What are the health effects of eating genetically modified food?
That’s the question Séralini and colleagues sought to answer by studying rats fed Round-up tolerant genetically modified (GM) corn (with and without 0.1 ppb Roundup in water) for a period of two years.
Publishing their findings on September 19, 2012 in Food and Chemical Toxicology, rats fed GM corn had shorter life spans, severe liver and kidney damage, and developed large mammary tumors compared with control rats.
This study has become a media firestorm both in the European Union and the United States. The French Prime Minister, Jean-Marc Ayrault, has requested that the National Agency for Health Safety review the study. Austria has asked the EU to reconsider their approval process for safety of genetically modified food. And, in the US, this research has provided strong support for California’s Proposition 37, an initiative to place labels on genetically modified food, something that is already required in at least 50 countries.
But all might not be as it seems. This study has come under criticism for several reasons. First, the type of rat used, Sprague Dawley, is susceptible to developing mammary tumors when their diet is not properly controlled. Second, the number of control rats used was low (n=20 males and females; 10 per sex) to draw definitive conclusions. Third, rats fed the largest percentage of GM corn, had less severe symptoms compared with the lowest percentage group.
Despite hundreds of peer-reviewed feeding studies supporting the safety of GM food, Séralini and colleagues have lumped GM food into cigarette smoking or bisphenol A consumption.
Now, the question becomes not is GM food safe to eat, but rather how valid is this study?
Tim Worstall has provided an interesting argument to the topic. Harlan, the provider of rats used in this study, has used genetically modified corn in their rat chow for the last ten years. If GM corn was increasing the formation of tumors and causing liver and kidney necrosis in laboratory animals, scientists and veterinarians would have noticed these health concerns years ago. Tim suggests we use common sense when examining the conclusions drawn from this study.
Regardless, the media coverage following this study will help sway the court of public opinion against GM food. As for myself, I agree with Tim.
Update: October 4, 2012
The European Food Safety Authority has determined that a French study supporting the toxic effects of genetically modified corn was poorly designed and therefore does not support the conclusions made in the paper. The authors have until October 12th to address concerns raised by the agency.