Fact of the Day
Due to evolution, certain races are genetically predisposed to be either lactose intolerant or not. There has been an age old symbiotic relationship between humans and domesticated cows. The relationship began as people decided to settle down and farm their food rather than chase it. This caused human beings to evolve in accordance with their new environment.
All other types of mammals loose the ability to digest milk in adulthood. Humans are the only ones who attempted to rewrite biology in continuing to drink milk way past breast-feeding, let alone the only species to drink the milk of another animal completely.
In places where cow was the predominant staple of the local diet, the human population adapted in certain ways. From the standpoint of natural selection, Europeans who drank cow milk were more likely live longest and to produce healthy and strong offspring; survival of the fittest. With this in mind, the body mutated, allowing lactose to be digested by adults. Normally the ability goes away after being breast-fed, except in the case of pregnant women who redevelop the ability during pregnancy as a involuntary and precautionary survival measure.
The immunity to cow milk is also big in some parts of Africa. Certain tribes learned how to effectively manage cattle populations too. It is interesting to note that the same mutation occurred in the Africans that occurred in the Europeans as a means of better survival.
The Asian population, more specifically South East Asian, has been adapting away from cattle. Therefore, they are most susceptible to lactose intolerance.
The stats are as follows:
Percentage of Lactose Intolerance (gnxp.com)
Southeast Asians: 98%
Asian Americans: 90%
Alaskan Eskimo: 80%
African Americans Adults: 79%
Mexicans from rural communities: 73.8%
North American Jews: 68.8%
Creek Cypriots: 66%
Mexican American Males: 55%
Indian Adults: 50%
African American Children: 45%
Indian Children: 20%
Caucasians of N. European and Scandinavian decent: 5%
Special thanks for Candace for letting me use a picture of her being Asian.
Lang, Susan. "lactose intolerance and dairy herding." Cornell Chronicle Online. 1 June 2005. 13 Dec. 2008 .
Razib. "Lactose tolerance/intolerance." Gene Expression. 19 Jan. 2004. 13 Dec. 2008 .
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