A quick and cheap genetic test will soon be able to identify people with lactose intolerance. The test will be a boon for doctors, since many people suffer from the condition without realising it, and existing tests are time-consuming and unreliable.
For perhaps the majority of people in the world, including most southern European, Asian and African populations, lactose intolerance is the norm. It sets in at weaning or shortly after, when the body stops producing lactase - the enzyme it needs to digest the sugar lactose, which is a major ingredient of human and animal milk.
Without lactase, lactose passes through the stomach undigested and reaches bacteria in the large intestine. There some bugs feast on it, belching out by-products that can leave people feeling gassy and nauseous, or worse.
Now Leena Peltonen's team at the University of California, Los Angeles, has discovered the genetic basis for lactose intolerance. The discovery supports the theory that retaining the ability to digest milk evolved only in some peoples in the past ten thousand years, as an adaptation to dairy farming.
read more here: http://www.newscientist.com/article.ns?id=dn1787




