There are three essential items that I never leave home without ... my phone, my wallet, and my bottle of sunscreen. My husband and I are both fair-skinned folks, and our daughters are paler than pale. So it's a rare rainy day when we don't slather the stuff all over ourselves and our kids.

But the latest studies show that maybe we don't need to be so vigilant. Researchers estimate that 1 billion people worldwide do not have enough vitamin D, the main source of which comes through exposure to sunlight.

And a new study conducted by researchers at Oxford University found just how important vitamin D is in our body's growth and development. The study mapped vitamin D — also known as the sunshine vitamin — to see how it interacted with human DNA. Their study found that vitamin D has a direct influence on the development of more than 200 genes.  

Because of this, they recommend some exposure to sunshine or taking vitamin D supplements during pregnancy and in the first few years of life to help reduce the risk of a wide ranges of illness, including multiple sclerosis, Crohn's disease and some types of cancer.