Estimation of the Dietary Requirement for Vitamin D in Ethnic Groups

Vitamin D Deficiency Clinical Trial

Official title:

Estimation of the Dietary Requirement for Vitamin D in Ethnic Groups: a Double-blind, Randomised, Dose-response Trial

Clinical Trial Details — Status: Recruiting

Administrative data

• NCT number: NCT06067477
• Other study ID #: FHMS 22-23 194 EGA
• Status: Recruiting
• Phase: N/A
• Start date: November 1, 2023
• Est. completion date: September 2025

Study information

• Verified date: May 2024
• Source: University of Surrey
• Contact: Abigail Bournot, PhD
• Phone: 01483689222
• Email: a.bournot[@]surrey.ac.uk
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial 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.

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.

Recruitment information / eligibility

• Status: Recruiting
• Enrollment: 114
• Est. completion date: September 2025
• Est. primary completion date: September 2025
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years and older

Eligibility

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

Related Conditions & MeSH terms

• Immune Health
• Muscle Function
• Vitamin D Deficiency

Intervention

Dietary Supplement:
• Vitamin D Supplement
Vitamin D Supplement

Locations

Country	Name	City	State
United Kingdom	Faculty of Health and Medical Sciences	Guildford

Sponsors (2)

Lead Sponsor	Collaborator
University of Surrey	University of Reading

Country where clinical trial is conducted

United Kingdom, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Concentration of serum 25(OH)D (nmol/L)	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.	Baseline and 12 weeks
Secondary	Anthropometric measurements - weight (kg)	Weight (kg)	Baseline and 12 weeks
Secondary	Anthropometric measurements - height (m)	Height (m)	Baseline and 12 weeks
Secondary	Anthropometric measurements - height (cm)	Height (cm)	Baseline and 12 weeks
Secondary	Anthropometric measurements - waist circumference (cm)	Waist circumference measurement (cm)	Baseline and 12 weeks
Secondary	Anthropometric measurements - hip circumference (cm)	Hip circumference measurement (cm)	Baseline and 12 weeks
Secondary	Concentration of serum calcium (nmol/L)	Measure dose-response change in serum calcium measured in nmol/L	Baseline and 12 weeks
Secondary	Concentration of plasma parathyroid hormone (PTH) (pg/mL)	Measure dose-response change in plasma parathyroid hormone (PTH) measured in pg/mL	Baseline and 12 weeks
Secondary	Concentration of serum albumin (g/L)	Measure dose-response change in serum albumin measured in g/L	Baseline and 12 weeks
Secondary	Concentration of C-Reactive Protein (CRP) (mg/L)	Measure dose-response change in CRP measured in mg/L	Baseline and 12 weeks
Secondary	Complete blood count	Measure change in complete blood count	Baseline and 12 weeks
Secondary	Change in immune parameters	Measure change in gene expression in white blood cells	Baseline and 12 weeks
Secondary	Number of participants with Acute Respiratory Tract Infections (ARTIs)	Measure the frequency of ARTIs using a validated questionnaire	12 weeks
Secondary	Muscular strength using a handgrip strength test (kg)	Muscular strength measured using a dynamometer (measured to the nearest 0.1kg). The participant will squeeze the dynamometer with maximum effort for 5 seconds.	Baseline and 12 weeks
Secondary	Muscular strength and endurance using a sit-to-stand test	Number of sit to stands in 30 seconds	Baseline and 12 weeks
Secondary	Blood analytes - micronutrient status	Measure dose-response change in micronutrient status from blood samples	Baseline and 12 weeks
Secondary	Blood analytes - lipid profile (mg/dL)	Measure change in lipid profile from blood samples measured in mg/dL	Baseline and 12 weeks
Secondary	Vitamin D consumption from diet	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.	Baseline and 12 weeks
Secondary	Physical activity questionnaire	Assess level of physical activity using an International Physical Activity Questionnaire (short form)	Baseline
Secondary	Sun exposure behaviour questionnaire	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)	Baseline
Secondary	Ultraviolet B radiation (UVB) sun exposure	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.	Baseline and 12 weeks
Secondary	Lifestyle questionnaire	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	Baseline