Ever wonder why the California Milk Processor Board keeps producing their got milk? ads, even after nearly 16 years?

An interesting factoid: Less than 40 percent of the world's population retains the ability to digest lactose after childhood. While up to 90 percent of northern European populations can digest milk (particularly in Ireland, the Netherlands and Sweden), the numbers are nonexistent -- close to 0 -- among Native Americans, only 5 percent among Asians and 25 percent among Africans and Caribbean groups.

The ability to drink and digest milk may not be normal, according to this interesting USA Today feature. In fact, a patient's inability to drink the white stuff may not truly be a disease (lactose intolerance). Many scientists believe those who consume milk into adulthood possess a genetic mutation -- lactase persistence -- that allows them to do it.

A recent UK study has shown through computer modeling how this mutation first appeared in dairy farmers living between the center Balkans and central Europe some 7,500 years ago.

USA Today September 1, 2009

PLOS Computational Biology August 2009 Free Full Text Study

Baltimore Sun August 21, 2009

EurekAlert August 27, 2009

Journal of Allergy and Clinical Immunology August 10, 2009 Free Full Text Study