February 23, 2012 - Recent research led by researchers at the University of Caen (France) indicates that insecticidal Bt toxins such as those produced in genetically engineered plants can be detrimental to human cells.

Bt toxins and tolerance to herbicides are broadly used in genetically engineered plants. Bt proteins only naturally occur in soil bacteria. By introducing the modified toxin gene into the plants, the structure of the toxins is modified and may thereby cause selectivity to be changed. The content of the proteins within the plants is highly variable. Many genetically engineered plants contain several Bt toxins at the same time. For example, SmartStax produces six different Bt toxins and therefore has a higher overall content of the proteins. In addition, it was made tolerant to herbicides. So far, there has been no investigation of the combinatorial effects of these toxins and residues from spraying, or their potential risks for human health, which was considered unlikely. The researchers have now shown that interactivity does occur.

The research showed that toxins produced in GM maize can significantly impact the viability of human cells. Monsanto’s position is that the toxins are supposed to be active only against particular insects and should have no effect on mammals and humans at all. For the first time, experiments have now shown that they can have an effect on human cells. 

Another interesting fact uncovered by the research concerns a herbicide formulation sold under the brand name Roundup. Massive amounts of this herbicide are sprayed on genetically engineered soybean crops and its residues can be found in food and feed. The research showed that even extremely low dosages of Roundup (glyphosate formulations) can damage human cells.  These findings are in accordance with several other investigations highlighting unexpected health risks associated with glyphosate preparations.

Gilles-Eric Séralini from the University of Caen, who supervised the experiments stated; “We were very much surprised by our findings. Until now, it has been thought almost impossible for Bt proteins to be toxic to human cells.. --- these experiments show that the risks of Bt toxins and of Roundup have been underestimated.”

For More information: “Mesnage R., Clair E., Gress S., Then C., Székács A., Séralini G.-E., 2012, Cytotoxicity on human cells of Cry1Ab and Cry1Ac Bt insecticidal toxins alone or with a glyphosate-based herbicide, Journal of Applied Toxicology” - http://onlinelibrary.wiley.com/doi/10.1002/jat.2712/abstract