Fat-soluble Vitamins

So today we're going to finish talking about the fat-soluble vitamins. I'm going to start with vitamin D and I think probably most of you know that vitamin D is called the sunshine vitamin and it's called that because there's absolutely no dietary need for vitamin D if you get adequate sunshine and the real important word there is it because it turns out that in climates which aren't near the equator there's a big question as to whether or not using these you get adequate sunshine and that's important because foods are not naturally abundant in vitamin D and that's why milk is fortified but the fortification may not be enough so again just exposure to sunlight is adequate no need for vitamin D so vitamin D really isn't the vitamin. It's a pro-hormone. When human beings evolved, we evolved in tropical climates and ran around naked. There was plenty of skin exposure to sunlight and so there was no dietary need for vitamin D. as humans migrated away from tropical regions. They created a need for vitamin D in food. Because sunlight was inadequate, particularly during the winter.