Vitamin D in human serum and adipose tissue after supplementation

Cora M Best; Devon V Riley; Thomas J Laha; Hannah Pflaum; Leila R Zelnick; Simon Hsu; Kenneth E Thummel; Karen E Foster-Schubert; Jessica N Kuzma; Gail Cromer; Ilona Larson; Derek K Hagman; Kelly Heshelman; Mario Kratz; Ian H de Boer; Andrew N Hoofnagle

doi:10.1093/ajcn/nqaa295

Vitamin D in human serum and adipose tissue after supplementation

Am J Clin Nutr. 2021 Jan 4;113(1):83-91. doi: 10.1093/ajcn/nqaa295.

Authors

Cora M Best^{1

2}, Devon V Riley¹, Thomas J Laha¹, Hannah Pflaum¹, Leila R Zelnick^{2

3}, Simon Hsu^{2

3}, Kenneth E Thummel⁴, Karen E Foster-Schubert^{3

5}, Jessica N Kuzma⁶, Gail Cromer⁶, Ilona Larson⁶, Derek K Hagman⁶, Kelly Heshelman⁶, Mario Kratz^{3

6

7}, Ian H de Boer^{2

3

7}, Andrew N Hoofnagle^{1

2

3}

Affiliations

¹ Department of Laboratory Medicine, University of Washington, Seattle, WA, USA.
² Kidney Research Institute, University of Washington, Seattle, WA, USA.
³ Department of Medicine, University of Washington, Seattle, WA, USA.
⁴ Department of Pharmaceutics, University of Washington, Seattle, WA, USA.
⁵ VA Puget Sound Healthcare System, Seattle, WA, USA.
⁶ Cancer Prevention Program, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
⁷ Department of Epidemiology, University of Washington, Seattle, WA, USA.

Abstract

Background: Serum 25-hydroxyvitamin D [25(OH)D] concentration is an indicator of vitamin D exposure, but it is also influenced by clinical characteristics that affect 25(OH)D production and clearance. Vitamin D is the precursor to 25(OH)D but is analytically challenging to measure in biological specimens.

Objectives: We aimed to develop and validate a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantification of vitamins D3 and D2 in serum and to explore the potential of circulating vitamin D as a biomarker of exposure in supplementation trials.

Methods: The method was validated using guideline C62-A from the Clinical and Laboratory Standards Institute and was applied in 2 pilot clinical trials of oral vitamin D3 supplementation. Pilot study 1 included 22 adults randomly assigned to placebo or 2000 IU/d. Blood was collected at baseline, 1, 3, 6, and 12 mo. Pilot study 2 included 15 adults randomly assigned to 2000 or 4000 IU/d. Blood and subcutaneous (SUBQ) adipose tissue were collected at baseline and 3 mo.

Results: In study 1, mean change (baseline to 3 mo) in serum vitamin D3 was -0.1 ng/mL in the placebo group and 6.8 ng/mL in the 2000 IU/d group (absolute difference: 6.9; 95% CI: 4.5, 9.3 ng/mL). In study 2, mean change (baseline to 3 mo) in serum vitamin D3 was 10.4 ng/mL in the 2000 IU/d group and 22.2 ng/mL in the 4000 IU/d group (fold difference: 2.15; 95% CI: 1.40, 3.37). Serum and adipose tissue vitamin D3 concentrations were correlated, and the dose-response of vitamin D3 in adipose mirrored that in serum.

Conclusions: We validated a sensitive, robust, and high-throughput LC-MS/MS method to quantify vitamins D3 and D2 in serum. Serum and SUBQ adipose tissue vitamin D3 concentrations increased proportionally to dose with 3 mo of daily supplementation.These trials were registered at clinicaltrials.gov as NCT00552409 (pilot study 1) and NCT01477034 (pilot study 2).

Keywords: Clinical and Laboratory Standards Institute; cholecalciferol; ergocalciferol; liquid chromatography–tandem mass spectrometry; liquid-liquid extraction; validation; vitamin D.

Associated data

ClinicalTrials.gov/NCT00552409
ClinicalTrials.gov/NCT01477034

Abstract

Associated data

Grants and funding