Recently, there was a very interesting article published in PNAS entitled "Hominids adapted to metabolize ethanol long before human-directed fermentation". In a nutshell this article details the use and evolution of the ADH4 enzyme in the metabolism of alcohol. Interestingly, this enzyme is also important in the metabolism of Vitamin A. What the authors found was actually very impressive in that they showed this enzyme is present in the other apes as well, however it is not as effective at metabolizing alcohol as it is in humans. Then by going back into the fossil record the showed that this enzyme in humans became more active at metabolizing alcohol about 10 million years ago.
This is fascinating, as it is around that time when our ancestors are to believed to have moved from the trees into the plains. The authors believe that the mutation that occurred to create a more efficient ADH4 enzyme was beneficial to these ancestors as they were able to metabolize the alcohol that would naturally occur in fallen fruit. By being able to do this, our ancestral humans would have not being drunk and as such had an evolutionary advantage.This change in environment lead us eventually to walking upright and becoming who we are today awesome apes that can read, type and understand.
Well unless you are a creationist.Apparently, if you are a creationist this article means that we are evolved to be drunks.
Some times my palm just explodes through the back of my head.