An article in the journal Critical Care investigated the effect of vitamin D on clinical outcomes in critically ill patients. It was a systemic review and meta-analysis of 16 trials with 2,449 patients.

Vitamin D supplementation was associated with a 23 percent lower overall mortality, 3.13 days shorter intensive care unit stay, and 5.07 days shorter duration of mechanical ventilation. Injectable vitamin D was associated with a greater effect on overall mortality than oral use.

I have been checking vitamin D levels for nearly three decades. Most patients are deficient, particularly in the wintertime when the risk of infectious diseases such as influenza and influenza-like illnesses are common.

Vitamin D is inexpensive and easy to take. Although this study found injectable vitamin D was more beneficial, I think taking an oral version is perfectly fine.

It is important to have optimal levels of vitamin D going into an illness. In the ICU, the gut may not function as well at absorbing vitamin D which would lead to the findings just described.

Optimal levels of vitamin D vary between 50 ng/mL and 90 ng/mL. Most of my patients take approximately 6,000 IU of vitamin D3 per day during the fall and winter months.