Genetic modification of corn plants usually involves the addition of a gene that will either make the plant resistant to a herbicide that will be sprayed on it or cause the plant to produce a pesticide that will kill crop-damaging pests.
Monsanto, an agriculture and biotechnology corporation, sells 90% of the world’s genetically modified (GM) seeds.1 Monsanto lost a court case in Europe and were forced to hand over their data from a 3-month feeding study they had performed on rats using three varieties of their GM corn.
A group of French researchers following up their similar 2007 study re-examined Monsanto’s data using different statistical analyses. The researchers did find some differences between GM corn fed rats and and controls rats using their chosen analyses – most of these changes implied altered kidney or liver function, which could indicate toxicity. 2
The question is – how relevant are these changes? Do they really translate into toxicity in humans? We can’t really know yet. Even the authors of the study stress that the parameters measured are ‘signs of toxicity’ but not ‘proof of toxicity’. Additional longer studies will need to be done to clarify these findings and determine whether GM corn varieties are safe.
The deletion or addition of one gene can change the expression of hundreds or even thousands of other genes, making the genetically modified plant quite different from the original. We don’t know for sure if GM corn is dangerous, but based on the physiological changes that took place in this study, it might be dangerous.
Most of the GM corn that is produced in the U.S. is consumed by farmed animals like cattle and pigs, not by humans. But if GM corn is damaging to the health of these animals, how does this affect the humans that eat them? Also some ingredients in processed foods like high fructose corn syrup, cornstarch, and soy products can potentially be from GM sources (if not labeled organic). We can make a conscious decision not to consume GM foods by avoiding meat and processed foods that contain GM corn or soy ingredients.
1. Wikipedia: Monsanto http://en.wikipedia.org/wiki/Monsanto
2. de Vendômois JS et al. A Comparison of the Effects of Three GM Corn Varieties on Mammalian Health. 2009; 5(7):706-726