No harmful effects of GM maize found in long-term monkey trial

A comprehensive study published in the Journal of Agricultural and Food Chemistry investigates the long-term impacts of genetically modified (GM) maize on the immune status and serum metabolites in cynomolgus macaques. The research, conducted by scientists from the Institute of Medical Biology at the Chinese Academy of Medical Sciences, spanned over seven years and included two generations of macaques.  

The study focused on a specific GM maize variety engineered for insect resistance and herbicide tolerance. The maize contained the cry1Ab/cry2Aj genes for insect protection and the G10evo-EPSPS gene for glyphosate resistance. To assess the potential health effects of this diet, researchers divided 36 cynomolgus macaques into three groups: those fed a GM maize-based diet, those on a non-GM maize diet, and those receiving a standard primate chow.  

Over the study period, both generations of macaques were monitored for changes in their immune profiles, cytokine levels, and serum metabolite compositions. The F0 generation was maintained on their respective diets, while their offspring (F1 generation) continued on the same dietary regimen post-weaning.  

The results revealed that, overall, there were no statistically significant differences in the majority of immune and metabolic parameters between the GM-fed group and the control groups. This suggests that long-term consumption of GM maize does not adversely affect the immune system or metabolic health of cynomolgus macaques.  

Despite minor variations in specific parameters, such as cholesterol levels and a slight reduction in certain cytokines, these differences were not deemed biologically significant. For instance, the levels of immunoglobulins—key indicators of immune function—remained stable across all groups, indicating that GM maize did not trigger abnormal immune responses.

Additionally, the metabolomic analysis identified some differential metabolites, but again, these variations were minimal and not consistently linked to the GM diet. Notably, metabolites like tetrahydrocorticosterone, which can fluctuate due to physiological changes, were found to be elevated in some GM-fed macaques, but researchers attributed this to natural biological variability rather than to the maize itself.  

This study represents a significant contribution to the ongoing discourse surrounding the safety of GM foods. It underscores the importance of using species that are closer in physiology to humans, like cynomolgus macaques, for long-term dietary studies. The findings support the argument for the metabolic equivalence and immunological compatibility of GM maize, which could help refine regulatory standards for genetically engineered food products.  

Source:  

ACS Publications