Thankfully, this deficiency is easy to combat by taking daily vitamins. I'm totally addicted to "Sunny Gummies" which are packed with 1000 IU of vit D and taste like delicious sour lemon candy. Check them out, it's an easy way to combat the winter blues. D is also found naturally in some fish, fish liver oils, egg yolks and fortified dairy and grain products.
PS. This is not a sponsored post (I wish!) just a little tip on one of my current favorite things.