The Genetic Effects on Vitamin D Supplementation

Effects of VDR rs7311856, GC rs2282679 and CYP2R1 rs2060793 Variants on Vitamin D Status: A Randomised Control Trial

Vitamin D is essential for skeletal growth and bone health, deficiency causes rickets and osteomalacia. In the UK 29% of adults have vitamin D deficiency. It is recommended all adults take 10µg vitamin D supplement daily. Genetic variations could alter vitamin D status by affecting vitamin D metabolism. Systematic reviews found variations in VDR, GC and CYP2R1 genes are associated with vitamin D deficiency. This study aims to assess the effects between vitamin D supplementation and variations in VDR, GC and CYP2R1 genes on vitamin D status.

The study design is a quantitative, randomised control trial measuring vitamin D concentrations in blood serum. All participants will be given the recommended 10µg daily dose of vitamin D supplementation. Participants will be grouped based on their genotype for each gene, as either low, medium or high-risk genotypes. The low-risk group will act as a control and the medium and high-risk groups will act as the intervention groups. Participants will attend St Mary's University's applied science laboratory twice. During their first visit participants will provide a 2ml capillary blood sample. Blood samples are collected using lancets to prick participants' ear lobes. The serum is extracted from the blood samples, serum is stored at -80c until analysis. Participants will be given 90 10µg vitamin D supplements and instructed to take one per day for 90 days. Participants will also be instructed to not make any major changes to their habitual diet. During the second visit participants will provide 1 ml of saliva sample into the Collection Pot and a second 2ml sample of blood. Serum samples will be analysed for vitamin D concentrations using 25(OH) Vitamin D ELISA kit. DNA will be extracted from the saliva samples using PSP SalivaGene DNA Kit following the manufacturer's protocol. DNA will be genotyped for variations in the VDR, GC and CYP2R1 genes. Data will be assessed to determine if variations in these genes influenced the effectiveness of vitamin D supplementation.

Participants are grouped based on their genetic risk of vitamin D deficiency, all participants are given 10µg vitamin D supplements for 90 days

Participants with no genetic variation in their VDR, GC and CYP2R1 genes that would increase their risk of vitamin D deficiency. Participants will be given 10µg vitamin D supplements for 90 days. This group is a control against the medium and high-risk intervention groups.

Participants with genetic variation in their VDR, GC and CYP2R1 genes that moderately increase their risk of vitamin D deficiency. Participants will be given 10µg vitamin D supplements for 90 days. This group will be compared against the low-risk control group to determine the effect of genetic variations on vitamin D status.

Participants with genetic variation in their VDR, GC and CYP2R1 genes that increase their risk of vitamin D deficiency. Participants will be given 10µg vitamin D supplements for 90 days. This group will be compared against the low-risk control group to determine the effect of genetic variations on vitamin D status.

Inclusion Criteria: Healthy adults female and male 18-65 years completion of physical activity readiness questionnaire (PAR-Q). Exclusion Criteria: Below 18 years above 65 years individuals taking medications that could interact with vitamin D status Individuals regularly taking daily Vitamin D supplementation during the 3 months before the intervention start date major dietary changes in vitamin D intake during the intervention period

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National Health Service (NHS) (2020) Vitamin D. Available at: https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/

National Institute for Health and Care Excellence (NICE) (2017) Vitamin D: supplement use in specific population groups. Available at: https://www.nice.org.uk/guidance/ph56/

Public Health England (PHE) (2019) National Diet and Nutrition Survey: Years 1 to 9 of the Rolling Programme (2008/2009 - 2016/2017): Time trend and income analyses. Available at: https://assets.publishing.service.gov.uk/

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