Vitamin D is unlike regular "vitamins" because it is actually a steroid hormone that you get through sun exposure, supplementation, or diet. Vitamin D is important because it has been shown to prevent many diseases, certain cancers, influenza, the common cold, bone health and so on. So, how do you know your levels? Next time you go to your doctor ask for a simple blood test. Based on that your doctor may recommend that you supplement. Most doctors recommend 1000 to 2000 IU a day. Food sources include salmon, egg yolks, and fortified milk, cereal and orange juice.
Do you have any nutrition questions?
Ask me! firstname.lastname@example.org