Vitamin D Supplementation

Question: I recently bought a Vitamin D supplement when my friend told me that it wasn't worth taking unless it was Vitamin D3. Is that true and what is the difference?


Answer: There are two forms of vitamin D that are important to humans --ergocalciferol (D2) and cholecalciferol (D3). D3 is the type that is synthesized by humans in the skin when exposed to ultraviolet rays from the sun. However, when foods are supplemented with vitamin D, it may be in the form of D2 or D3. When purchasing a vitamin D supplement, it is largely assumed that it is in the form of D2 and or D3, so it is not necessary, in my opinion, to specifically look for a D3 supplement.

Also keep in mind that Vitamin D is found in many food sources such as (fortified) milk, eggs and fish. As little as 10 minutes of sun exposure a day is thought to be enough to prevent deficiencies (leading to rickets and/or osteomalacia).

As for supplementation, I recommend getting a Calcium supplement (women over the age of 50 need 1200 mg Calcium/day and many do not get this consistently from their diet) that contains vitamin D as vitamin D is necessary for calcium absorption. This way, you are likely to get enough Calcium and vitamin D and can do it all in one pill!