A review of the neuroprotective role of vitamin D in traumatic brain injury with implications for supplementation post-concussion

A Medline search identified 165 studies of vitamin D and traumatic brain injury, of which only five met inclusion criteria: four rodent models and one clinical sample. Vitamin D alone reduced inflammation and neuronal injury after brain injury, with a stronger effect when combined with progesterone, and one study showed vitamin D deficiency worsened the post-injury inflammatory response. The single clinical study found combination therapy better than progesterone alone or placebo after severe traumatic brain injury, and one study found low-dose vitamin D worked better than high-dose when combined with progesterone. The authors conclude vitamin D supplementation cannot yet be recommended to improve outcomes after brain injury.