It is interesting to find out that tribes in Africa like Papua New Guinea practice ritual cannibalism.  The Papau New Guinea tribe practices cannibalism because it is cultural tradition. Through this cultural tradition members of the tribe have developed genetic mutations that protect them for the disease called Kuru.  Kuru is a prion disease that affects animals, and humans.  Brain eating seems to be the answer to Kuru but I think that is dependant solely on the demographic and the resources that they are supplied with. The research done on kuru in unique population helps scientists learn more about how the disease is related to genetic mutations of proteins rather than exposure to kuru.

response:http://www.nhs.uk/news/2009/11November/Pages/brain-eating-cannibals-CJD-mad-cow-disease.aspx