Chinese researchers conclude that there is "serious debate" around findings from long-term and multigenerational studies on GM foods
The following review of long-term and multigenerational animal feeding studies with GM crops, by Chinese researchers, is not new – but it is a useful roundup of the safety questions raised in such studies.
The authors concluded: "It appears that there is no adverse effect of GM crops observed for many species of animal in acute or short-term feeding studies, but serious debate still surrounds long-term and multigenerational feeding studies… Therefore, long-term and multigenerational feeding studies are clearly necessary to further investigate [on] this important issue."
This certainly makes clear why defenders of GMOs had to ensure that a "spoiler" review by Snell and colleagues was published soon afterwards. The review authors concluded that there were no ill effects from GM foods in supposedly long-term and multigenerational studies.
How did they reach this conclusion?
1. By analysing studies that were not really long-term at all, in terms of the proportion of the animal's natural lifespan, and were thus not capable of showing health effects that take time to show up, like cancer and organ damage
2. By dismissing toxic effects found in some of the studies
3. By using unscientific double standards to condemn studies finding harm on the grounds that they had methodological weaknesses, while accepting at face value conclusions of safety in studies that suffered from these same weaknesses.
A detailed analysis is in GMO Myths and Truths.
Do genetically modified crops affect animal reproduction? A review of the ongoing debate
W. Zhang and F. Shi
Animal (2011) 5(7): 1048–1059
In the past few years, genetically modified (GM) crops aimed at producing food/feed that became part of the regular agriculture in many areas of the world. However, we are uncertain whether GM food and feed can exert potential adverse effects on humans or animals. Of importance, the reproductive toxicology of GM crops has been studied using a number of methods, and by feeding GM crops to a number species of animals to ensure the safety assessment of GM food and feed. It appears that there are no adverse effects of GM crops on many species of animals in acute and short-term feeding studies, but serious debates of effects of long-term and multigenerational feeding studies remain. The aims of this review are to focus on the latest (last 3 to 4 years) findings and debates on reproduction of male and female animals after feeding daily diets containing the GM crops, and to present the possible mechanism(s) to explain their influences.