While it is well known that vitamin D plays a crucial role in overall bone health, studies suggest that vitamin D might also play an important role in protecting against respiratory infections like colds and the flu. And it does this through its effects on lung development and structure, respiratory muscle contractile strength, inflammation, and immune response to respiratory pathogens. This vitamin is essential to our well-being, especially during times like this, and being out in the sun is the best way to get it.