Vitamin D is the only vitamin we can make by standing in the sun. We can also eat it in fish, beef liver and mushrooms Most milk, cereal and orange juice is fortified with vitamin D, so many people supplement their vitamin D without even thinking about it.
http://www.livescience.com/42481-vitamin-d-supplement-facts.html
http://www.livescience.com/42481-vitamin-d-supplement-facts.html
