Vitamin D--Does the Source Matter?
The following is an excerpt from The Willner Window radio program, which can be heard every Sunday on WOR (710 AM) from 2 to 4 pm, or over the internet at www.wor710.com.
Arnie: Good afternoon everyone, this is .... Welcome to The Willner Window. For those of you who might be first-time listeners, the focus of this show is nutritional supplements–vitamins, herbs, homeopathic remedies–and their proper usage. With me this afternoon is . . We are going to start off the program today with some information on vitamin D.
Don: Vitamin D has been receiving a lot of attention lately. As most of you know, vitamin D is required for our body to properly utilize calcium in the formation of bone. In addition, we now see a lot of research that it may play a role in reducing certain types of cancer, such as breast cancer and colon cancer.
The body can make its own vitamin D, when sunlight interacts with the skin. In addition, you can get it from food, or supplements.
As some of you know, there are two types of vitamin D used in foods and supplements, vitamin D2 and vitamin D3.
Arnie: We explain the differences between the two in our book, The Best Supplements For Your Health. Vitamin D2 is identified as “ergocalciferol” and vitamin D3 is identified as “cholecalciferol.”
D2 is derived from plant sources, and D3 is derived from animal sources. For this reason, vegetarians have sometimes expressed as preference for vitamin D2. The vitamin D3 form is most widely used, however.
Dr. Podell: But there may be other differences. In findings recently presented by researchers from Creighton University in Omaha, shows that there is significantly greater potency in the D3 form over the D2 form.
This is important because research now indicates that more people are actually deficient in vitamin D than was previously thought to be the case. Warnings to pregnant women and children has been issued, for example, advising them to take vitamin D supplements to prevent a resurgence of rickets.
There is concern that the increased use of sun protection creams might be reducing the amount of vitamin D produced in the skin.
Arnie: The study involved giving a large dose, 50,000 IU’s, of one form of vitamin D or the other, randomly, to 20 healthy male volunteers. Over a period of 28 days, blood levels of vitamin D and its product 25-hydroxyvitamin D were measured.
The two calciferols produced similar rises in serum concentration of the native vitamin, indicating equivalent absorption. Both forms of vitamin D produced similar in