Vitamin D Deficiency, Immune Health, Muscle Function
Conditions
Brief summary
The aim of this study is to perform a double-blind, randomised, dose-response trial of vitamin D3 supplementation in United Kingdom (UK)-dwelling adults of white European, South Asian, and black African/Caribbean ethnicity to investigate the distribution of dietary intakes needed to maintain adequate vitamin D status in winter, as indicated by serum 25(OH)D concentrations at ranges of \>25 to 50 nmol/L. In addition, this study will investigate the effect of vitamin D3 supplementation on immune health, muscular strength, and overall health.
Detailed description
The aim of this study is to perform a double-blind, randomised, dose-response trial of vitamin D3 supplementation in United Kingdom (UK)-dwelling adults of white European, South Asian, and black African/Caribbean ethnicity to investigate the distribution of dietary intakes needed to maintain adequate vitamin D status in winter, as indicated by serum 25(OH)D concentrations at ranges of \>25 to 50 nmol/L. In addition, this study will investigate the effect of vitamin D3 supplementation on immune health, muscular strength, and overall health. Recruited participants will be randomised to take 400, 1000, or 2000 IU for 12 weeks. Fasting blood samples collected at baseline and 12 weeks will measure biochemical markers of vitamin D status (serum 25(OH)D, calcium, parathyroid hormone, albumin), lipid profile, ferritin, micronutrient status, and immune and inflammatory biomarkers. Muscular strength will be measured using sit-to-stand and grip strength tests. Questionnaires, food diaries, and dosimeters will be used to gather data on lifestyle, physical activity, dietary intake, and sun exposure.
Interventions
DIETARY_SUPPLEMENTVitamin D Supplement
Vitamin D Supplement
Sponsors
University of Reading
University of Surrey
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
DOUBLE (Subject, Investigator)
Intervention model description
Recruited participants will be randomised to take 400,1000, or 2000 IU for 12 weeks.
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* British white European, black African/Caribbean, or South Asian (self-reported) * Living in England for \>2 months * Aged \>18 years * No significant health issues * English or Urdu speaker
Exclusion criteria
* Medical condition or history which might impact study measurements (e.g., ischaemic heart disease, type 1 and type 2 diabetes, thyroid disease, osteoporosis, haematological disease, malignancy) * Medications known to affect vitamin D metabolism (i.e., hormone replacement therapy, anti-oestrogens treatment, antiepileptic drugs, and breast cancer treatment) * Pregnant or planning pregnancy during the study period * Regular use of sun beds * Having a sun holiday one month prior to commencing study or plans for a sun holiday within the study period. A sun holiday is generally defined as a holiday in a sunny resort outside of the UK. The researchers will assess this on a case-by-case basis depending on the time of year and expected weather conditions * Reported participation in another clinical trial occurring simultaneously * Previous intolerance or allergic reaction to vitamin D
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Concentration of serum 25(OH)D (nmol/L) | Baseline and 12 weeks | A blood sample will be analysed using liquid chromatography tandem mass spectroscopy (LC-MS). Dose-response change in serum 25(OH)D will be measured in nmol/L. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Anthropometric measurements - height (m) | Baseline and 12 weeks | Height (m) |
| Anthropometric measurements - height (cm) | Baseline and 12 weeks | Height (cm) |
| Anthropometric measurements - waist circumference (cm) | Baseline and 12 weeks | Waist circumference measurement (cm) |
| Anthropometric measurements - hip circumference (cm) | Baseline and 12 weeks | Hip circumference measurement (cm) |
| Concentration of serum calcium (nmol/L) | Baseline and 12 weeks | Measure dose-response change in serum calcium measured in nmol/L |
| Concentration of plasma parathyroid hormone (PTH) (pg/mL) | Baseline and 12 weeks | Measure dose-response change in plasma parathyroid hormone (PTH) measured in pg/mL |
| Concentration of serum albumin (g/L) | Baseline and 12 weeks | Measure dose-response change in serum albumin measured in g/L |
| Concentration of C-Reactive Protein (CRP) (mg/L) | Baseline and 12 weeks | Measure dose-response change in CRP measured in mg/L |
| Complete blood count | Baseline and 12 weeks | Measure change in complete blood count |
| Change in immune parameters | Baseline and 12 weeks | Measure change in gene expression in white blood cells |
| Anthropometric measurements - weight (kg) | Baseline and 12 weeks | Weight (kg) |
| Muscular strength using a handgrip strength test (kg) | Baseline and 12 weeks | Muscular strength measured using a dynamometer (measured to the nearest 0.1kg). The participant will squeeze the dynamometer with maximum effort for 5 seconds. |
| Muscular strength and endurance using a sit-to-stand test | Baseline and 12 weeks | Number of sit to stands in 30 seconds |
| Blood analytes - micronutrient status | Baseline and 12 weeks | Measure dose-response change in micronutrient status from blood samples |
| Blood analytes - lipid profile (mg/dL) | Baseline and 12 weeks | Measure change in lipid profile from blood samples measured in mg/dL |
| Vitamin D consumption from diet | Baseline and 12 weeks | Vitamin D intake will be measured through a 4-day food diary which participants will fill out for 4 day at home before and after the study. |
| Physical activity questionnaire | Baseline | Assess level of physical activity using an International Physical Activity Questionnaire (short form) |
| Sun exposure behaviour questionnaire | Baseline | Measures amount of time spent in the sun (often, occasionally, never) and what parts of the body are exposed (head, hands, arms, legs, torso) over summer, spring, autumn and winter. Also questions any summer holidays abroad, in what month, what country was visited, number of hours of sun per day and what body parts were exposed (head, hands, arms, legs, torso) |
| Ultraviolet B radiation (UVB) sun exposure | Baseline and 12 weeks | Sun exposure will be measured by a dosimeter, which measures UVB exposure. Participants wear this like a badge for 4 days before and after the study. |
| Lifestyle questionnaire | Baseline | Measures: \- Skin type (Fitzpatrick scale) Questions: Questions what ethnicity they identify with, Holidays abroad, Education, Origin, Health, Pregnancy, Sun behaviours (what body parts are usually exposed to the sun, clothing, sun bathing, sunscreen use, sun bed use), Smoking, Drinking, Recreational drug use, Knowledge around vitamin D, supplement use, Milk, egg, oily fish and liver consumption |
| Number of participants with Acute Respiratory Tract Infections (ARTIs) | 12 weeks | Measure the frequency of ARTIs using a validated questionnaire |
Countries
United Kingdom
Contacts
Primary ContactAbigail Bournot, PhD
Backup ContactSusan Lanham-New
Outcome results
None listed