Epigenetics Predicts Serum 25-Hydroxyvitamin D Response to Vitamin D3 Supplementation in African Americans

Effect of epigenetics on vitamin D levels: a systematic review until December 2020

BACKGROUND

The association between epigenetic modification of the genes involved in the vitamin D metabolic pathway and vitamin D metabolites' status has been elucidated incompletely. This study aims to review the studies on the mentioned association and create a brighter view of this topic.

METHODS

A systematic literature search was conducted in Medline database (PubMed), Scopus, and Web of Science up to the end of November 2020. Original articles which reported the effect of epigenetic alteration-methylation level or its changes-of genes involved in vitamin D regulation on the vitamin D metabolites serum level or its changes were included. The National Institutes of Health (NIH) checklist was used to assess the quality of included articles.

RESULTS

Among 2566 records, nine reports were included in the systematic review according to the inclusion and exclusion criteria. Studies discussed the contribution of methylation status of members of the cytochrome P450 family (CYP2R1, CYP27B1, CYP24A1), and Vitamin D Receptor (VDR) genes to vitamin D level variance. CYP2R1 methylation status could regulate the contributing factors affecting the vitamin D serum level and predict response to vitamin D supplementation. Studies revealed that impaired methylation of CYP24A1 occurs in response to an increase in serum level of 25-hydroxyvitamin D (25(OH)D). It is reported that the association between methylation levels of CYP2R1, CYP24A1, and VDR genes and 25(OH)D level is not affected by the methyl-donors bioavailability.

CONCLUSIONS

The epigenetic modification of the vitamin D-related genes could explain the vitamin D levels variation among populations. Large-scale clinical trials in various ethnicities are suggested to find the effect of epigenetics on vitamin D response variation.

REGISTRATION

The systematic review protocol was registered on PROSPERO (registration number: CRD42022306327).

Epigenetic regulation of vitamin D deficiency

Tweetable abstract Epigenetic insights into vitamin D deficiency, a global health concern, are described here. This editorial illuminates the role of epigenetic mechanisms in understanding the molecular basis of vitamin D deficiency, shedding light on precision medicine.

Changes in 25-hydroxyvitamin D levels post-vitamin D supplementation in people of Black and Asian ethnicities and its implications during COVID-19 pandemic: A systematic review

BACKGROUND

People of Black and Asian ethnicities have a higher infection rate and mortality as a result of COVID-19. It has also been reported that vitamin D deficiency may play a role in this, possibly because of the multi-gene regulatory function of the vitamin D receptor. As a result, increased dietary intake and/or supplementation to attain adequate 25-hydroxyvitamin D (25(OH)D) levels could benefit people in these ethnicities. The present study aimed to review the literature examining the changes in 25(OH)D in different types of vitamin D supplementation from randomised controlled trials in this population.

METHODS

This systematic review was conducted using the PRISMA guidelines. Electronic databases were systematically searched using keywords related to vitamin D supplementation in Black and Asian ethnicities.

RESULTS

Eight studies were included in the review. All the included studies found that supplementation of vitamin D (D₂ and D₃ ), regardless of dosage, increased 25(OH)D levels compared to a placebo. All trials in which participants were vitamin D deficient at baseline showed increased 25(OH)D levels to a level considered adequate. Two studies that used food fortification yielded smaller 25(OH)D increases compared to similar studies that used oral supplementation (10.2 vs. 25.5 nmol L^-1 , respectively). Furthermore, vitamin D₂ supplementation yielded significantly lower 25(OH)D increases than vitamin D₃ supplementation.

CONCLUSIONS

Oral vitamin D supplementation may be more efficacious in increasing 25(OH)D levels than food fortification of Black and Asian ethnicities, with vitamin D₃ supplementation possibly being more efficacious than vitamin D₂ . It is recommended that people with darker skin supplement their diet with vitamin D₃ through oral tablet modes where possible, with recent literature suggesting a daily intake of 7000-10,000 IU to be potentially protective from unfavourable COVID-19 outcomes. As a result of the paucity of studies, these findings should be treated as exploratory.