal to overweight);

 3. Must be on a stable regime for the past three months, if taking vitamin and
 mineral/dietary/herbal supplements; and

 4. Willing to provide informed consent.

 B. Inclusion Criteria for Objective 2 (Part Two):

 1. Adult volunteers, male or female, between 19 and 50 years of age;

 2. Body mass index (BMI) ≥20 and ≤30 kg/m2 (normal to overweight);

 3. Must be on a stable regime for the past three months, if taking vitamin and
 mineral/dietary/herbal supplements;

 4. Vitamin D insufficient (serum 25(OH)D concentrations ≥30 and ≤75 nmol/L);

 5. Willing to comply with protocol requirements; and

 6. Willing to provide informed consent.

 Exclusion Criteria:

 1. Take a vitamin D or calcium supplement within the last three months before the start
 date of the study, or during the study;

 2. History of vitamin D deficiency (serum 25(OH)D concentration <30 nmol/L);

 3. History of hypocalcaemia;

 4. Presence of a clinically diagnosed disease affecting the circulatory, respiratory,
 immune, skeletal, urinary, muscular, endocrine, digestive, nervous or reproductive
 system that requires medical treatment;

 5. Taking any medication (with the exception of birth control);

 6. Daily consumption of more than three servings of dairy products;

 7. Undergone significant sun exposure one month before start date of the study;

 8. Use or have used a tanning booth one month before start date of the study, or during
 the study;

 9. Plan to travel to a sunny climate during the study;

 10. Currently smoking or have smoked within the last six months before start date of the
 study, or during the study;

 11. Have allergies to tea products;

 12. Pregnant or lactating; and

 13. Consume excessive alcohol (>10 drinks/week for women, >15 drinks/week for men).