I think this issue has come up now because Jordan Rubin in his new book, The
Maker's Diet, uses biblical food standards as the basis of what's ok to eat
and what's now. Having grown up in a kosher home, I was always told that
asking for the scientific explanation of why you can or cannot eat something
was not relevant. Spiritual rather than health reasons guided one's choice
of food. I no longer follow a kosher diet but some members of my family do.
I guess its personal relevance today would be an individual thing.

Jean