Vitamin D is a fat soluble vitamin that helps the body absorb calcium and phosphorus, therefore helps in bone growth and density. It can be naturally produced by the body through sunlight exposure and can be found in a few natural food sources. Not only is Vitamin D important for bone and teeth health, but it has been recently linked to lowering the risks of illnesses such has heart disease, type 1 diabetes and certain cancers.
I found a short summary on Vitamin D on a cooking website I love, EatingWell, which includes a table on the intake recommendations for various age groups. I also love using the American Pediatric Association's website when I have any sort of concern for my kids. Here, they have a whole page list of resources regarding Vitamin D. I loved this resource - especially the simple quiz you can take to see if you are vitamin D deficient: Get Your Vitamin D.com - A resource developed to help correct the country's D deficit. Lastly, here is an article I found on how much sunlight a child needs to synthesize Vitamin D. This article includes links to other interesting articles, including what yogurts contain Vitamin D and additional benefits of Vitamin D.
I would love to hear what you are doing to make sure you and your family are getting enough Vitamin D and any additional related resources.