Dr. Arash Hossein-Nezhad, currently a scholar at Boston University has teamed up with senior author Professor Michael Holick to write a spectacular in-depth review about vitamin D for the highly respected journal, Mayo Clinic Proceedings.

The publication covers so many things we currently kow about vitamin D, it makes a compelling case for a spectacular role of vitamin D in human health. Here were some highlights and questions answered:

Q: Can vitamin D be washed off the skin?

The authors say no, it can’t.

Approximately 65% of the vitamin D precursor, 7-dehydro-cholesterol, is found in the epidermis. More than 95% of the pre-vitamin D3 that is produced is in the living cells of the epidermis (underneath the hard cornified outer layer) and thus cannot be removed from the skin by washing.

This explains a forgotten 1937 paper in which the authors proved that irradiated surface skin oils of young men cured rickets in animals and was removed by washing. It is probably the 5% of vitamin D made on the surface of the skin that was removed by washing.

Q: Is there a difference between vitamin D derived from sun exposure and from food/supplements?

Ingested vitamin D appears to differ from sun-derived vitamin D only in the fact that ingested vitamin D is first transported away from the guy by chylomicrons before it binds to D-binding protein in the lymphatic system. Otherwise, vitamin D3 is vitamin D3, no matter if it’s coming from your skin or oral intake.

Click here to read the entire article in Smart Tan Magazine online.