Sunshine, Supplements, and Fortified Foods
I was worried about not getting enough Vit D, too. I did some research, and 10-15 minutes 3 days a week of direct sunshine will give you enough Vit D - you just need your arms and legs exposed, or your back to get enough. Also, most cereals and juices are enriched with Vit D and others that are hard to get.
It is nearly impossible to get it all just from your food, unless it has been enriched. If you arent someplace where it is warm enough to go out in shorts and t shirt, you will likely need a supplement.
Hope that Helps,