You can get sunlight, it's just that Vit. D is believed to raise testosterone and may sway blue.
For most people, your body is able to store many months of Vit. D in your body fat and you don't need it (plus the LE Diet does offer opportunities to get Vit. D via diet, just not the massive amounts present in supplements.) Some people, who don't get much sun otherwise, are dark skinned, and/or don't eat much dairy, may be a little lower in Vit. D to start out with but you cannot know that without a blood test.