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Functions of Vitamin D

The function of vitamin D that is most clearly understood is its role in calcium metabolism.¹ However, there is evidence for emerging roles that have implications for health and prevention of various diseases.

When blood levels of calcium fall, parathyroid hormone (PTH) is released to promote hydroxylation of 25(OH)D to its active form 1,25(OH)₂D. Both PTH and 1,25(OH)₂D mobilize calcium from bone and enhance absorption of calcium from the intestine and kidneys.¹

Vitamin D in its active form also has the capacity to modify cellular activity, cell differentiation and cell proliferation, and therefore may have many roles in physiology and health.¹

Vitamin D receptors have been reported in all tissues including: immune system, brain, heart, pancreas, and intestine, suggesting a role in these tissues.¹ This may explain its association in a wide variety of conditions such as type 1 and type 2 diabetes, multiple sclerosis, schizophrenia, and some cancers.¹

Keywords: vitamin D