Magnesium and Vitamin D Metabolism

Ted Hutchinson posted a link in the comments section of my last post, pointing to a page on the Vitamin D Council's website where Dr. John Cannell discusses cofactors required for proper vitamin D metabolism. It's actually the site's home page, highlighting how important he feels this matter is. In this case, 'cofactor' simply means another nutrient that's required for the efficient production and use of vitamin D. They include:

• Magnesium
• Zinc
• Vitamin K2
• Vitamin A
• Boron

And probably others we aren't yet aware of. On another page, Dr. Cannell links to two papers that review the critical interaction between magnesium status and vitamin D metabolism (1, 2). Here's a quote from the abstract of the second paper:

Magnesium... is essential for the normal function of the parathyroid glands, metabolism of vitamin D and adequate sensitivity of target tissues to [parathyroid hormone] and active vitamin D metabolites. Magnesium deficit is usually associated with hypoparathyroidism, low production of active vitamin D metabolites, in particular 1,25(OH)2 vitamin D3 and resistance to PTH and vitamin D. On the contrary, magnesium excess, similar to calcium, inhibits PTH secretion. Bone metabolism is impaired under positive as well as under negative magnesium balance.

Magnesium status is critical for normal vitamin D metabolism, insulin sensitivity, and overall health. Supplemental magnesium blocks atherosclerosis in multiple animal models (3, 4). Most Americans don't get enough magnesium (5).

The bottom line is that no nutrient acts in a vacuum. The effect of every part of one's diet and lifestyle is dependent on every other part. I often talk about single nutrients on this blog, but my core philosophy is that a proper diet focuses on Real Food, not nutrients. Tinkering with nutritional status using supplements is potentially problematic. Despite what some people might tell you, our understanding of nutrition and human health is currently rather crude-- so it's best to respect the accumulated wisdom of cultures that don't get the diseases we're trying to avoid.