Bowing to scientists' near-universal scorn, the journal "Food and Chemical Toxicology" today fulfilled its threat to retract a controversial paper claiming that a genetically modified (GM) maize causes serious disease in rats, after the authors refused to withdraw it. The link to this story plus the links in the article provide insight into critical thinking. The comments submitted by the many readers are also very interesting.
The study lost credibility because the number of rats involved in the study were very small. Also, the time involved invalidated the results. The rats were fed GMO maize for two years, virtually the entire lifespan of a rat. The rats used in the experiment are a strain that spontaneously develops tumors especially in their older age. These rats are normally used in tumor experiments such as the ones showing how diets high in Omega-6 make tumors grow faster versus rats fed diets with proper EFA ratios. But when experiments go to the very end of the lifespan of rats genetically predisposed to develop tumors, the tests become invalid because of the genetics of the rats and nothing else. If tests supporting the proper EFA balance for retarding cancerous growths had been conducted decades ago the same way as this now famous, discredited GMO rat test, the conclusion that a diet high in Omega-6 fatty acids causes cancers to grow rapidly would have been highly criticized.
There is good science and bad science on both sides of many studies. Just because one group or another does not like the outcome that is no reason to debunk a study. If that was true there would be no advancement in any field of endeavor. It is the credibility of a study that is all important. Also, one study rarely proves anything. For a scientific point to be accepted as fact, studies have to be replicated numerous times. This discredited rat study has not been replicated even once -- even by those highly apposed to GMO feeds.
If something is inherently bad, it must be recognized. To claim something is bad for human health based on no evidence discredits the blaming of bad foods based on evidence.