In a recent study published in the journal Nutrients, the researchers revealed that hypertensive patients with vitamin D deficiency did not experience significant improvements in bone health or cardiovascular risk factors from vitamin D supplementation, except for a reduction in parathyroid hormone (PTH) levels.
The study involved a meticulously planned double-blind, placebo-controlled trial, which focused on 200 hypertensive patients with low serum 25(OH)D levels, specifically below 75 nmol/L. This trial was part of a broader screening effort known as the Styrian Hypertension Study, which initially assessed 518 participants to identify suitable candidates for the randomized controlled trial (RCT). The study used a validated Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) method to measure both 25(OH)D and 24,25-dihydroxyvitamin D (24,25(OH)2D) levels in serum samples stored at −80°C until October 2023. The study also encompassed various bone markers and laboratory parameters related to bone and mineral metabolism.
The analysis of the data included a focus on the vitamin D metabolite ratio (VMR), which was meticulously collected for 505 out of the initial 518 participants. Among these, 192 were identified as having vitamin D deficiency, defined by 25(OH)D levels <50 nmol/L. This categorization facilitated a comprehensive exploration of vitamin D metabolites and their health implications, with participants’ baseline characteristics thoroughly cataloged and stratified based on their 25(OH)D concentrations.
Further differentiation within the data was achieved by comparing participants with 25(OH)D levels under 50 nmol/L based on the presence or absence of functional vitamin D deficiency. This longitudinal analysis captured changes in mineral metabolism and cardiovascular health parameters from baseline to follow-up, providing valuable insights into the dynamic nature of vitamin D’s impact on health outcomes during supplementation. The study revealed that hypertensive patients with vitamin D deficiency, particularly those with functional vitamin D deficiency, did not experience significant improvements in bone health or cardiovascular risk factors from vitamin D supplementation, except for a reduction in parathyroid hormone (PTH) levels. Individuals with functional deficiency exhibited a higher prevalence of diabetes and glucose metabolism disorders.
Even with advanced LC-MS/MS methods for precise vitamin D metabolite measurement, significant health benefits from supplementation remained elusive, underscoring the complexity of vitamin D metabolism regulation. This research highlights the necessity for further studies to explore the impact of vitamin D supplementation on individuals with functional vitamin D deficiency and underscores the importance of refining the assessment of vitamin D status beyond serum 25(OH)D levels alone.
Reference
Zelzer S, Meinitzer A, Enko D, Keppel MH, Herrmann M, Theiler-Schwetz V, et al. Classification of Vitamin D Status Based on Vitamin D Metabolism: A Randomized Controlled Trial in Hypertensive Patients. Nutrients. 2024 Jan;16(6):839.