Is GMO Corn Killing Me?

A recent French study suggests that eating genetically modified corn will produce an increase tumors in mammals.  The study, published in the Food and Chemical Toxicology Journal, details the findings of French researchers after feeding Genetically Modified (GMO) corn (maize) and the herbicide Roundup to rats for two years.  Rats were divided in various groups, some were fed GMO corn at different levels, some were fed GMO corn and given doses of Roundup, some were only given Roundup, and few were left in the control group.  Gilles-Eric Séralini, one of the researches from the University of Caen in France, said:  “The results were really alarming”:

In females, all treated groups died 2–3 times more than controls, and more rapidly. This difference was visible in 3 male groups fed GMOs. . . . Females developed large mammary tumors almost always more often than and before controls, the pituitary was the second most disabled organ; the sex hormonal balance was modified by GMO and Roundup treatments. . . .  Males presented 4 times more large palpable tumors than controls which occurred up to 600 days earlier.

In a telephone news conference shortly thereafter, Seralini said most studies about feeding GMO corn were shorter, meaning they probably missed the tumors that developed over the longer two-year period this study undertook.

Critics surfaced immediately. One of the more thorough discussions I've read of the report can be found on Discover Magazine's website: Under Controlled: Why the New GMO Panic is More Sensational than Sense. Discover explains that the study utilized a type of rat that is predisposed to grow tumors (up to 57% of females develop tumors, "spontaneously"). But the larger problem is the size of control group--only 10 rats. Anthony Trewavas, a cell biologist at the University of Edinburgh, described this as “inadequate to make any deduction.”

Discovery Channel News was also critical: GM Corn-Tumor Link Based on Poor Science.  Discovery quoted Martina Newell-McGloughlin, a  a plant bio-technologist at the University of California, Davis, as saying:  

There is very little scientific credibility to this paper.  The flaws in the test are just incredible to me. To be totally honest with you, the type of statistical analysis they used is really a type of fishing expedition. One individual referred to it as "fantasy statistics."

Discovery News pointed out that the level of tumors in the rats remained the same regardless of how much GMO corn they consumed or Roundup they ingested.  If there was a causal connection, toxicity should have increased with consumption amounts.

Discover raised a common sense question:  If GMOs are prone to causing drastic increases in the growth of tumors, why haven't we seen this happen in humans?  

For now, please pass the chips and salsa.