Clinical trial NCT06067477: Estimation of the Dietary Requirement for Vitamin D in Ethnic Groups
Official title: Estimation of the Dietary Requirement for Vitamin D in Ethnic Groups: a Double-blind, Randomised, Dose-response Trial
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Vitamin D Deficiency
Immune Health
Muscle Function
Lead sponsor: University of Surrey
Sponsor class: OTHER
Collaborators: name: University of Reading
First posted: 2023-10-05
Enrollment: 114
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention model description: Recruited participants will be randomised to take 400,1000, or 2000 IU for 12 weeks.
Primary purpose: PREVENTION

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.

Eligibility criteria: 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

Primary outcomes:
measure: Concentration of serum 25(OH)D (nmol/L)
timeFrame: Baseline and 12 weeks
Secondary outcomes:
measure: Anthropometric measurements - weight (kg)
timeFrame: Baseline and 12 weeks
measure: Anthropometric measurements - height (m)
timeFrame: Baseline and 12 weeks
measure: Anthropometric measurements - height (cm)
timeFrame: Baseline and 12 weeks
measure: Anthropometric measurements - waist circumference (cm)
timeFrame: Baseline and 12 weeks
measure: Anthropometric measurements - hip circumference (cm)
timeFrame: Baseline and 12 weeks
measure: Concentration of serum calcium (nmol/L)
timeFrame: Baseline and 12 weeks
measure: Concentration of plasma parathyroid hormone (PTH) (pg/mL)
timeFrame: Baseline and 12 weeks
measure: Concentration of serum albumin (g/L)
timeFrame: Baseline and 12 weeks
measure: Concentration of C-Reactive Protein (CRP) (mg/L)
timeFrame: Baseline and 12 weeks
measure: Complete blood count
timeFrame: Baseline and 12 weeks
measure: Change in immune parameters
timeFrame: Baseline and 12 weeks
measure: Number of participants with Acute Respiratory Tract Infections (ARTIs)
timeFrame: 12 weeks
measure: Muscular strength using a handgrip strength test (kg)
timeFrame: Baseline and 12 weeks
measure: Muscular strength and endurance using a sit-to-stand test
timeFrame: Baseline and 12 weeks
measure: Blood analytes - micronutrient status
timeFrame: Baseline and 12 weeks
measure: Blood analytes - lipid profile (mg/dL)
timeFrame: Baseline and 12 weeks
measure: Vitamin D consumption from diet
timeFrame: Baseline and 12 weeks
measure: Physical activity questionnaire
timeFrame: Baseline
measure: Sun exposure behaviour questionnaire
timeFrame: Baseline
measure: Ultraviolet B radiation (UVB) sun exposure
timeFrame: Baseline and 12 weeks
measure: Lifestyle questionnaire
timeFrame: Baseline
Other outcomes:
Locations:
city: Guildford
country: United Kingdom
facility: Faculty of Health and Medical Sciences
Study officials:
affiliation: University of Surrey
name: Abigail Bournot
role: PRINCIPAL_INVESTIGATOR
References: