Changes

Lactose intolerance is a condition where individuals cannot digest [[lactose]], a [[sugar]] found in [[milk]].  When a lactose intolerant individual injests of milk, he or she will get a stomachache.  Other symptons include cramps and bloating.  Such individuals do not produce an [[enzyme]] called [[lactase]] that breaks down lactose after weaning.

Lactose intolerance is a condition where individuals cannot digest [[lactose]], a [[sugar]] found in [[milk]].  When a lactose intolerant individual injests of milk, he or she will get a stomachache.  Other symptons include cramps and bloating.  Such individuals do not produce an [[enzyme]] called [[lactase]] that breaks down lactose after weaning.[http://digestive.niddk.nih.gov/ddiseases/pubs/lactoseintolerance/]

[http://digestive.niddk.nih.gov/ddiseases/pubs/lactoseintolerance/]

The proportion of lactose intolerant individuals varies by region on the planet.  99% of [[China|Chinese]] are lactose intolerant, whereas only 10% of [[United States|Americans]] are. Recent research indicates that lactose intolerance is high where [[cow]]s were not domesticated. [http://evolution.berkeley.edu/evolibrary/news/070401_lactose]At higher latitudes, lactose intolerance decreases.  As average temperature increases, lactose intolerace increases.[http://www.sciencedaily.com/releases/2005/06/050602012109.htm]

[http://evolution.berkeley.edu/evolibrary/news/070401_lactose]

 

[http://www.sciencedaily.com/releases/2005/06/050602012109.htm]

Lactose tolerance is determined by a recessive gene.  Researchers have recently identified a DNA mutation that allows people to tolerate milk.[http://www.foodnavigator.com/news/news-ng.asp?id=42796-scientists-identify-lactose]