The Effect of Vitamin D Supplementation on its Metabolism and the Vitamin D Metabolite Ratio

Abstract

25-hydroxyvitamin D (25(OH)D) is commonly measured to assess vitamin D status. Other vitamin D metabolites such as 24,25-dihydroxyvitamin D (24,25(OH)2D) provide additional insights into vitamin D status or metabolism. Earlier studies suggested that the vitamin D metabolite ratio (VMR), calculated as 24,25(OH)2D/25(OH)D, could predict the 25(OH)D increase after vitamin D supplementation. However, the evidence for this additional value is inconclusive. Therefore, our aim was to assess whether the increase in 25(OH)D after supplementation was predicted by the VMR better than baseline 25(OH)D. Plasma samples of 106 individuals (25(OH)D < 75 nmol/L) with hypertension who completed the Styrian Vitamin D Hypertension Trial (NC.T.02136771) were analyzed. Participants received vitamin D (2800 IU daily) or placebo for 8 weeks. The treatment effect (ANCOVA) for 25(OH)D3, 24,25(OH)2D3 and the VMR was 32 nmol/L, 3.3 nmol/L and 0.015 (all p < 0.001), respectively. Baseline 25(OH)D3 and 24,25(OH)2D3 predicted the change in 25(OH)D3 with comparable strength and magnitude. Correlation and regression analysis showed that the VMR did not predict the change in 25(OH)D3. Therefore, our data do not support routine measurement of 24,25(OH)2D3 in order to individually optimize the dosage of vitamin D supplementation. Our data also suggest that activity of 24-hydroxylase increases after vitamin D supplementation.

Effects of Vitamin D3 Supplementation and Resistance Training on 25-Hydroxyvitamin D Status and Functional Performance of Older Adults: A Randomized Placebo-Controlled Trial

“…In contrast, the VDM group received 200,000 IU vitamin D3 supplemented as 50,000 IU per month, which would correspond to an amount of 1785 IU/d. A slightly higher improvement of 61% has been shown previously with a smaller total amount but a higher daily dose of 2800 IU/d vitamin D3 for eight weeks in a comparable population [ 37 ]. Similar data are provided in a dose–response study where 25(OH)D concentrations increased with dose and were highest at 50,000 IU/week, followed by 4000 IU/d, 2000 IU/d and 800 IU/day with no differences between the latter two [ 38 ].…”

Efficacy of Vitamin D3 Buccal Spray Supplementation Compared to Other Delivery Methods: A Systematic Review of Superiority Randomized Controlled Trials

“…Inclusion criteria were RCTs on (1) any population, including healthy participants or patients, (2) populations with low serum 25(OH)D concentrations, (3) of any age group, (4) living in any country, (5) comparing vitamin D 3 buccal spray against other routes of vitamin D 3 delivery (i.e., oral drops, capsules), (6) performed on humans, (7) using any RCT design, (8) published in any language.…”

“…independently extracted characteristics of the retrieved RCTs and outcomes of interest from full-text articles. Extracted data involved (1) the number of participants at each stage, (2) participant characteristics, (3) study characteristics (registry, design, ethical approval, country, funding), (4) administered dose of vitamin D3 and methods of delivery, (5) intervention duration, (6) washout period (whenever applicable), (7) participant recruitment sites, (8) assays and kits for determining 25(OH)D levels, (9) baseline and post-intervention results (including 25(OH)D, Ca, and parathyroid hormone (PTH) concentrations), (10) recorded adverse events, (11) drop-outs, and (12) analysis performed (intention-to-treat or per protocol).…”

“…Vitamin D 3 is an essential fat-soluble nutrient involved in a plethora of metabolic pathways [1][2][3][4][5]. When consumed within the dietary reference level limits, vitamin D exerts multiple health…”

Calcium, Vitamin D, and Health

“…This study strengthens the idea that a single measurement of total 25(OH)D may not be enough to fully reflect all changes in vitamin D metabolism in MS patients. In a randomized clinical trial conducted in hypertensive adults, Francic et al [9] did not support the routine measurement of 24,25 dihydroxycholecalciferol (24,25(OH)2D3) in order to individually optimize the dosage of vitamin D supplementation. Interestingly, the activity of 24-hydroxylase increased after vitamin D supplementation.…”