Are You Wasting Money on Vitamin D Supplements? New Findings Challenge Widely Held Beliefs on Health Benefits

Many of us hold a vague understanding of the significance of vitamin D, often referred to as the “sunshine vitamin,” in maintaining good health. Despite being the only supplement broadly recommended by the government for all adults, particularly during autumn and winter, its direct benefits remain a topic of heated debate among medical professionals.

While it is commonly associated with promoting healthy teeth and bones, it has recently been linked to a broader range of health benefits.

In a recent study detailed in the journal Nutrients, researchers sought to delve into the potential benefits of vitamin D supplementation on bone and cardiovascular health.

The current investigation was a well-planned, double-blind, placebo-controlled trial of 200 hypertension patients with low blood 25(OH)D levels, namely those less than 75 nmol/L. The study was part of a wider screening effort called the Styrian Hypertension Study, which assessed 518 persons to find potential candidates for the randomized controlled trial (RCT).

The primary goal was to look at the impact of daily vitamin D supplementation at 2,800 international units (IU) over eight weeks on 24-hour systolic ambulatory blood pressure (ABP) and secondary outcomes such as diastolic ABP and other cardiovascular risks.

Ethical permission was received from the Medical University of Graz’s ethics committee, assuring informed consent from all participants. This experiment was extensively recorded in clinical trial registries and adhered to the Consolidated Standards of Reporting Trials (CONSORT) 2010 guidelines.

This research relied on laboratory studies using a validated Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) technique to measure 25(OH)D and 24,25(OH)2D in blood samples maintained at −80°C until October 2023. This approach routinely passed internal and external quality control checks, including Vitamin D External Quality Assessment Scheme (DEQAS) participation. The research examined bone markers such as β-CrossLaps (CTX), osteocalcin, P1NP, and bALP, as well as other laboratory data, using accepted procedures.

This analysis re-analyzed the main and secondary outcomes from the previous RCT, taking into account additional factors linked to bone and mineral metabolism.

The statistical analysis was rigorous, using analysis of covariance (ANCOVA) for group comparisons, with a special emphasis on those with functional vitamin D deficiency.

The research gathered exact VMR data for 505 of the original 518 participants. Among them, 192 had vitamin D deficiency, as shown by 25(OH)D levels below 50 nmol/L. This difference paved the way for an in-depth investigation of vitamin D metabolites and their health consequences, with the participants’ baseline characteristics meticulously catalogued and stratified depending on their 25(OH)D concentration. The classification of blood levels below and over 50 nmol/L offered a clear comparison framework for measuring vitamin D status across the cohort.

Further data separation was done by comparing patients with 25(OH)D levels of less than 50 nmol/L and classifying them based on the presence or absence of functional vitamin D deficiency. The data ranged from baseline measures to follow-up assessments, documenting changes in mineral metabolism and cardiovascular health indicators. This longitudinal view was critical for understanding the dynamic nature of vitamin D’s influence on health outcomes throughout supplementation.

The investigation of cardiovascular risk variables was especially informative, providing insights into how vitamin D supplementation may affect heart health and associated risk profiles in people with low blood 25(OH)D levels and functional vitamin D deficiency.

Furthermore, when the data was evaluated via a gender-specific lens, the findings were consistent, demonstrating that the observed benefits of vitamin D supplementation and the consequences of functional vitamin D insufficiency were the same for male and female individuals.

To summarize, the study discovered that hypertensive patients with vitamin D deficiency, particularly those with functional vitamin D deficiency, did not benefit significantly from vitamin D supplementation, with the exception of a decrease in parathyroid hormone (PTH) levels.

One significant discovery emerged from the study: individuals with functional vitamin D deficiency exhibited a heightened prevalence of diabetes and glucose metabolism disorders. Despite employing sophisticated LC-MS/MS methods to accurately measure vitamin D metabolites, substantial health improvements remained elusive.

This underscores the intricate regulation of vitamin D metabolism and emphasizes the necessity for additional research to investigate the effects of vitamin D supplementation on individuals grappling with functional vitamin D deficiency.

Image Credit: Getty