1.3—Bt Corn Statistics Don’t Lie
Insect protected GM-corn has been repeatedly scrutinized in laboratory safety studies and is reaffirmed as being at least as safe as conventional corn.
Analysis of Peer-Reviewed Research: Everyone has heard Benjamin Disreali’s famous quote, “There are lies, damn lies, and statistics.” Gilles-ErikSéralini claims that Monsanto’s data show that there are statistically significant differences between the control groups and those fed Mon863. It’s important to recognize that when a large number of comparisons are made, there will always be a small number of comparisons that show seemingly significant differences. In fact, the statisticians must choose how they define what is “different” and obviously, the narrower the range allowed by the definition, the more differences will be seen. Séralini cooked the numbers in an attempt to make it appear that results obtained with GM corn were more different (than Monsanto had found) than those obtained with conventional corn. One test of false differences is to see if groups fed different amounts of the corn being tested develop proportionate differences. This of course is not true since differences that were observed at 11 percent corn in the diet were not observed at 33 percent, but more importantly, experts have consistently concluded that none of the differences have any biological significance—that is to say they would not harm the animals in any way.
- Animal study experts have agreed with Monsanto’s analysis and rejected Séralini’s claims. The safety testing in laboratory experiments of MON 863 corn and particularly the concerns raised by Gilles-Erik Séralini quoted in Genetic Roulette have been re-examined by scientists and regulatory authorities worldwide. These experts reaffirmed in the peer-reviewed scientific literature that MON 863 corn is safe—Smith neglects to tell us that experts have rejected Séralini’s claims (Séralini and others 2007; Doull and others 2007; see also EFSA commentary at www.efsa.europa.eu/EFSA/efsa_locale-1178620753812_1178621165358.htm)
- Genetic Roulette doesn’t tell us about other studies. Smith omits any mention of a of other published laboratory studies that demonstrate that MON 863 corn is safe (Taylor and others 2003 ; Grant and others2003).
- Gilles-Erik Séralini’s report on this corn contains errors in statistical analysis. Biological systems always display variability. For example, the average weight of a group of animals may be 20 gm, but some animals may weigh 10 gms and some may weigh 30. We can use statistics to determine if a specific animal’s weight is within the range normally observed for its group, or if it is really different. Think of it this way, an archer will miss a small target much more often than a large target, so the statistician always has to specify the size of the target. Séralini selected a method that would make it appear that there were more differences—a smaller target, but it is not the method that most experts would use. Genetic Roulette neglects to tell us that Séralini actually confirmed Monsanto’s analysis.
- The claimed differences were not observed under all conditions and were not biologically significant. One way to test if an observed difference is real or coincidental—a false positive—is to feed animals two different amounts of the corn being tested, usually at 11 percent and 33 percent in the diet. In this study, effects seen at 11 percent were not seen at the higher dose. That’s a sure clue that they were false positives but Séralini counted them anyway. Perhaps more important, expert pathologists studied the differences and concluded that none of them were biologically significant and none would have any adverse effect on the animal. Séralini and Smith are therefore fear-mongering about differences that make no difference.
Doull J, Gaylor D, Greim HA, Lovell DP,Lynch B, Munro IC (2008). Report of an Expert Panel on the reanalysis by Séralini et al. (2007) of a 90-day study conducted by Monsanto in support of the safety of a genetically modified corn variety (MON 863).
Food and Chemical Toxicology 45:2073–2085. Critical rebuttal of Séralini and others 2007 . EFSA (June 2007b) EFSA reaffirms its risk assessment of genetically modified maize MON 863 www.efsa.europa.eu/EFSA/efsa_locale-1178620753812_1178621165358.htm accessed Dec 8 2008
Grant R, Fanning K, Kleinschmit D, Stanisiewski E, Hartnell G (2003). Influence of glyphosate-tolerant -event NK603- and corn rootworm protected -event Mon863- corn silage and grain on feed consumption and milk production in Holstein cattle.
Journal of Dairy Science. 86(5): 1707 – 1715. Further investigation on the same strain of maize studied by Séralini and others 2007. Séralini G-E, Cellier D, de Vendomois JS (2007). New analysis of a rat feeding study with a genetically modified maize reveals signs of hepatorenal toxicity.
Archives of Environmental Contamination and Toxicology 52:596-602. Reworking of existing animal feeding trials previously submitted to regulatory authorities, but using a questionable and unusual statistical approach not accepted by other scientists.
Taylor M, Hyun Y, Hartnell, G, Riordan S, Nemeth M, Karunanandaa K, George B, Astwood J (2003). Comparison of broiler performance when fed diets containing grain from YieldGard Rootworm – MON863, YieldGard Plus – MON810 x MON863, Nontransgenic Control, or Commercial Reference Corn Hybrids. Poultry Science. 82: 1948-1956. Further investigation on the same strain of maize studied by Séralini and others 2007.
- Rats were fed Monsanto’s MON 863 Bt corn for 90 days.
- These rats showed significant changes in their blood cells, livers and kidneys which might indicate disease.
- The Monsanto company’s response to critical interpretations of these experiments were unscientific and contradictory.
A genetically modified corn called MON 863 marketed by the Monsanto company has been examined for a wide range of effects on rats and some of these effects are different from its conventional parent corn.