Lactose Intolerance and Evolution

"Most Americans are aware of lactose intolerance, and most view it as a minor health problem--an inconvenience, not life threatening, to be sure, but definitely an abnormality. After all, when a person is lactose intolerant, his or her body cannot do something it is supposed to, namely digest dairy foods. A glance around the world, though, reveals that lactose intolerance is the rule, rather than the exception, raising the possibility that it is not a disease but the natural human state." (Gastronomica) This article explores the theory that "lactose tolerance is a genetic mutation that afforded some people a survival advantage and as a consequence was passed down to their offspring."