A Closer Look at GE Corn Findings

A long-term animal toxicity study claiming adverse effects of genetically engineered (GE) corn 1 has caused an international maelstrom. The study examined how exposure to the herbicide Roundup® and NK603 Roundup Ready® maize (GE corn engineered to withstand glyphosate, the active ingredient in Roundup) affected Sprague-Dawley rats over a 2-year period, roughly equivalent to 65 years in humans. 2 Images from the paper of enormous tumors in the rats have riveted the public, yet researchers and industry have raised numerous concerns about the design of the study, which was led by Gilles-Eric Séralini, a molecular biology professor at the University of Caen in France. The authors also came under fire for insisting journalists sign an agreement preventing contact with third parties prior to publication, an unheard-of embargo term, 3 which they claimed would prevent leaks of the sensitive paper. 4 Upon publication of the article, the European Commission asked the European Food and Safety Agency (EFSA) to assess whether the findings warranted revisiting earlier safety assessments of NK603. In its assessment EFSA determined the study design and statistical analysis to be of insufficient quality for use in food safety risk assessment. 5 The agency concluded by inviting the authors to provide additional documentation so the study could be assessed more thoroughly, an invitation that had not been accepted when this article went to press. In a separate review, the German Federal Institute for Risk Assessment assessed the glyphosate findings specifically and concluded that the main findings were not supported by the data. 6 The investigators studied a total of 100 male and 100 female rats, with each sex divided into 10 treatment groups of 10 animals each. Three groups of each sex were given feed supplemented with different doses of NK603 that had been grown with Roundup, three were given feed containing untreated NK603, and three were given a standard diet but water containing Roundup. One control group for each sex was fed a standard diet and plain water. The team examined the rats twice weekly, sampled blood and urine throughout the study, and conducted a histologic examination of nine different organs. According to the authors, females in all treatment groups suffered higher mortality rates than controls as a result of tumors forming sooner and more often, with Roundup-only animals developing the most tumors. By the final month, they wrote, 50–80% of treated females had visible tumors, compared with only …