Feel free to make any conclusion you like. There are plenty of facts around this subject that are readily available.
Taken from:
http://www.longlifeclub.com/article.php?aid=188
(An interesting sidebar is that since NAFTA opened up Mexico to cheap U.S. corn exports in 1994, the domestic price of corn in Mexico has dropped a staggering 70%. This has been absolutely disastrous for Mexican farmers, many of them have had to leave their farms and migrate to Mexico City where they live in dire poverty alongside 22 million people.)