Magnesium status and supplementation influence vitamin D status and metabolism: results from a randomized trial.
Level 2 - randomized trial
Individual double-blind randomized controlled trial.
PubMed 30541089 · doi:10.1093/ajcn/nqy274
What was done
Double-blind randomized controlled trial nested within the Personalized Prevention of Colorectal Cancer Trial (PPCCT) involving 180 participants aged 40–85 years. Doses of magnesium or placebo were customized based on baseline dietary intakes, and participants were assigned via permuted-block randomization. Changes in plasma concentrations of 25-hydroxyvitamin D3 [25(OH)D3], 25(OH)D2, 1,25-dihydroxyvitamin D3, 1,25-dihydroxyvitamin D2, and 24,25-dihydroxyvitamin D3 [24,25(OH)2D3] were measured using liquid chromatography-mass spectrometry.
What was found
The effect of magnesium supplementation on plasma vitamin D metabolites depended significantly on baseline 25(OH)D concentrations (interactions remained significant after Bonferroni correction). Magnesium increased 25(OH)D3 when baseline 25(OH)D was close to 30 ng/mL, but decreased 25(OH)D3 when baseline 25(OH)D was higher (~30 to 50 ng/mL). Magnesium significantly altered 24,25(OH)2D3 at baseline 25(OH)D levels of 50 ng/mL but not at 30 ng/mL. In addition, magnesium increased 25(OH)D2 as baseline 25(OH)D increased. Absolute effect estimates and confidence intervals were not reported in the abstract.
Why it matters
This trial provides experimental human evidence that magnesium status regulates vitamin D metabolism bi-directionally, suggesting that magnesium adequacy is required to optimize circulating 25(OH)D levels rather than simply driving higher concentrations.
Limits
The study is an ancillary analysis of 180 participants aged 40–85 years from a single medical center trial. Exact numerical changes, intervention duration, adverse events, and clinical health outcomes were not reported in the abstract.
Cited by
- supports A randomized controlled trial demonstrated that magnesium supplementation increased circulating 25-hydroxyvitamin D levels in individuals with low baseline vitamin D status.
- supports Magnesium is required to convert vitamin D3 into 25-hydroxyvitamin D and to activate 25-hydroxyvitamin D into the active steroid hormone form.