2700 IU of vitamin D needed to get above 20 ng if dark-skinned and high latitude

Created October 2021

Individual participant data (IPD)-level meta-analysis of randomised controlled trials to estimate the vitamin D dietary requirements in dark-skinned individuals resident at high latitude

European Journal of Nutrition (2021) https://doi.org/10.1007/s00394-021-02699-6

Kevin D. Cashman, Mairead E. Kiely, Rikke Andersen, Ida M. Grønborg, Inge Tetens, Laura Tripkovic, Susan A. Lanham-New, Christel Lamberg-Allardt, Folasade A. Adebayo, J. Christopher Gallagher, Lynette M. Smith, Jennifer M. Sacheck, Qiushi Huang, Kimmie Ng, Chen Yuan, Edward L. Giovannucci, Kumaravel Rajakumar, Charity G. Patterson, Inger Öhlund, Torbjörn Lind, Pia Karlsland Åkeson & Christian Ritz

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Context and purpose

There is an urgent need to develop vitamin D dietary recommendations for dark-skinned populations resident at high latitude. Using data from randomised controlled trials (RCTs) with vitamin D3-supplements/fortified foods, we undertook an individual participant data-level meta-regression (IPD) analysis of the response of wintertime serum 25-hydroxyvitamin (25(OH)D) to total vitamin D intake among dark-skinned children and adults residing at  ≥ 40° N and derived dietary requirement values for vitamin D.

Methods

IPD analysis using data from 677 dark-skinned participants (of Black or South Asian descent; ages 5–86 years) in 10 RCTs with vitamin D supplements/fortified foods identified via a systematic review and predefined eligibility criteria. Outcome measures were vitamin D intake estimates across a range of 25(OH)D thresholds.

Results

To maintain serum 25(OH)D concentrations ≥ 25 and 30 nmol/L in 97.5% of individuals, 23.9 and 27.3 µg/day of vitamin D, respectively, were required among South Asian and 24.1 and 33.2 µg/day, respectively, among Black participants. Overall, our age-stratified intake estimates did not exceed age-specific Tolerable Upper Intake Levels for vitamin D.

The vitamin D intake required by dark-skinned individuals to maintain 97.5% of winter 25(OH)D concentrations ≥ 50 nmol/L was 66.8 µg/day . This intake predicted that the upper 2.5% of individuals could potentially achieve serum 25(OH)D concentrations ≥ 158 nmol/L, which has been linked to potential adverse effects in older adults in supplementation studies.

    Note by VitamindDWiki - A dose of Vitamin D is <1/2 as available in seniors, so senior toxicity is not a problem

Conclusions

Our IPD-derived vitamin D intakes required to maintain 97.5% of winter 25(OH)D concentrations ≥ 25, 30 and 50 nmol/L are substantially higher than the equivalent estimates for White individuals. These requirement estimates are also higher than those currently recommended internationally by several agencies, which are based predominantly on data from Whites and derived from standard meta-regression based on aggregate data. Much more work is needed in dark-skinned populations both in the dose–response relationship and risk characterisation for health outcomes.

Trail registration

PROSPERO International Prospective Register of Systematic Reviews (Registration Number: CRD42018097260)

Code availability

The R code for fitting linear and nonlinear models is presented in Cashman KD, Ritz C (2019). Individual participant data (IPD)-level meta-analysis of randomised controlled trials among dark-skinned populations to estimate the dietary requirement for vitamin D. Syst Rev 8:128. https://doi.org/10.1186/s13643-019-1032-6.

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Note: Vitamin D levels need to be >30 ng in those with poor Vitamin D Genes

Genes and Dark Skin- - - - - - -

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Vitamin D Binding Protein and Dark Skin- - - - - - -

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Tags: Darker Skin Predict